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A check list of bacteria associated with infection in humans 

A check list of bacteria associated with infection in humans

A check list of bacteria associated with infection in humans

J. Paul


May 30, 2013: This chapter has been re-evaluated and remains up-to-date. No changes have been necessary.


Chapter reviewed, minor changes made.

Updated on 31 May 2012. The previous version of this content can be found here.
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date: 21 August 2017


In addition to the relatively small number of well-known pathogenic bacteria that are able to infect otherwise healthy people, e.g. Staphylococcus aureus, Mycobacterium tuberculosis, and Streptococcus pyogenes, there is a steadily growing list of less well known organisms, many of which are able to cause disease only under special circumstances.

All bacteria associated with infections in humans are listed in the table that forms the bulk of this chapter, which has been designed to serve as a single port of call for clinicians who seek concise information on the less well known clinically significant bacteria. Every name in the table has been checked to see that it has ‘standing in nomenclature’: widely used names that do not have standing in nomenclature (at the time of writing) are included, but written in inverted commas (e.g. ‘Spirillum minus’—one of the causes of rat bite fever). For an up-to-date check on nomenclature, the reader is referred to Reported antibiotic susceptibilities and treatments are listed as a rough guide only: for some organisms the only available published information consists of in vitro test results for small numbers of strains, or apparent clinical response to therapy for a single case. There is no substitute for the determination of the susceptibilities of organisms as they are cultured on a case-by-case basis in tandem with the monitoring of therapeutic response.

Geographical restriction and particular exposures—some pathogenic bacteria, e.g. Burkholderia pseudomallei (the cause of melioidosis), are associated with special geographical areas; others are associated with particular forms of exposure, e.g. some Actinobacillus species with animal bites, and Rickettsia species with tick bites.

Bacterial commensals and usually harmless environmental organisms as causes of disease—given the right kind of help, bacteria that live usually as harmless human commensals can cause disease, e.g. skin commensals such as Staphylococcus epidermidis can cause line sepsis and infect prosthetic devices; gut commensals such as Bacteroides species can grow in abscesses; and oral commensals such as Streptococcus salivarius can cause endocarditis. Immunosuppressed patients, ventilated patients, and patients undergoing continuous ambulatory peritoneal dialysis are vulnerable to infection by a wide range of otherwise harmless environmental organisms.

Improved understanding of disease processes and discovery of ‘new’ pathogens—a refined understanding of, e.g. periodontal disease, has resulted in the characterization of new organisms such as Pseudoramibacter alactolyticus, Johnsonella ignava, Centipeda periodontii, and Capnocytophaga gingivalis: some of these have subsequently been identified in systemic infections such as bacteraemia.

Impact of new laboratory techniques—these have revealed the presence of new species and new disease associations, e.g. Tropheryma whipplei was associated with Whipple’s disease by molecular methods before the organism was cultured; molecular methods have detected oddities like Bradyrhyzobium elkanii in aortic aneurysm tissue, although its role as potential pathogen is doubtful.

Changes in nomenclature—amidst the discovery of new bacteria, taxonomic rearrangements and changes in nomenclature pile on additional layers of confusion for the clinician. For example, it has been recognized that organisms formerly known as Burkholderia cepacia are actually a complex of several genomospecies, which have been given individual names. It is also confusing when a well-known genus is split to reflect the recognition that its composite species are a number of groups that are only distantly related, e.g. many organisms that were once known as Bacteroides species. New organisms will continue to be described and name changes will continue to occur.

For an up-to-date check on nomenclature, the reader is referred to

Table A check list of bacteria associated with infection in humans


Associated infections

Reported susceptibilities and treatments



Species and subspecies

(synonyms, CDC alphanumeric groups)


[Abiotrophia adiacens—see Granulicatella adiacens]


A. defectiva

Endophthalmitis, brain abscess, osteomyelitis, peritonitis, endocarditis

Vancomycin, ceftriaxone (plus gentamicin or rifampicin)

Previously known as nutritionally deficient or variant streptococci

[Abiotrophia elegans—see Granulicatella elegans]

[‘Abiotrophia para-adiacens’—see Granulicatella notes]

Achromobacter (Alcaligenes)

  • A. denitrificans

  • A. insolitus

  • A. piechaudii

  • A. ruhlandii

  • A. spanius

  • A. xylosoxidans

Septicaemia, CAPD peritonitis, pneumonia, ear infection, pulmonary infection in cystic fibrosis, keratitis, vascular line sepsis

Ureidopenicillins, ceftazidime, carbapenems

[Achromobacter CDC group Vd and Achromobacter groups A, C, and D—see Ochrobactrum]

[Achromobacter groups B and E—see Pannonibacter]


A. fermentans

Abscesses, postsurgical infections


Acidovorax (Pseudomonas)

  • A. avenae

  • A. delafieldii

  • A. facilis

  • A. temperans

Wound infection, UTI, bacteraemia, meningitis, septic arthritis


  • A. baumannii

  • A. calcoaceticus

  • A. haemolyticus

  • A. johnsonii

  • A. junii

  • A. lwoffi

  • A. parvus

  • A. radioresistens

  • A. schindleri

  • A. ursingii

Septicaemia, UTI, wound infections, abscesses, endocarditis, meningitis, osteomyelitis

Aminoglycosides, ureidopenicillins, ceftazidime, carbapenems, tigecycline

May be multidrug-resistant. Nosocomial outbreaks reported. Infections associated with debilitated patients

[Actinobacillus actinomycetemcomitans—see Aggregatibacter actinomycetemcomitans]


  • A. equuli

  • A. lignieresii

  • A. suis

Wound infection, abscesses, endocarditis, meningitis

Ampicillin (plus gentamicin for endocarditis)

Associated with animal contact and bites

A. hominis

Septicaemia, empyema


A. ureae (Pasteurella ureae)

Meningitis, pneumonia, endocarditis, hepatitis, peritonitis

Ampicillin (plus gentamicin for endocarditis), chloramphenicol

Respiratory tract commensal in humans


  • A. massiliense

  • A. schaalii

  • A. urinale

Pyelonephritis, UTI, septicaemia, superficial skin infection

Penicillin, cefuroxime, nitrofurantoin, tetracycline, clindamycin


  • A. Latina

  • A. madurae

  • A. pelletieri

  • A. vinacea

Actinomycetoma, Madura foot

Co-trimoxazole, dapsone


  • A. cardiffensis

  • A. dentalis

  • A. europaeus

  • A. funkei

  • A. georgiae

  • A. gerencseriae

  • A. graevenitzii

  • A. hongkongensis

  • A. israelii

  • A. meyeri

  • A. naeslundii

  • A. neuii neuii

  • A. neuii anitratus

  • A. odontolyticus

  • A. oricola

  • A. radicidentis

  • A. radingae

  • A. turicensis

  • A. urogenitalis

  • A. viscosus




A. incenata

Pulmonary infection, bacteraemia


  • A. sanguinicola

  • A. urinae

  • A. urinaehominis

  • A. viridans

Endocarditis, UTI, wounds, meningitis, abscesses, CAPD peritonitis, lymphadenitis, spondodactylitis

Penicillin, vancomycin (plus gentamicin for endocarditis)


  • A. allosaccharophila

  • A. bestiarumA. Caviae

  • A. enteropelogenes

  • A. hydrophila

  • A. jandaei

  • A. media

  • A. salmonicida

  • A. schubertii

  • A. trota (A. tructi)

  • A. veronii

Wound infection, abscesses, septicaemia, meningitis, leech-bite infection, alligator-bite infection, acute diarrhoea

Aminoglycosides, chloramphenicol, ceftazidime, co-trimoxazole

Infections associated with aquatic exposure. A. veroniiincludes biovars Veronii and Sobria. The taxonomic status of some species is unclear. The status of A. allosaccharophila is controversial. A. trota may be a synonym of A. enteropelogenes


A. felis

Cat-scratch disease

Imipenem, aminoglycosides

Cat-scratch disease is associated also with Bartonella spp.

A. broomeae

Bone marrow infection, septic arthritis

Imipenem, aminoglycosides

Role as pathogen uncertain

A. clevelandensis

Bone infection

Imipenem, aminoglycosides

Role as pathogen uncertain

  • A. birgiae

  • A. massiliensis


Imipenem, aminoglycosides

Roles as pathogens uncertain


A. actinomycetemcomitans (Actinobacillus actinomycetemcomitans, Haemophilus actinomycetemcomitans)

Periodontitis, endocarditis, abscesses, pericarditis, meningitis

Penicillin (plus gentamicin for endocarditis), ceftriaxone, coamoxiclav

Human oral commensal. Some strains reported to be penicillin-resistant

A. aphrophilus (Haemophilus aphrophilus, H. paraphrophilus)

A. segnis (Haemophilus segnis)

Sinusitis, otitis media, pneumonia, abscesses, endocarditis

Ceftriaxone, cefotaxime, chloramphenicol, ampicillin, aminoglycosides


A. radiobacter (A. tumefaciens)

Endocarditis, CAPD peritonitis, UTI, line sepsis

Co-trimoxazole, gentamicin, amikacin, piperacillin-tazobactam

The nomenclature of this taxon is unsettled. The names A. tumefaciens and A. radiobacter both have standing in nomenclature. Transfer of Agrobacterium to Rhizobium has been proposed

[Alcaligenes denitrificans—see Achromobacter denitrificans]


  • A. faecalis

  • A. latus

Pneumonia, otitis, UTI, osteomyelitis, bacteraemia

Amoxicillin–clavulanate, cephalosporins, fluoroquinolones

[Alcaligenes xylosoxidans—see Achromobacter xylosoxidans xylosoxidans]

[Alcaligenes piechaudii—see Achromobacter piechaudii]

[Alcaligenes ruhlandii—see Achromobacter ruhlandii]


A. fetalis

From fetal necropsy specimen

Clinical significance uncertain


  • A. finegoldii (Bacteroides finegoldii)

  • A. onderdonkii

  • A. putredinis (Bacteroides putredinis)

  • A. shahii

Appendicitis, peritonitis, abdominal abscess

Metronidazole, ertapenem

β‎-Lactamase producers. Abdominal infections, found in association with other anaerobes


A. otitis (Alliococcus otitis)

Otitis media


[Amycolata autotrophica—see Pseudonocardia autotrophica]


A. orientalis (Nocardia orientalis)

Role as pathogen uncertain

A. palatopharyngis

Palatopharyngeal infection

Clinical significance poorly defined


  • A. succiniproducens

  • A. thomasii

Diarrhoea, bacteraemia

Cefuroxime, tetracycline, chloramphenicol

Infection may be related to exposure to cat or dog faeces

Anaerococcus (Peptostreptococcus)

  • A. hydrogenalis

  • A. lactolyticus

  • A. octavius

  • A. prevotii

  • A. tetradius

  • A. vaginalis

Mixed anaerobic infections, abscesses

β‎-Lactams, metronidazole


A. geminatus

From postoperative collection

Role as pathogen uncertain

Anaerorhabdus (Bacteroides)

A. furcosus

Lung abscess, appendix and abdominal abscesses

[‘Anguillina coli’—see Serpulina pilosicoli]


A. phagocytophilum



Previously known as human granulocytic ehrlichiosis

[Arachnia propionica—see Propionibacterium propionicus]


A. haemolyticum (Corynebacterium haemolyticum)

Tonsillitis, cellulitis, lymphadenopathy, brain abscess, septicaemia, osteomyelitis

Penicillin, erythromycin

A. bernardiae (Actinomyces bernardiae)

UTI, septicaemia, septic arthritis


Previously known as CDC coryneform group 2

A. pyogenes (Actinomyces pyogenes)

Septic arthritis


Arcobacter (Campylobacter)

  • A. butzleri

  • A. cryaerophilus

Abdominal cramps, diarrhoea



  • A. albus

  • A. creatinolyticus

  • A. cumminsii

  • A. luteolus

  • A. oxydans

  • A. scleromae

  • A. woluwensis

UTI, bacteraemia, skin infection

Vancomycin, penicillins

Arthrobacter sp. has been implicated in Whipple’s syndrome, a disease usually associated with Tropheryma whipplei


  • A. minutum (Lactobacillus minutus)

  • A. parvulum (Streptococcus parvulus)

  • A. rimae (Lactobacillus rimae)

UTI, dental abscesses, pelvic abscesses, wound infection

Isolates from periodontal sites suggest possible role in periodontal disease

A. vaginae

Bacterial vaginosis

[Aureobacterium—see Microbacterium]


A. brasilense (Roseomonas fauriae)

CAPD peritonitis, line sepsis

Imipenem, aminoglycosides, ceftriaxone, ciprofloxacin



B. anthracis


Penicillin, erythromycin

Ciprofloxacin for postexposure prophylaxis

[Bacillus brevis—see Brevibacillus agri]

  • B. circulans

  • B. coagulans

  • B. megaterium

  • B. mycoides

  • B. sphaericus

  • B. thuringiensis

Pneumonia, septicaemia, corneal infections, meningitis, food poisoning, eye infection, lung infection

Vancomycin, clindamycin, aminoglycosides, imipenem, penicillin

Other than the well-known B. anthracis and B. cereus, Bacillus spp. are rare causes of focal and systemic sepsis. Some isolates are resistant to vancomycin. Isolates may represent specimen or laboratory contamination. B. thuringiensis is a biological insecticide which has caused corneal infection

  • B. cereus

  • B. licheniformis

  • B. pumilus

  • B. subtilis

Food poisoning, wound infection, cutaneous lesions, bacteraemia, endocarditis, eye infection

Clindamycin, vancomycin, gentamicin

Diarrhoea is self-limiting. B. cereus is resistant to β‎-lactams


  • B. caccae

  • B. capillosus

  • B. coagulans

  • B. eggerthii

  • B. finegoldii

  • B. fragilis

  • B. massiliensis

  • B. nordii

  • B. ovatus

  • B. pyogenes

  • B. salyersae

  • B. splanchinicus

  • B. stercoris

  • B. tectus

  • B. thetaiotaomicron

  • B. uniformis

  • B. ureolyticus

  • B. vulgatus

Abscesses, bacteraemia, bite infections, wound infections, chronic otitis media, pelvic inflammatory disease, neonatal sepsis

Ureidopenicillins, carbapenems, metronidazole

Resistance to metronidazole and β‎-lactams has been reported. Many species previously classified as Bacteroides have been transferred to other genera: see Alistipes, Anaerorhabdus, Campylobacter, Dialister Mitsuokella, Parabacteroides, Prevotella, Porphyromonas, and Tannerella


B. alpica

Pneumonia, bacteraemia, meningitis

Ceftriaxone, ofloxacin, amoxicillin, netilmicin

Infection associated with exposure to hot spring water


B. bacilliformis

Oroya fever, verruga peruana

Chloramphenicol, streptomycin

B. elizabethae (Rochalimaea elizabethae)


Gentamicin, imipenem, co-trimoxazole

  • B. clarridgeiae

  • B. henselae (Rochalimaea henselae)

Cat-scratch disease, bacillary angiomatosis

Aminoglycosides, doxycycline

Cat-scratch disease is associated also with Afipia felis

B. quintana (Rochalimaea quintana)

Trench fever, bacillary angiomatosis

Aminoglycosides, doxycycline

B. schoenbuchensis

Deer ked dermatitis

Evidence to associate this organism with deer ked dermatitis is circumstantial

B. vinsonii arupensis



Zoonosis from rodents


B. zoohelcum (Weeksella zoohelcum)

Wound infection, septicaemia, meningitis

Cefotaxime, penicillins, ciprofloxacin, tetracycline

Associated with dog and cat bites


  • B. adolescentis

  • B. angulatum

  • B. bifidum

  • B. dentium

  • B. longum (B. infantis)

  • B. pseudocatenulatum

Bacteraemia, abscesses, peritonitis, otitis, paronychia

Clindamycin, penicillins, cefoxitin

Reported risk factors include surgery, malignancy, steroid therapy, intravenous drug use, and acupuncture. Some strains used as probiotics

[Bifidobacterium inopinatum—see Scardovia inopinata]


B. wadsworthia

Appendicitis, abscesses, bacteraemia, biliary tract sepsis, mastoiditis

Metronidazole, amoxicillin/clavulanate, ureidopenicillins, cephalosporins


B. bronchiseptica

Respiratory tract infection

Tetracycline, fluoroquinolones

Zoonosis from dogs and other animals

  • B. hinzii

  • B. holmesii

  • B. trematum

Bacteraemia, otitis, wound infection

B. hinzii is a pathogen of poultry

  • B. parapertussis

  • B. pertussis

Whooping cough, respiratory tract infection


B. parapertussis causes less severe disease


  • B. afzelii

  • B. andersoni

  • B. bissettii

  • B. burgdorferi

  • B. garinii

  • B. japonica

  • B. lusitaniae

  • B. sinica

  • B. spielmanii

  • B. tanukii

  • B. turdi

  • B. valaisiana

Lyme disease

Amoxicillin, doxycycline, ceftriaxone

  • B. caucasica

  • B. crocidurae

  • B. duttonii

  • B. graingeri

  • B. hermsii

  • B. hispanica

  • B. latyschewii

  • B. mazzottii

  • B. parkeri

  • B. persica

  • B. recurrentis

  • B. turicatae

  • B. venezuelensis

Relapsing fever

Tetracycline, erythromycin, chloramphenicol, penicillin

B. recurrentis is louse-borne; other agents are tick-borne


B. massiliensis

Linked with ventilator-associated pneumonia

Doxycycline, telithromycin

Amoeba-resisting bacterium from hospital water supplies


  • B. aalborgi

  • B. pilosicoli (Serpulina pilosicoli, ‘Anguillina coli’)

Intestinal spirochaetosis

Of uncertain significance


B. elkanii

Detected in tissue from aortic aneurysm

Potential role as pathogen uncertain

[Branhamella catarrhalis—see Moraxella catarrhalis]


B. centrosporus



Previously confused with B. laterosporus and reported as such in clinical literature

B. parabrevis

Bacteraemia, abscess



  • B. casei

  • B. epidermidis

  • B. luteolum (B. lutescens)

  • B. mcbrellneri

  • B. otitidis

  • B. paucivorans

Bacteraemia, endocarditis, meningitis, chest infection, pericarditis, vascular catheter sepsis


Brevundimonas (Pseudomonas)

  • B. diminuta

  • B. vesicularis

Septicaemia, endocarditis

Cefazolin, ceftriaxone, piperacillin (plus gentamicin for endocarditis)


  • B. abortus

  • B. canis

  • B. melitensis

  • B. suis


Doxycycline (plus streptomycin or rifampicin)

The four species names used for clinical purposes represent biovars of a single species, B. melitensis


B. extructa

Necrotizing ulcerative periodontitis in HIV patients

Burkholderia (Pseudomonas)

  • B. ambifaria

  • B. anthina

  • B. cenocepacia

  • B. cepacia (Pseudomonas cepacia)

  • B. dolosa

  • B. multivorans

  • B. pyrrocinia

  • B. stabilis

  • B. vietnamiensis

Lung infection in cystic fibrosis, bacteraemia, endocarditis, septic arthritis, UTI

Ureidopenicillins, ceftazidime, aztreonam, carbapenems, fluoroquinolones, co-trimoxazole

B. cepacia sensu stricto and other taxa listed are genomospecies of the B. cepacia species complex (B. cepacia sensu lato). Hard to differentiate by routine methods. Differences in disease progression in cystic fibrosis may relate to different genomospecies

B. gladioli (Pseudomonas gladioli)

Lung infection in cystic fibrosis

Ureidopenicillins, ceftazidime, aztreonam, carbapenems, fluoroquinolones, co-trimoxazole

B. fungorum

Septic arthritis, bacteraemia, meningitis

Amoxicillin, cefuroxime, ceftazidime, ciprofloxacin, meropenem, co-trimoxazole

B. mallei (Pseudomonas mallei)


Sulfadiazine, co-amoxiclav, tetracycline, co-trimoxazole

B. pseudomallei (Pseudomonas pseudomallei)


Ceftazidime, co-trimoxazole, chloramphenicol, imipenem


  • B. agrestis

  • B. noackiae

Appendicitis, wound infection

Aminoglycosides, doxycycline

Cephalosporin resistance reported


B. fibrisolvens


Penicillin, chloramphenicol

From rumina of farm animals


[Calymmatobacterium granulomatis—see Klebsiella granulomatis]

[Campylobacter butzleri—see Arcobacter butzleri]

[Campylobacter cinaedi—see Helicobacter cinaedi]

[Campylobacter fennelliae—see Helicobacter fennelliae]

[Campylobacter pyloridis—see Helicobacter pylori]


  • C. coli

  • C. jejuni jejuni

  • C. jejuni doylei

  • C. mucosalis

Gastroenteritis, bacteraemia

Erythromycin, fluoroquinolones

Infections are usually self-limiting

  • C. concisus

  • C. curvus (Wolinella curva)

  • C. gracilis (Bacteroides gracilis)

  • C. rectus (Wolinella recta)

  • C. showae

  • C. sputorum

Periodontitis, appendicitis, peritonitis, head and neck infections, abscesses

Ureidopenicillins, amoxicillin/clavulanate, carbapenems, fluoroquinolones, metronidazole

C. fetus fetus

Fever, diarrhoea, meningoencephalitis, endocarditis, abscesses

Erythromycin, ampicillin, chloramphenicol, gentamicin

C. fetus venerealis

Bacterial vaginosis

Role as human pathogen poorly defined. Reported from faeces of homosexual men

  • C. hyointestinalis

  • C. lari (C. laridis)

  • C. upsalensis

Diarrhoea, bacteraemia, abscess

Erythromycin, ampicillin, gentamicin

Zoonoses from mammals and birds


  • C. canimorsus (CDC DF-1)

  • C. cynodegmi (CDC DF-2)

  • C. gingivalis

  • C. granulose

  • C. haemolytica

  • C. ochracea

  • C. sputigena

  • Wound infection, septicaemia, abscesses, meningitis, endocarditis

  • Periodontitis, septicaemia

  • Penicillin

  • Penicillins, ciprofloxacin, tetracycline, chloramphenicol

  • From dog bites

  • From oral flora. Infections associated with malignancy and neutropenia


  • C. hominis

  • C. valvarum

Endocarditis, meningitis

Penicillin (plus gentamicin for endocarditis)


C. morbi

Periodontitis, endodontic infection

Role as pathogen unclear


Bite infections



  • C. davisae

  • C. lapagei

  • C. neterii


Chloramphenicol, cefamandole, gentamicin

Two other species (sp. 3 and sp. 5) have been isolated from clinical specimens


  • C. denverensis

  • C. hominis (CDC coryneform group A-3)

Bacteraemia, meningitis, pilonidal abscess, wound infection, homograft valve infection

Clarithromycin, clindamycin, imipenem, minocycline, rifampicin, vancomycin

[Cellulomonas cellulans—see Cellulosomicrobium]

[Cellulomonas turbata—see Oerskovia turbata]


  • C. cellulans (Cellulomonas cellulans, Oerskovi xanthineolytica)

  • C. funkei

Meningitis, pyonephrosis, CAPD peritonitis, endophthalmitis

Vancomycin and gentamicin or rifampicin


C. periodontii


Role as pathogen unclear. Shown to inhibit lymphocytes


C. trachomatis

Trachoma, genital infection, neonatal infection, lymphogranuloma venereum

Erythromycin, tetracycline, azithromycin

Includes 18 serovars clustered into two biovars: trachoma and lymphogranuloma venereum


C. abortus (Chlamydia psittaci)


Associated with contact with infected ruminants

C. pneumoniae (Chlamydia pneumoniae)

Chest infection


Infections in humans associated with biovars TWAR

C. psittaci (Chlamydia psittaci)



Zoonosis from birds


C. violaceum

Septicaemia, osteomyelitis, abscesses, eye infection

Erythromycin, tetracycline, chloramphenicol, gentamicin

Associated with exposure to soil and water

Chryseobacterium (Flavobacterium)

  • C. gleum

  • C. indologenes

Bacteraemia, abdominal sepsis, vascular catheter sepsis

Piperacillin-tazobactam, minocycline, fluorquinolones, rifampicin

Susceptibilities vary. Often multiresistant

[Chryseobacterium meningosepticum—see Elizabethkingia meningoseptica]

[Chryseomonas luteola—see Pseudomonas luteola]


  • C. amalonaticus

  • C. braakii

  • C. diversus

  • C. farmeri

  • C. freundii

  • C. gilenii

  • C. koseri

  • C. murliniae

  • C. rodentium

  • C. sedlakii

  • C. werkmanii

  • C. youngae

UTI, meningitis, bacteraemia, haemolytic–uraemic syndrome

Aminoglycosides, β‎-lactams

Variable susceptibility. May be multiresistant. Nosocomial outbreaks of infection reported. Citrobacter spp. are part of the normal faecal flora


  • C. argentinense

  • C. baratii

  • C. beijerinckii

  • C. bifermentans

  • C. bolteae

  • C. butyricum

  • C. cadaveris

  • C. carnis

  • C. celatum

  • C. clostridioforme

  • C. cochlearium

  • C. cocleatum

  • C. fallax

  • C. ghonii

  • C. glycolicum

  • C. haemolyticum

  • C. histolyticum

  • C. indolis

  • C. innocuum

  • C. irregulare

  • C. leptum

  • C. limosum

  • C. malenominatum

  • C. novyi

  • C. oroticum

  • C. paraputrificum

  • C. piliforme

  • C. putrefasciens

  • C. ramosum

  • C. sardiniense (C. absonum)

  • C. septicum

  • C. sordellii

  • C. sphenoides

  • C. sporogenes

  • C. subterminale

  • C. symbiosum

  • C. tertium

Wound infection, bacteraemia, abscesses

Penicillin, clindamycin, metronidazole

Many Clostridiumspp. have been isolated form clinical specimens. For most, their clinical significance is poorly defined. C. baratiiandC. butyricum are rare causes of botulism. C. fallax, C. histolyticum, C. novyi, C. septicum, and C. sordellii are gas-gangrene agents. Treatment of gas gangrene includes debridement and penicillin, clindamycin, or metronidazole

C. botulinum


Antitoxin and respiratory support as treatment

C. difficile

Diarrhoea, pseudomembranous colitis

Metronidazole, vancomycin

Infection associated with antibiotic exposure

C. perfringens

Food poisoning, necrotizing enterocolitis, gas gangrene

Debridement and penicillin, clindamycin, or metronidazole for treatment of gas gangrene

C. tetani


Metronidazole, penicillin

Antitoxin and supportive treatment


C. aerofaciens

From faecal flora. Clinical significance is undefined

[Comamonas acidovorans—see Delftia acidovorans]

Comamonas (Pseudomonas)

  • C. terrigena

  • C. testosteroni

Bacteraemia, UTI, conjunctivitis, endocarditis, wound infection, abdominal abscess, peritonitis, meningitis

Ureidopenicillins, ceftazidime, ciprofloxacin, aminoglycosides, imipenem

Infections in neutropenic patients. Infections associated with animal bite and exposure to tropical fish


  • C. accolens

  • C. afermentans

  • C. amycolatum

  • C. appendicis

  • C. argentoratense

  • C. atypicum

  • C. aurimucosum (C. nigricans)

  • C. auris

  • C. bovis

  • C. confusum

  • C. coyleae

  • C. durum

  • C. falsenii

  • C. freneyi

Septicaemia, peritonitis, UTI, eye infection, wound infection, endocarditis, osteomyelitis, septic arthritis, meningitis, abscesses

Glycopeptides, β‎-lactam, erythromycin, rifampicin

More than 40 Corynebacterium spp. have been isolated from clinical specimens. For many of them, clinical significance and empirical therapy are poorly defined. Many isolates are susceptible to β‎-lactams. Multiresistant, vancomycin-susceptible isolates of CDC coryneform group G-2, C. jeikeium and C. urealyticumhave been reported. Nosocomial outbreaks have been reported. Corynebacteriumspp. may be specimen or laboratory contaminants. CDC coryneform groups 1, E, F-1, and G-2 await designation of scientific names

  • C. glucuronolyticum

  • C. imitans

  • C. jeikeium

  • C. kroppenstedtii

  • C. kutscheri

  • C. lipophilum

  • C. macginleyi

  • C. matruchotii

  • C. mucifaciens

  • C. pilosum

  • C. propinquum

  • C. renale

  • C. resistens

  • C. riegelii

  • C. sanguinis

  • C. singulare

  • C. striatum

  • C. sundsvallense

  • C. thomssenii

  • C. tuberculostearicum

  • C. tuscaniense

  • C. urealyticum

  • C. xerosis

C. diphtheriae

Diphtheria, cutaneous infection

Penicillin, erythromycin

Toxigenic infection requires treatment with antitoxin

C. minutissimum

Erythrasma, bacteraemia, endocarditis

Role as an agent of erythrasma is poorly defined

C. mycetoides

Tropical ulcer, septicaemia

C. pseudodiphtheriticum

UTI, endocarditis, lymphadenopathy, necrotizing tracheitis


C. pseudotuberculosis

Lymphadenitis, pulmonary infection

Penicillin, erythromycin

Associated with sheep contact. May require drainage or excision

C. ulcerans

Diphtheria-like disease, pharyngitis

Penicillin, erythromycin

Toxigenic infection requires treatment with antitoxin

C. vitaeruminis

Associated with aortic aneurysm

Role as pathogen uncertain

[Corynebacterium group A-3—see Cellulomonas]

[Corynebacterium groups A-4 and A-5—see Microbacterium]

[Corynebacterium group 2—see Arcanobacterium bernardiae]


C. burnetii

Q fever

Tetracycline, ciprofloxacin, co-trimoxazole, rifampicin


C. curtum


Cupriavidus (Ralstonia) (Wautersia)

  • C. gilardii

  • C. pauculus

  • C. respiraculi

  • C. taiwanensis

Meningitis, pulmonary infection in cystic fibrosis, line sepsis

Cephalosporins, imipenem, co-trimoxazole, quinolones, amikacin



D. acidovorans (Comamonas acidovorans)

Bacteraemia, endocarditis

Ureidopenicillins, fluoroquinolones


D. hominis

Brain abscess, bacteraemia, wound infection

Cephalosporins, glycopeptides


D. sp.

Associated with aortic aneurysm

Role as pathogen uncertain. Found on skin and mucous membranes


D. congolensis

Cutaneous infection


Zoonosis from cattle, sheep, goats, and horses


D. orale



D. piger (D. pigra)

Pilonidal cyst abscess, peritonitis

From faecal flora


  • D. desulfuricans

  • D. vulgaris

Bacteraemia, liver abscess

Penicillin, clindamycin

D. fairfieldensis

Cultured from urine of patient with UTI and meningoencephalitis

Proposed name does not have standing in nomenclature


  • D. invisus

  • D. micraerophilus

  • D. pneumosintes

  • D. propionicifaciens

Periodontitis, endodontic infection, bacteraemia


D. nodosus (Bacteroides nodosus)

Pilonidal cyst, rectal fistula, wound infection

Cause of ovine footrot. Isolates reported from humans may not be D. nodosus


D. maris

Prosthetic hip infection, bacteraemia

Vancomycin, teicoplanin, rifampicin, amoxicillin, gentamicin, clindamycin, co-trimoxazole

Papillomatosis has been associated with ‘Dietzia strain X’


D. paucivorans




D. pigrum

Spinal cord infection, eye infection

Significance as a pathogen poorly defined.


  • D. capnocytophagoides (CDC group DF-3)

  • D. gadei

  • D. mossii

Diarrhoea, bacteraemia, abscess

Tetracycline, clindamycin, imipenem



  • E. hoshinae

  • E. ictaluri

  • E. tarda

Wound infection, abscesses, gastroenteritis

β‎-Lactams, aminoglycosides, fluoroquinolones

Aquatic exposure, penetrating fish injury


  • E. hongkongensis

  • E. lenta (Eubacterium lentum)

  • E. sinensis

Rectal abscess, bacteraemia

Penicillin, metronidazole

Variable susceptibility to cefotaxime


  • E. chaffeensis

  • E. ewingii


Tetracycline, doxycycline

Antibodies to E. muris detected in healthy humans in Japan

[Ehrlichia sennetsu—see Neorickettsia sennetsu]


E. corrodens

Septicaemia, endocarditis, abscesses, septic arthritis

Penicillin (plus gentamicin for endocarditis)


E. meningoseptica (Chryseobacterium meningosepticum, Flavobacterium meningosepticum)

Meningitis, bacteraemia, endocarditis, necrotizing fasciitis, pneumonia

Quinolones, co-trimoxazole, minocycline, rifampicin

Treatment with vancomycin is controversial


E. brevis (Flavobacterium breve)

Endophthalmitis, bacteraemia, UTI

Broad-spectrum cephalosporins



  • E. aerogenes

  • E. amnigenus

  • E. asburiae

  • E. cancerogenus

  • E. cloacae

  • E. gergoviae

  • E. hormaechei

  • E. kobei

  • E. ludwigii

  • E. sakazakii

Bacteraemia, respiratory tract infections, UTI

Carbapenems, fluoroquinolones, aminoglycosides, ureidopenicillins

May be multiresistant. Common cause of nosocomial infection


  • E. avium

  • E. casseliflavus (E. flavescens)

  • E. cecorum

  • E. dispar

  • E. durans

  • E. faecalis

  • E. faecium

  • E. gallinarum

  • E. gilvus

  • E. hirae

  • E. malodoratus

  • E. mundtii

  • E. pallens

  • E. pseudoavium

  • E. raffinosus

  • E. solitarius

Bacteraemia, abscesses, endocarditis, meningitis, UTI, peritonitis, osteomyelitis, wound infection

Penicillins, glycopeptides

May be resistant to penicillins and glycopeptides. Nosocomial outbreaks reported


E. persicinus


Cephalosporins, fluoroquinolones, aminoglycosides

The causative agent of necrosis of bean pods


E. rhusiopathiae

Erysipeloid, septicaemia, endocarditis


Animal contact

[Escherichia adecarboxylata—see Leclercia adecarboxylata]


E. albertii


Previously known as Hafnia alvei-like strains

E. coli

UTI, bacteraemia, wound infection, meningitis, enteric infection, haemolytic fluoroquinolones, uraemic syndrome

β‎-Lactams, aminoglycosides, co-trimoxazole

Susceptibilities variable

E. fergusonii

Bacteraemia, wounds, UTI

Chloramphenicol, gentamicin


E. hermanii


Chloramphenicol, cephalosporins, gentamicin

E. vulneris


Ampicillin, cephalosporins, gentamicin


  • E. brachy

  • E. combesii

  • E. contortum

  • E. cylindroids

  • E. infirmum

  • E. limosum

  • E. minutum

  • E. moniliforme

  • E. multiforme

  • E. nitrogenes

  • E. nodatum

  • E. plautii

  • E. rectale

  • E. saburreum

  • E. saphenum

  • E. sulci

  • E. tenue

  • E. timidum

  • E. tortuosum

  • E. ventriosum

  • E. yurii yurii

  • E. yurii mararetiae

  • E. yurii schtitka

Wounds, abscesses, septicaemia, periodontitis

Penicillins, clindamycin, metronidazole


E. americana

Septicaemia, wounds, UTI

Ureidopenicillins, aminoglycosides


  • E. acetylicum

  • E. aurantiacum

Wound infection, bacteraemia



  • F. hominis

  • F. ignava

  • F. languida

  • F. sourekii

UTI, bacteraemia, abscess


  • F. alocis

  • F. vilosus

Gingivitis, periodontitis


F. magna (Peptostreptococcus) magnus

[Flavimonas oryzihabitans—see Pseudomonas oryzihabitans]


F. mizutaii (Sphingobacterium mizutae)

[Flavobacterium gleum—see Chryseobacterium gleum]

[Flavobacterium indologenes—see Chryseobacterium indologenes]

[Flavobacterium meningosepticum—see Elizabethkingia meningoseptica]


‘F. rappini’

Bacteraemia, diarrhoea

Not in approved lists of bacterial names. There is a growing consensus that ‘Flexispira’ actually represents several Helicobacter spp.

[Fluoribacter bozemanae—see Legionella bozemanae]

[Fluoribacter dumoffii—see Legionella dumoffii]

[Fluoribacter gormanii—see Legionella gormanii]


F. philomiragia (Yersinia philomiragia)

Septicaemia, invasive systemic infection

Fluoroquinolones, aminoglycosides, chloramphenicol, cefoxitin

F. tularensis


Streptomycin, tetracycline


  • F. gonidiaformans

  • F. mortiferum

  • F. naviforme

  • F. necrogenes

  • F. necrophorum necrophorum

  • F. necrophorum fundiliforme

  • F. nucleatum nucleatum

  • F. nucleatum fusiforme

  • F. nucleatum polymorphum

  • F. nucleatum vincentii

  • F. periodonticum

  • F. russii

  • F. ulcerans

  • F. varium

Abscesses, bacteraemia, periodontitis, endocarditis, necrobacillosis

Metronidazole, penicillins, carbapenems, cephalosporins



G. vaginalis

Intrauterine and neonatal sepsis

β‎-Lactams, clindamycin

Associated with bacterial vaginosis


  • G. bergeri

  • G. haemolysins

  • G. morbillorum (Streptococcus morbillorum)

  • G. sanguinis

Bacteraemia, endocarditis

Penicillin or vancomycin (plus gentamicin for endocarditis)


G. sanguinis

Bacteraemia, UTI, meningitis


Gordonia (Gordona) (Rhodococcus)

  • G. aichensis

  • G. araii

  • G. bronchialis

  • G. effuse

  • G. otitidis

  • G. polyisoprenivorans

  • G. rubropertinctus

  • G. sputi

  • G. terrae

Pulmonary infection, cholecystitis, breast abscess, sternal wound sepsis, brain abscess, bacteraemia, otitis

Co-trimoxazole, ceftriaxone, imipenem, fluoroquinolones


G. adiacens (Abiotrophia adiacens) G. elegans (Abiotrophia elegans)

Endocarditis, septic arthritis, endodontic infection

Penicillin or cefazolin or vancomycin plus gentamicin (plus rifampicin)

Previously known as nutritionally deficient or variant streptococci; the proposed name ‘Abiotrophia para-adiacens’ for strains allied to what is now known as Granulicatella adiacens does not have standing in nomenclature


G. hollisae (Vibrio hollisae)


β‎-Lactams, quinolones

Infection associated with ingestion of shellfish


[Haemophilius aphrophilus—see Aggregatibacter aphrophilus]

[Haemophilius paraphrophilus—see Aggregatibacter aphrophilus]

[Haemophilius segnis—see Aggregatibacter segnis]


H. aegyptius

Brazilian purpuric fever

Ampicillin, cephalosporins, chloramphenicol

Treated by some authors as a biotype of H. influenzae

  • H. parainfluenzae

  • H. pittmaniae

Sinusitis, otitis media, pneumonia, abscesses, endocarditis

Cefotaxime, chloramphenicol, ampicillin, aminoglycosides

The genus Aggregatibacter has been proposed to accommodate H. aphrophilus (including H. paraphrophilus as a heterotypic synonym of H. aphrophilus), H. signis, and Actinobacillus actinomycetemcomitans

H. ducreyi


Macrolides, ceftriaxone, fluoroquinolones

H. influenzae

Bacteraemia, meningitis, epiglottitis

Cephalosporins, penicillins, fluoroquinolones

Many strains produce penicillinases


H. alvei


Doubtful enteropathogen. Susceptibility variable. Includes two genomospecies. ‘Hafnia alvei-like’ strains from Bangladesh have been described as Escherichia albertii


  • H. kunzii

  • ‘H. pyogenica’

  • H. sueciensis

Sebaceous cyst infection, breast abscess, wound infection

Penicillins, vancomycin

From skin flora. The name H. pyogenica does not have standing in nomenclature


H. bilis (‘Flexispira rapinni’ corrig. taxon 9)

Cholecystitis, bacteraemia

Zoonosis from rodents

H. canis


Zoonosis from dogs

H. cinaedi (Campylobacter cinaedi) H. fennelliae (Campylobacter fennelliae)

Proctitis in homosexual men, septicaemia

Ampicillin, gentamicin

Zoonoses from hamsters

  • H. bizzozeronii

  • H. felis

  • H. salomonis

  • ‘Candidatus H. bovis

  • ‘Candidatus H. heilmannii’

  • (‘Gastrospirillum hominis’)

  • ‘Candidatus H. suis

  • (‘H. heilmannii-like organisms’)


Zoonoses from domestic and farm animals. Some organisms known as ‘Flexipsira rapini’ may belong to this group of Helicobacter spp.

  • H. canadensis

  • H. pullorum


Zoonoses from birds (or possibly rodents)

H. pylori (Campylobacter pyloridis)


Omeprazole plus clarithromycin and metronidazole

Numerous similar treatment combinations have been recommended

H. westmeadii

Bacteraemia in AIDS

Name does not have standing in nomenclature

H. winghamensis


Name does not have standing in nomenclature. Possibly a zoonosis from rodents


H. sp.

Associated with aortic aneurism

Detected by 16S gene analysis. Of doubtful clinical significance


H. filiformis

From faecal flora. Clinical significance is unclear





Penicillins, cephalosporins, quinolones

Associated with myiasis


I. ruoffiae

Wound infection, ear abscess

Role as pathogen poorly defined


I. limosusI. sp.

Pulmonary infection in cystic fibrosis, endocarditis

Imipenem, quinolones, gentamicin



J. melonis


Vancomycin, β‎-lactams, fluoroquinolones

An undescribed Janibacter sp. was isolated from a leukaemia patient


J. ignava




K. gyiorum

Wound infection


  • K. denitrificans

  • K. kingae

  • K. oralis

  • K. potus

Septic arthritis, endocarditis, bite infection

Penicillins (plus gentamicin for endocarditis)

[Kingella indologenes—see Suttonella indologenes]


K. granulomatis (Calymmatobacterium granulomatis)


Tetracycline, co-trimoxazole

[Klebsiella ornitholytica, K. planticola, K. terrigena—see Raoultella]

  • K. oxytoca

  • K.pneumoniae ssp. pneumoniae

  • K. pneumoniae ssp. ozaenae

  • K. variicola

UTI, bacteraemia, wound infection, respiratory tract infection

β‎-Lactams, aminoglycosides, fluoroquinolones

Susceptibilities vary. Nosocomial outbreaks reported

K. pneumoniae ssp. rhinoscleromatis


Ciprofloxacin, rifampicin, co-trimoxazole


  • K. ascorbate

  • K. cryocrescens

  • K. georgiana

  • K. intermedia (Enterobacter intermedius)

Bacteraemia, UTI, mediastinitis, line sepsis

Aminoglycosides, ceftazidime, imipenem, ciprofloxacin

Kocuria (Micrococcus)

  • K. kristinae

  • K. rosea

  • K. varians

Cholecystitis, line-related sepsis

Penicillin, clindamycin, vancomycin

[Koserella trabulsii—see Yokenella regensburgei]


‘K. bessonii’

Bacteraemia, endocarditis


Not in approved lists of bacterial names

  • K. gibsonii

  • K. zopfii

Isolated from faeces of patients with diarrhoea

Kytococcus (Micrococcus)

  • K schroeteri

  • K. sedentarius

Endocarditis, cerebral cyst infection

Imipenem, vancomycin, rifampicin



  • L. acidophilus

  • L. brevis

  • L. casei

  • L. catenaformis

  • L. coleohominis

  • L. crispatus

  • L. fermentum

  • L. gasseri

  • L. iners

  • L. jensenii

  • L. leichmannii

  • L. oris

  • L. paracasei

  • L. paraplantarum

  • L. plantarum

  • L. rhamnosus

  • L. salivarius

  • L. vaginalis

Abscesses, bacteraemia, endometritis, endocarditis, lung infection, UTI

Cephalosporins, vancomycin, penicillins, aminoglycosides, clindamycin

Reported risk factors for infection include surgery, malignancy, diabetes, and immunodeficiency. May be vancomycin-resistant

Lactococcus (Streptococcus)

  • L. garviae

  • L. lactis

Bacteraemia, endocarditis, UTI

Penicillin (plus gentamicin for endocarditis)


L. mirabilis

Role as potential pathogen unclear. From oral flora of HIV patients and sputum of cystic fibrosis patient


L. adecarboxylata (Escherichia adecarboxylata)

Bacteraemia, wound infection

Variable susceptibility


  • L. anisa

  • L. birminghamensis

  • L. bozemanae (L. bozemanii)

  • L. cincinnatiensis

  • L. dumoffii

  • L. feeleii

  • L. gormanii

  • L. hackeliae

  • L. israelensis

  • L. jordanis

  • L. lansingensis

  • L. longbeachae

  • L. lytica

  • L. maceachernii

  • L. micdadei

  • L. oakridgemsis

  • L. pneumophila

  • L. quinlivanii

  • L. rubrilucens

  • L. sainthelensi

  • L. tucsonensis

  • L. wadsworthia

  • L. worsleiensis

Legionnaires’ disease, Pontiac fever

Macrolides, fluoroquinolones, rifampicin

Infections caused by species other thanL. pneumophila and L. micdadei are seldom reported


L. aquatica (Corynebacterium aquaticum)

UTI, endocarditis, meningitis, CAPD peritonitis

Ampicillin, chloramphenicol, gentamicin

Previously confused with Aureobacterium (which has been united with Microbacterium)


  • L. grimontii

  • L. richardii

UTI, bacteraemia, surgical site infection, peritonitis

Imipenem, chloramphenicol, tetracycline, gentamicin


  • L. biflexa

  • L. borgpetersenii

  • L. broomii

  • L. inadai

  • L. interrogans

  • L. kirschneri

  • L. noguchii

  • L. santarosai

  • L. weilii


Penicillin, tetracycline

L. interrogans is composed of severalnamed serogroups, including: australis, bataviae, canicola, copenhageni, cynopteri, hurstbridge, hardjo, grippotyphosa, icterohaemorrhagiae, panama, pomona, pyrogenes, sejroe, tarassovi


  • L. buccalis

  • L. goodfellowii

  • L. shahii

  • L. trevisanii

Bacteraemia, endocarditis

β‎-Lactams, metronidazole

Associated with dental plaque and gingivitis. ‘L. amnionii’ from amniotic fluid does not have standing in nomenclature and may belong in the genus Sneathia


  • L. citreum

  • L. lactis

  • L. mesenteroides ssp. cremoris

  • L. mesenteroides ssp. dextranicum

  • L. mesenteroides ssp. mesenteroide

  • L. pseudomesenteroides

Meningitis, bacteraemia, pulmonary infection

Penicillin and gentamicin or clindamycin



  • L. ivanovii

  • L. grayi

  • L. monocytogenes

  • L. seeligeri

Septicaemia, meningitis, intrauterine infection, enteric infection

Ampicillin and gentamicin

[Listonella damsela—see Photobacterium damselae]


  • L. peritonei

  • L. sanguinis

Peritonitis, bacteraemia



M. timonae

Bacteraemia, wound infection


  • M. elsdenii

  • M. micronuciformis

Endocarditis, abscess



M. amorphae



  • M. extorquens

  • M. mesophilicum (Pseudomonas mesophilica)

Bacteraemia, CAPD peritonitis, UTI, septic arthritis

Ureidopenicillins, imipenem, aminoglycosides, chloramphenicol, fluoroquinolones

Detected in aortic aneurysm

Microbacterium (Aureobacterium)

  • M. arborescens

  • M. imperiale (CDC coryneform groups A-4 and A-5)

  • M. liquefaciens (Aureobacterium liquefaciens)

  • (‘Corynebacterium aquaticum’)

  • M. oxydans

  • M. paraoxydans

  • M. resistens

  • M. trichothecenolyticum

Endophthalmitis, UTI, endocarditis, soft tissue infection, hypersensitivity pneumonitis, meningitis, CAPD peritonitis, bacteraemia

Glycopeptides, β‎-lactams, chloramphenicol, gentamicin

M. resistens is vancomycin-resistant. Microbacterium isolates have been misidentified as ‘Corynebacterium aquaticum’ a taxon now known as Leifsonia aquatica


  • M. luteus

  • M. lytae

Bacteraemia, endocarditis, septic arthritis

Vancomycin, penicillin, rifampicin

From skin flora. Common specimen contaminants


M. multocida (Bacteroides multiacidus)

Role as human pathogen poorly defined


Associated infections

Reported susceptibilities and treatments



Species and subspecies

(synonyms, CDC alphanumeric groups)


  • M. curtisii curtisii

  • M. curtisii holmesii

  • M. mulieris

Endometritis, chorioamnionitis

Ampicillin, cephalosporins, clindamycin

Associated with bacterial vaginosis


M. wisconsensis


Of uncertain significance


  • M. diversum

  • M. neglectum

Endodontic infection


  • M. atlantae

  • M. catarrhalis (Branhamella catarrhalis)

  • M. lacunata

  • M. nonliquefaciens

  • M. osloensis

Conjunctivitis, wound infection, endocarditis, abscesses, osteomyelitis, respiratory infections, endocarditis, bacteraemia

Penicillin, cefuroxime

Penicillin resistance has been reported. Some authors retain Branhamella catarrhalis

[Moraxella phenylpyruvica—see Psychrobacter phenylpyruvicus]

[Moraxella urethralis—see Oligella urethralis]


  • M. morganii morganii

  • M. morganii sibonii

Bacteraemia, UTI, wound infection

β‎-Lactams, aminoglycosides

Susceptibilities vary


M. indoligenes


  • M. abscessus

  • M. africanum

  • M. alvei

  • M. asiaticum

  • M. arupense

  • M. aubagnense

  • M. aurum

  • M. avium

  • M. barrassiae

  • M. boenickei

  • M. bohemicum

  • M. bolletii

  • M. bovis

  • M. branderi

  • M. brisbanense

  • M. brumae

  • M. canariasense

  • M. celatum

  • M. chelonae

  • M. chimaera

  • M. chubuense

  • M. colombiense

  • M. conceptionense

  • M. confluentis

  • M. conspicuum

  • M. cookii

  • M. cosmeticum

  • M. doricum

  • M. elephantis

  • M. flavescens

  • M. florentinum

  • M. fortuitum

  • M. gadium

  • M. gastri

  • M. genavense

  • M. goodii

  • M. gordonae

  • M. haemophilum

  • M. hassiacum

  • M. heckeshornense

  • M. heidelbergense

  • M. hodleri

  • M. holsaticum

  • M. houstonense

  • M. immunogenum

  • M. interjectum

  • M. intracellulare

  • ‘M. jacuzzii’

  • M. kansasii

  • M. kubicae

  • M. kumamotonense

  • M. lacus

  • M. lentiflavum

  • M. leprae

  • M. mageritense

  • M. malmoense

  • M. marinum

  • M. massiliense

  • M. microgenicum

  • M. microti

  • M. monacense

  • M. mucogenicum

  • M. neoaurum

  • M. nebraskense

  • M. neworleansense

  • M. nonchromogenicum

  • M. novocastrense

  • M. palustre

  • M. parascrofulaceum

  • M. parmense

  • M. peregrinum

  • M. p hlei

  • M. phocaicum

  • M. porcinum

Isoniazid, rifampicin, ethambutol, pyrazinamide, streptomycin, azithromycin, clarithromycin, ciprofloxacin, dapsone, clofazimine, imipenem, co-trimoxazole, amikacin

Many Mycobacterium spp. have been associated with infection. M. tuberculosis, M. africanum, and M. bovis are the agents of tuberculosis. M. scrofulaceum causes cervical adenitis. The agent of Buruli ulcer is M. ulcerans. M. marinum causes fish-tank granuloma. M. lepraecauses leprosy. M. malmoense, M. szulgai, M. shimoidei, M. kansasii, and M. xenopi cause pulmonary infection. M. intracellulareand M. avium cause systemic infection mainly in immunocompromised patients. The rapid growers, M. chelonae,M. abscessus, and M. fortuitum cause local postinoculation injury and systemic infection

  • M. saskatchewanense

  • M. scrofulaceum

  • M. seoulense

  • M. septicum

  • M. shimoidei

  • M. simiae

  • M. smegmatis

  • M. szulgai

  • M. terrae

  • M. thermoresistibile

  • M. triplex

  • M. triviale

  • M. tuberculosis

  • M. tusciae

  • M. ulcerans

  • M. vaccae

  • M. wolinskyi

  • M. xenopi


  • M. amphoriforme

  • M. buccale

  • M. faucium

  • M. fermentans

  • M. genitalium

  • M. hominis

  • M. lipophilum

  • M. orale

  • M. penetrans

  • M. pirum

  • M. pneumoniae

  • M. primatum

  • M. salivarium

  • M. spermatophilum

Respiratory infection, postpartum fever, pyelonephritis, pelvic inflammatory disease, myocarditis, pericarditis, meningitis

Tetracycline, macrolides, fluoroquinolones

May be resistant to macrolides. M. pneumoniaeinfection may be complicated by haemolytic anaemia, intravascular coagulation, Stevens–Johnson syndrome, or erythema multiforme

M. phocicerebrale (M. phocacerebrale)

Seal finger


Other Mycoplasma spp. from seals are M. phocae and M. phocirhinis

Myroides (Flavobacterium)

  • M. odoratimimus

  • M. odoratus

UTI, wound infection


May be multiresistant



  • N. animaloris

  • (CDC gro up EF-4a)

  • N. canis

  • N. weaveri

  • (CDC group M-5, ‘Neisseria parelongata’)

  • N. zoodegmatis

  • (CDC group EF-4b)

Wound infections, abscesses, endocarditis, meningitis, bacteraemia


Zoonoses from animal bites

  • N. bacilliformis

  • N. cinerea

  • N. elongata elongata

  • N. elongata glycolytica

  • N. elongata nitroreductens

  • N. flavescens

  • N. lactamica

  • N. mucosa

  • N. polysaccharea

  • N. sicca

  • N. subflava

Meningitis, bacteraemia, endocarditis, osteomyelitis

Penicillin, cephalosporins

Bacteraemia in AIDS reported for several species. Penicillin resistance rarely reported in commensal Neisseriaspp. N. subflava includes biovars flava, perflava, and subflava

N. gonorrhoeae

Gonorrhoea, septicaemia, ophthalmia neonatorum


Susceptibility varies geographically. The name ‘Neisseria gonorrhoeae ssp. kochii’ was proposed for isolates from conjunctivitis cases in rural Egypt

N. meningitidis

Septicaemia, meningitis, conjunctivitis, genital infection, epiglottitis

Penicillin, cefotaxime

Rifampicin, ciprofloxacin, or ceftriaxone to clear carriage


N. sennetsu (Ehalichia sennetsu)

Sennetsu fever


Associated with eating raw fish in Asia


  • N abscessus

  • N. africana

  • N. anaemiae

  • N. aobensis

  • N. araoensis

  • N. arthritides

  • N. asiatica

  • N. asteroides

  • N. beijingensis

  • N. brasiliensis

  • N. brevicatena

  • N. carnea

  • N. concave

  • N. cyriacigeorgica

  • N. elegans

  • N. exalbida

  • N. farcinica

  • N. higoensis

  • N. inohanensis

  • N. kruczakiae

  • N. mexicana

  • N. niigatensis

  • N. ninae

  • N. nova

  • N. otitidiscaviarum

Nocardiosis (including bacteraemia, pulmonary and soft tissue infections)

Sulphonamides, co-trimoxazole, amikacin, imipenem

  • N. paucivorans

  • N. pneumoniae

  • N. pseudobrasiliensis

  • N. puris

  • N. sienata

  • N. takedensis

  • N. thailandensis

  • N. testaceus

  • N. transvalensis

  • N. vermiculata

  • N. veterana

  • N. yamanashiensis


  • N. dassonvillei

  • N. synnemataformans

Mycetoma, cutaneous infection, pulmonary infection, conjunctivitis

Fluoroquinolones, piperacillin


Ochrobactrum (Achromobacter CDC group Vd; Achromobacter groups A, C, and D)

  • O. anthropi

  • O. intermedium

Bacteraemia, endophthalmitis, liver abscess

Imipenem, fluoroquinolones, aminoglycosides

Nosocomial infections in debilitated patients


O. turbata (Cellulomonas turbata)

Bacteraemia, endocarditis

Amikacin, co-trimoxazole, chloramphenicol

Vancomycin resistance reported


O. ureolytica (CDC IVe) O. urethralis (Moraxella urethralis)

UTI, septicaemia

Aminoglycosides, cephalosporins

Associated with urinary catheters


O. uli (Lactobacillus uli)


O. tsutsugamushi (Rickettsia tsutsugamushi)

Scrub typhus

Tetracycline, chloramphenicol



  • P. alvei

  • P. macerans

  • P. polymyxa

  • P. popilliae

Septicaemia, meningitis, pneumonia



P. phragmitetus (Achromobacter groups B and E)


  • P. agglomerans (Enterobacter agglomerans)

  • P. ananatis

  • P. dispersa

Bacteraemia, endocarditis, wound infection, cellulitis, alligator-bite infection, endophthalmitis

Carbapenems, fluoroquinolones, ureidopenicillins, aminoglycosides

Susceptibilities vary. May be multiresistant


  • P. distasonis

  • P. goldsteinii (Bacteroides goldsteinii)

  • P. merdae




P. acanthamoebae

Humidifier fever


P. yeei


Ampicillin, cephalosporins, ciprofloxacin


P. micra (Peptostreptococcus micros)


  • P. aerogenes

  • P. bettyae

  • P. canis

  • P. dagmatis

  • P. gallinarum

  • P. haemolytica

  • P. multocida multocida

  • P. multocida gallicida

  • P. multocida septica

  • P. pneumotropica

  • P. stomatis

Wound infection, septicaemia, abscesses, pneumonia, endocarditis, meningitis

Penicillin, tetracycline, ciprofloxacin

Pasteurella infections in humans relate to species usually associated with animals. There may be no history of an animal bite or contact

[Pasteurella ureae—see Actinobacillus ureae]


  • P. acidilactici

  • P. damnosus

  • P. dextrinicus

  • P. parvulus

  • P. pentosaceus

Bacteraemia, abscesses, pulmonary infection

Imipenem, gentamicin, chloramphenicol

Debilitated hospital patients. Resistant to vancomycin


P. niger

Abdominal sepsis

Penicillin, clindamycin

Peptoniphilus (Peptostreptococcus)

  • P. asaccharolyticus

  • P harei

  • P. indolyticus

  • P. ivorii

  • P. lacrimalis

Mixed anaerobic infections, abscesses

β‎-Lactams, metronidazole, chloramphenicol


  • P. anaerobius

  • P. stomatis

  • ‘P. trisimilis’

Mixed anaerobic infections, abscesses, endocarditis

β‎-Lactams, metronidazole, chloramphenicol

See also Peptoniphilus, Anaerococcus, Finegoldia


P. damselae (Listonella damsela and Vibrio damsela)

Necrotizing wound infection, bacteraemia

Penicillins, tetracycline, chloramphenicol

Infection associated with penetrating fish injury. May require debridement

Photorhabdus (Xenorhabdus)

P. luminescens

Bacteraemia, wound infection

Cefoxitin, oxacillin, gentamicin


P. shigelloides

Gastroenteritis, septicaemia, meningitis, endophthalmitis

Ciprofloxacin, trimethoprim, cephalosporins

Infections associated with contaminated food and water

Porphyromonas (Bacteroides)

  • P. asaccharolytica

  • P. cangingivalis

  • P. canoris

  • P. cansulci

  • P. catoniae

  • P. circumdentaria

  • P. crevioricanis

  • P. endodontalis

Mixed anaerobic infections at various sites, periodontitis, human and animal bites

Metronidazole, ureidopenicillins, amoxicillin/clavulanate, carbapenems, cephalosporins, chloramphenicol

Members of the oral flora of humans and animals

  • P. gingivalis

  • P. gingivicanis

  • P. levii

  • P. macacae

  • P. somerae

  • P. uenonis

Prevotella (Bacteroides)

  • P. bergensis

  • P. bivia

  • P. buccae

  • P. buccalis

  • P. corporis

  • P. dentalis

  • P. denticola

  • P. disiens

  • P. enoeca

  • P. heparinolytica

  • P. intermedia

  • P. loeschii

  • P. melaninogenica

  • P. multiformis

  • P. multisaccharivorax

  • P. nigrescens

  • P. oralis

  • P. oris

  • P. oulorum

  • P. tannerae

  • P. timonensis

  • P. veroralis

  • P. zoogleoformans

Abscesses, bacteraemia, wound infection, bite infections, genital tract infections, periodontitis, endodontic infection

Metronidazole, amoxicillin/clavulanate, ureidopenicillins, carbapenems, cephalosporins, clindamycin, chloramphenicol

A genus that includes the well-known former Bacteroides melaninogenicusand allied species of anaerobes


  • P. acnes

  • P. avidum

  • P. granulosum

  • P. propionicum (Arachnia propionicus)

Abscesses, endocarditis, bacteraemia, septic arthritis, endophthalmitis

Glycopeptides, penicillin, macrolides

Associated with acne vulgaris


P. lymphophilum (Propionibacterium lymphophilum)


Isolated from lymph nodes in Hodgkin’s disease


  • P. mirabilis

  • P. penneri

  • P. vulgaris

UTI, bacteraemia, wound infection, abscesses

β‎-Lactams, aminoglycosides, fluoroquinolones

Susceptibilities vary


  • P. alcalifaciens

  • P. rettgeri

  • P. rustigianii

  • P. stuartii

UTI, wound infection, bacteraemia

β‎-Lactams, aminoglycosides, fluoroquinolones

Susceptibilities vary. P. alcalifaciens has been associated with gastroenteritis

[Pseudomonas acidivorans—see Delftia acidivorans]


  • P. aeruginosa

  • P. alcaligenes

  • P. chlororaphis

  • P. fluorescens

  • P. mendocina

  • P. monteilii

  • P. mosselii

  • P. otitidis

  • P. pertocinogena

  • P. pseudalcaligenes

  • P. putida

  • P. stutzeri

Bacteraemia, UTI, wound infection, abscesses, septic arthritis, conjunctivitis, endocarditis, meningitis, otitis

Ureidopenicillins, aminoglycosides, ceftazidime, fluoroquinolones, carbapenems

Nosocomial infections associated with invasive devices in debilitated patients. Nosocomial outbreaks reported. May be multiresistant

[Pseudomonas cepacia—see Burkholderia cepacia]

[Pseudomonas diminuta—see Brevundimonas diminuta]

[Pseudomonas mallei—see Burkholderia mallei]

[Pseudomonas maltophilia—see Stenotrophomonas maltophilia]

[Pseudomonas mesophilica—see Methylobacterium mesophilicum]

P. luteola (Chryseomonas luteola)

Bacteraemia, endocarditis, CAPD peritonitis

Ureidopenicillins, ceftazidime, ciprofloxacin, aminoglycosides

P. oryzihabitans (Flavimonas oryzihabitans)

Septicaemia, eye infection, CAPD peritonitis

Ampicillin, tetracycline, gentamicin, cefotaxime

[Pseudomonas paucimobilis—see Sphingomonas paucimobilis]

[Pseudomonas pickettii—see Ralstonia pickettii]

[Pseudomonas pseudomallei—see Burkholderia pseudomallei]

[Pseudomonas putrefaciens—see Shewanella putrefaciens]

[Pseudomonas terrigena—see Comamonas terrigena]

[Pseudomonas testosteroni—see Comamonas testosteroni]

[Pseudomonas vesicularis—see Brevundimonas vesicularis]


P. autotrophica (Amycolata autotrophica)

Role as pathogen uncertain


P. alactolyticus

Periodontal disease, wound infection, abscesses

Penicillin, clindamycin, chloramphenicol


  • P. immobilis

  • P. phenylpyruvicus (Moraxella phenylpyruvica)

Meningitis, bacteraemia, eye infection

Penicillins, aminoglycosides, chloramphenicol



R. aquatilis

UTI, septicaemia


Immunocompromised patients


  • R. insidiosa

  • R. mannitolilytica

  • R. pickettii (Pseudomonas pickettii)

  • R. taiwanensis

Meningitis, peritonitis, bacteraemia, UTI, pulmonary infection

Co-trimoxazole, imipenem, ceftazidime, quinolones

Raoultella (Klebsiella)

  • R. ornithinolytica

  • R. planticola

  • R. terrigena

Bacteraemia, UTI, surgical sepsis, pancreatitis

Cephalosporins, carbapenems, aztreonam, quinolones, aminoglycosides

β‎-Lactamase producers. Associated with histamine (scombrotoxin) fish poisoning


R. bacterium

Pneumonia, pericarditis

Proposed name does not have standing in nomenclature


R. equi (Corynebacterium equi)

Bacteraemia, osteomyelitis, lung abscesses

Vancomycin, erythromycin, aminoglycosides

In immunocompromised patients, including AIDS


  • R. africae

  • R. akari

  • R. australis

  • R. conorii

  • R. felis

  • R. honei

  • R. japonica

  • ‘R. mongolotimonae’

  • R. prowazekii

  • R. rickettsiae

  • R. sibirica

  • R. slovaca

  • R. typhi

Rickettsial spotted fever, tick typhus, tick-bite fever, rickettsialpox


Transmitted by arthropods. Agents of Astrakhan fever, Israeli tick typhus, and Thai tick typhus await designation of scientific names. Other Rickettsia spp. are of uncertain clinical significance


  • R. cervicalis

  • R. gilardii ssp.

  • gilardii

  • R. gilardi ssp.

  • rosea

  • R. mucosa

Bacteraemia, wound infection, peritonitis

Aminoglycosides, imipenem, ciprofloxacin, ticarcillin-clavulanate

[Roseomonas fauriae—see Azospirillum brasilense]


R. dentocariosa

Endocarditis, abscesses

Penicillin and gentamicin

R. mucilaginosa (Micrococcus mucilaginosus) (Stomatococcus mucilaginosus)

Endocarditis, meningitis, neutropenic sepsis, necrotizing fasciitis

Glycopeptides, imipenem, rifampicin, ceftriaxone


  • R. flavefaciens

  • R. hansenii (Streptococcus hansenii)

  • R. luti

  • R. productus (Peptostreptococcus productus)

Abdominal sepsis, abscesses




  • S. bongori

  • S. choleraesuis ssp. arizonae

  • S. choleraesuis ssp. choleraesuis

  • S. choleraesuis ssp. diarizonae

  • S. choleraesuis ssp. houtenae

  • S. choleraesuis ssp. indica

  • S. choleraesuis ssp. salamae

  • S. enteritidis

  • S. paratyphi

  • S. subterranea

  • S. typhi

  • S. typhimurium

  • S. enterica ssp. arizonae

  • S. enterica ssp. diarizonae

  • S. enterica ssp. enterica

  • S. enterica ssp. houtenae

  • S. enterica ssp. indica

  • S. enterica ssp. salamae

  • S. subterranea

Gastroenteritis, enteric fever, osteomyelitis

β‎-Lactams, fluoroquinolones, chloramphenicol

Salmonella nomenclature is complicated by the existence of two sets of names, both of which have standing in nomenclature. Both sets of names are listed in the table. The first scheme listed is perhaps more helpful for clinicians because it treats the clinically important taxa S. typhi (the agent of typhoid fever), S. paratyphi, S. enteritidis, and S. typhimurium as species. In the alternative scheme, these taxa are treated as serovars of S. enterica ssp. enterica (e.g. Salmonella enterica ssp. enterica serovar Typhi) although as a form of shorthand the serovars can be written thus: Salmonella Typhi, Salmonella Paratyphi etc. As yet, S. subterranea has not been associated with infection


S. inopinata (Bifidobacterium inopinatum)

Dental caries


  • S. artemidis

  • S. dianae

  • S. flueggei

  • S. infelix

  • S. noxia

  • S. sputigena

Bacteraemia, lung abscess

Clindamycin, chloramphenicol, metronidazole

Malignancy and alcohol abuse reported as risk factors for infection

[Serpulina—see Brachyspira]


  • S. ficaria

  • S. fonticola

  • S. grimesii

  • S. liquefaciens

  • S. marcescens

  • S. odorifera

  • S. plymuthica

  • S. proteamaculans

  • S. quinivorans

  • S. rubidaea

Septicaemia, abscesses, burn infections, osteomyelitis

Imipenem, aminoglycosides, fluoroquinolones, ureidopenicillins, ceftazidime

Nosocomial outbreaks reported. May be multiresistant. At time of writing a proposal to use the name S. rubidae in place of S. rubidaea has not been validly published


  • S. algae

  • S. putrefaciens (Alteromonas putrefaciens) (Pseudomonas putrefaciens)

Abdominal sepsis, meningitis, bacteraemia

Ampicillin, cefotaxime, gentamicin, chloramphenicol

Debilitated patients


  • S. boydii

  • S. dysenteriae

  • S. flexneri

  • S. sonnei

Enteric infection

Co-trimoxazole, fluoroquinolones


S. negevensis

Bronchiolitis, pneumonia


S. exigua (Eubacterium exiguum)



S. sanguinegens (Leptotrichia sanguinegens = L. microbii)

Sphingobacterium (Flavobacterium)

  • S. multivorum

  • S. spiritivorum

  • S. thalpophilum

Bacteraemia, pulmonary infection

Co-trimoxazole, chloramphenicol, tetracycline, cephalosporins, quinolones

[Sphingobacterium mizutae—see Flavobacterium mizutaii]


  • S. parapaucimobilis

  • S. paucimobilis (Pseudomonas paucimobilis)

  • S. sanguinis (S. sanguis)

  • S. yanoikuyae

Septicaemia, UTI, wound infections, CAPD peritonitis

Ceftazidime, aminoglycosides

Nosocomial infections


‘S. minus’

Rat-bite fever


Streptobacillus moniliformis is also a rat-bite fever agent. The name ‘Spirillum minus’ does not have standing in nomenclature


  • S. aureus

  • S. auricularis

  • S. capitis capitis

  • S. capitis ureolyticus

  • S. caprae

  • S. cohnii cohnii

  • S. cohnii urealyticus

  • S. delphini

  • S. epidermidis

  • S. equorum

  • S. gallinarum

Bacteraemia, wound infection, endocarditis, catheter-related sepsis, UTI, toxic shock syndrome, food poisoning, eye infection, osteomyelitis

Glycopeptides, β‎-lactams, aminoglycosides, tetracycline, macrolides, rifampicin, fluoroquinolones, daptomycin, linezolid, fusidic acid, mupirocin

Staphylococci are surface commensals of humans and animals. S. aureus is also a major pathogen, causing focal and systemic sepsis, toxic shock syndrome, and food poisoning. S. epidermidis infection is often associated with foreign bodies (e.g. catheters and implants). S. saprophyticus causes UTI. S. lugdunensis is a rare cause of endocarditis. S. intermedius, S. hyicus, and others are from animals. Susceptibilities are variable but glycopeptide resistance is as yet rare

  • S. haemolyticus

  • S. hominis hominis

  • S. hominis novobiosepticius

  • S. hyicus

  • S. intermedius

  • S. lugdunensis

  • S. pasteuri

  • S. saccharolyticus

  • S. saprophyticus

  • S. schleiferi schleiferi

  • S. schleiferi coagulans

  • S. sciuri

  • S. simulans

  • S. vitulinus (S. pulvereri)

  • S. warneri

  • S. xylosus


  • S. maltophilia

  • (Pseudomonas maltophila)

  • (Xanthomonas maltophila)

  • (Stenotrophomonas africana)

Bacteraemia, meningitis, wound infection, UTI, pneumonia

Fluoroquinolones, chloramphenicol, co-trimoxazole

Resistance to aminoglycosides, penicillins, and carbapenems reported

[Stomatococcus mucilaginosus—see Rothia mucilaginosa]


S. moniliformis

Rat-bite fever, Haverhill fever

Penicillin, erythromycin

‘Spirillum minus’ is also a causative agent of rat-bite fever


S. acidominimus

Pneumonia, pericarditis, meningitis


From cattle

  • S. agalactiae

  • S. canis

  • S. dysgalactiae dysgalactiae

  • S. dysgalactiae equisimilis

  • S. equi equi

  • S. equi zooepidemicus

  • S. iniae (S. shiloi)

  • S. porcinus

  • S. pseudoporcinus

  • S. pyogenes

  • S. urinalis

Pharyngitis, bacteraemia, pyogenic infection, necrotizing infection, septic arthritis, UTI, glomerulonephritis, meningitis

β‎-Lactams, macrolides

S. pyogenes (Lancefield group A), S. agalactiae (group B), and S. dysgalactiae equisimilis (groups C and G) are commensals and pathogens of humans. S. iniae is from fish. Others are from mammals

  • S. anginosus

  • S. constellatus constellatus

  • S. constellatus pharyngis

  • S. intermedius

Abscesses, bacteraemia, endocarditis, pharyngitis

β‎-Lactams, macrolides

Often termed ‘S. milleri’ or microaerophilic streptococci. From human oral flora

  • S. equinus (S. bovis)

  • S. gallolyticus ssp. gallolyticus

  • S. gallolyticus ssp. pateurianus

  • S. infantarius ssp. coli

  • S. infantarius ssp. infantarius

  • S. lutetiensis

  • S. pasteurianus

Endocarditis, CAPD peritonitis

β‎-Lactams (plus gentamicin for endocarditis)

Intestinal streptococci from animals and humans. Some taxonomic problems relating to this group (the ‘bovis’ streptococci) await resolution

  • S. criceti

  • S. mutans

  • S. ratti

  • S. sobrinus

Dental caries, endocarditis


From the tooth-surface flora of humans and mammals

  • S. cristatus

  • S. gordonii

  • S. massiliensis

  • S. mitis

  • S. oralis

  • S. parasanguinis

  • S. salivarius

  • S. sanguinis

  • S. sinensis

  • S. vestibularis

Bacteraemia, endocarditis, wound infection

β‎-Lactams, macrolides

Human oral streptococci including taxa sometimes known as the ‘viridans streptococci’

  • S. pneumoniae

  • S. pseudopneumoniae

Pneumonia, bacteraemia, sinusitis, peritonitis, otitis, conjunctivitis

β‎-Lactams, macrolides, chloramphenicol

Penicillin resistance locally common

S. suis



Associated with pig contact


  • S. albus

  • S. anulatus

  • ‘S. paraguayensis’

  • S. somaliensis


Dapsone, co-trimoxazole

  • S. bikiniensis

  • S. griseus

Bacteraemia, abscess, pericarditis, endocarditis

Vancomycin, tetracycline, penicillin

Treatment options poorly defined


S. dextrinosolvens

Bacteraemia, pneumonia


From faecal and gingival flora


S. wadsworthensis

Appendicitis, peritonitis, abscesses, osteomyelitis

Amoxicillin/clavulanate, ticarcillin/clavulanate, meropenem, ceftriaxone

One-third of isolates reported to be metronidazole resistant


S. indologenes (Kingella indologenes)

Endocarditis, eye infection

Penicillin (plus gentamicin for endocarditis



T. forsythensis (T. forsythia, T. forsythus)

Endodontic infection

[Tatlockiamaceachernii—see Legionella maceachernii]

[Tatlockia micdadei—see Legionella micdadei]


T. ptyseos

Bacteraemia, UTI

Ampicillin, tetracycline, chloramphenicol, gentamicin

The significance of isolates from sputum is unclear


T. praeacuta (Bacteroides praeacuta) (Clostridium hastiforme)




T. guamensis


Co-trimoxazole, gentamicin, chloramphenicol

Role as possible pathogen uncertain


  • T. amylovorum

  • T. denticola

  • T. lecithinolyticum

  • T. maltophilum

  • T. medium

  • T. parvum

  • T. pectinovorum

  • T. putidum

  • T. scoliodontum

  • T. socranskii

  • ‘T. vincentii’

Associated with periodontal disease. Role as potential pathogens unclear

‘T. carateum’



Name does not have standing in nomenclature

  • T. minutum

  • ‘T. phagedenis’’

  • ‘T. refringens’

From genital flora. Considered nonpathogenic but have been isolated from genital lesions

  • T. pallidum

  • ‘T. pallidum endemicum’



‘T. pallidum endemicum’ is the agent of nonvenereal endemic syphilis

T. pertenue (‘T. pallidum pertenue’)




T. whipplei (T. whippelii)

Whipple’s disease

Uncultured organism


  • T. inchonensis

  • T. paurometabola

  • T. pulmonis

  • T. strandjordii (T. strandjordae)

  • T. tyrosinosolvens

Septicaemia, cutaneous infections, lung infections

β‎-Lactam (plus aminoglycoside)

Line-associated infections in debilitated patients. T. pulmonis isolated from the sputum of a tuberculosis patient


T. otitidis

Otitis, cervical abscess

Glycopeptides, β‎-lactams



  • U. parvum

  • U. urealyticum


Tetracycline, erythromycin



V. fluvialis

Ampicillin, vancomycin cefotaxime

Possible role as pathogen poorly defined


V. cambriensis



  • V. atypical

  • V. dipsar

  • V. montpellierensis

  • V. parvula

Abscesses, bacteraemia



V. alginolyticus

Wound infection, ear infection

Chloramphenicol, tetracycline

Infection associated with aquatic exposure

V. cholerae



V. cincinnatiensis


Moxalactam, chloramphenicol, cephalosporins

Risk factors for infection not defined

[Vibrio damsela—see Photobacterium damselae]

  • V. fluvialis

  • V. furnissii

  • V. metschnikovii

  • V. mimicus

  • V. parahaemolyticus

Diarrhoea, septicaemia

Tetracycline, chloramphenicol

Infection associated with ingestion of contaminated water or shellfish

V. harveyi (V. carchariae)

Wound infection

Cephalosporins, chloramphenicol, gentamicin

Infection associated with shark bite. May require debridement

[Vibrio hollisae—see Grimontia hollisae]

V. vulnificus

Wound infection, septicaemia, meningitis, endometritis

Tetracycline, penicillins, gentamicin, chloramphenicol

Risk factors include aquatic exposure and penetrating fish injury. May require debridement



W. falsenii

Bacteraemia, wound infection


W. virosa


Imipenem, ampicillin

From vaginal flora

[Weeksella zoohelcum—see Bergeyella zoohelcum]


W. confusa



W. muralis

Pulmonary infection


W. chitiniclastica



Associated with myiasis


W. sp.



Endosymbiont of filarial nematodes

[Wolinella curva—see Campylobacter curvus]

[Wolinella recta—see Campylobacter rectus]



X. campestris


[Xenorhabdus luminescens—see Photorhabdus luminescens]



  • Y. aldovae

  • Y. bercovieri

  • Y. enterocolitica

  • Y. frederiksenii

  • Y. intermedia

  • Y. kristensenii

  • Y. mollaretii

  • Y. pseudotuberculosis

  • Y. rohdei

Enterocolitis, soft tissue infections, mesenteric lymphadenitis

Tetracycline, chloramphenicol, aminoglycosides, fluoroquinolones, cephalosporins

Medical significance of manyYersinia spp. is unclear. Antibiotic treatment is not indicated for uncomplicated enteric infection

Y. pestis


Streptomycin, tetracycline


Y. regensburgei (Koserella trabulsii)

Bacteraemia, wound infection

Aminoglycosides, chloramphenicol

CAPD, continual ambulatory peritoneal dialysis; sp. species; ssp. subspecies; UTI, urinary tract infection.