Enterobacter aerogenes (aerobacter aerogenes) in Cats (Felis) | Vetlexicon
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Enterobacter aerogenes (aerobacter aerogenes)

ISSN 2398-2950

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Synonym(s): E. aerogenes

Introduction

Classification

Taxonomy

  • Family: Enterobacteriaceae.
  • Genus: Enterobacter.
  • Tribe: Klebsiellae.
  • Species: aerogenes

Etymology

  • Gk: entero - intestine; bacter - a small rod; aerogenes - gas-producing.

Distribution

  • Worldwide.

Significance

  • Opportunistic pathogen; occasionally causes infection in animals.
  • Found in soil, dairy products, water, sewage and in gastrointestinal tract.

Active Forms

Active Form 1

Morphology

  • 24 hours incubation on blood agar   →   2-3 mm, non-hemolytic, round and shiny colonies (very mucoid on primary isolation due to the presence of a large capsule around individual cells).

Taxonomy

  • Distinguish from Klebsiella and Serratia by a combination of:
    • Motility: motile (unlike non-motile Klebsiella).
    • Lactose fermenter (but colonies only pale pink on MacConkey agar).
    • Decarboxylases.
    • Voges-Proskauer reaction .
    • Fermentation of several carbohydrates.
    • Urease production.
    • Gram's staining : negative, medium-sized, non-sporing rods.
    • Aerobic: facultatively anaerobic.
    • Catalase test: positive.
    • Oxidase test: negative.

Color

  • Grayish on blood agar.

Tolerances

Humidity
  • Survive many months in moist shaded areas, eg manure.
Ultraviolet
  • Susceptible to sunlight and to drying.
Other
  • Killed by pasteurization.

Development

Reproduction
  • Binary fission.
  • Non-spore-forming.
Longevity
  • Can survive for months in a moist, shaded environment.

Resting Forms

Clinical Effects

Epidemiology

Lifecycle

  • Reproduces by binary fission in anaerobic or aerobic environment.
  • Does not form spores.
  • May undergo conjugation with other enterobacteria, with transfer of plasmids.

Transmission

  • Exogenous or endogenous infection.
  • Often following wound contamination.

Pathological effects

  • Trauma   →   triggers endogenous (opportunistic) infection   →   pathogenicity.

Diseases

  • Cattle: coliform mastitis.
  • Horse: uterine infections.
  • Pig: occasionally part of mastitis-metritis-agalactia (MMA) syndrome.

Other host effects

  • Usually commensal found in water, soil, sewage and gastrointestinal tract.
  • Isolated from tracheal swabs and lungs in healthy dogs.

Control

Control via chemotherapies

Usual susceptibility

Resistance

  • Cephalothin .
  • Ampicillin Ampicillin.
    Antibiotic resistance is a problem as in otherEnterobacteriaceae.

Vaccination

  • None.

Diagnosis

Useful samples

  • Pus.
  • Infected tissue.

Specimen storage

  • If they cannot be processed within 2 hours, samples should be stored at 4°C.

Transport of samples

Laboratory diagnosis

  • Gram-staining: gram-negative rods.

Culture

  • Good under aerobic or anaerobic conditions.
  • Good on blood agar.
  • Selective media containing bacteriostatic dyes inhibit most gram-positive bacteria, eg brilliant green as in brilliant green agar or surface-acting compounds such as bile salts as in MacConkey agar or deoxycholate agar.

Identification methods

  • Motility and colonial morphology on various selective media.
  • IMViC test: -/-/+/+ .
  • API 20E commercial strip is a more expensive, less time-consuming method.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Burrows G E, Morton R J & Fales W H (1993) Microdilution antimicrobial susceptibilities of selected gram-negative veterinary bacterial isolates. J Vet Diagn Invest (4), 541-547 PubMed.
  • Russell R G, Slattum M M, Abkowitz J (1988) Filamentous bacteria in oral eosinophilic granulomas of a cat. Vet Pathol 25 (3), 249-250 PubMed.
  • Dow S W, Jones R L, Adney W S (1986) Anaerobic bacterial infections and response to therapy in dogs and cats - 36 cases (1983-1985). JAVMA 189 (8), 930-934 PubMed.
  • Hatton R W (1985) Unfamiliar bacteria isolated from cats. Vet Rec 117 (4), 94 PubMed.