Canis ISSN: 2398-2942

Bacteroides fragilis

Synonym(s): B. fragilis

Contributor(s): Richard Walker

Introduction

Classification

Taxonomy

  • Family: Bacteroidaceae.
  • Genus: Bacteroides.
  • Species: fragilis.

Etymology

  • Gr: bacterum - staff or rod; idus - form or shape.
  • L: fragilis - fragile (referring to the brittle colonies that may form).

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Clinical Effects

Epidemiology

Habitat

  • Part of normal flora of gastrointestinal tract and mucous membranes.

Lifecycle

  • Multiplies in anaerobic environments such as devitalized tissue.
  • Does not form spores.

Transmission

  • Opportunists - invade skin, mucosa and underlying tissues following damage.

Pathological effects

  • Trauma, necrosis and ischemia → decreased redox potential → multiplication of B. fragilis and possibly → focal multiplication of facultative anaerobes.

Other Host Effects

  • Part of the normal flora of gastrointestinal tract and mucous membranes.

Control

Control via chemotherapies

  • Some strains are resistant to penicillin and some cephalosporins.
  • Clavulanic acid - amoxicillin or metronidazole usually effective.
    All obligate anaerobes are resistant to aminoglycosides.
  • Metronidazole Metronidazole active against most B. fragilis.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Dow S W & Jones R L (1987) Anaerobic infections Part 1 - Pathogenesis and clinical significance. Comp Cont Ed Pract Vet 9, 711.
  • Dow S W et al (1986) Anaerobic bacterial infections and response to therapy in dogs and cats - 36 cases (1983-1985). JAVMA 189, 930.
  • Hirsch D C et al (1985) Changes in prevalence and susceptibility of obligate anaerobes in clinical veterinary practice. JAVMA 186, 1086.

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