Serratia spp in Horses (Equis) | Vetlexicon
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Serratia spp

ISSN 2398-2977

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Introduction

Classification

Taxonomy

  • Family:Enterobacteriaceae.
  • Genus:serratia.

Etymology

  • Named after Serafino Serrati, an Italian physicist.

Distribution

  • Worldwide.

Significance

  • Environmental organism.
  • May cause mastitis in cattle, infections in reptiles, and septicemia in chickens and in immunosuppressed mammals.

Active Forms

Active Form 1

Morphology

  • Colonies observed after overnight growth.
  • Usually opaque and may be white, pink or red due to pigment production.
  • The pigment prodigiosin is produced by various strains; best produced at 20-35°C.
  • The pigment pyrimime produced by some strains ofSerratia marsescensturns the agar pink.

Taxonomy

  • Gram-negative, straight rods with round ends; motile; facultatively anaerobic; catalase positive; oxidase negative.

Color

  • White, pink or red on blood or nutrient agar.

Not to be confused with pink, lactose-fermenting colonies on lactose containing agar, eg MacConkey.

Tolerances

Temperature
  • Killed by pasteurization.
Humidity
  • Damp conditions aid survival.
Ultraviolet
  • Killed by sunlight.

Development

Growth
  • Facultative anaerobe.
  • Utilizes simple substrates for growth.
  • Under anaerobic conditions, depends on fermentable carbohydrate.
  • Under aerobic conditions, can metabolize organic acids, amino acids or carbohydrates.
Reproduction
  • Binary fission.
  • May undergo conjugation with exchange of plasmids.
Longevity
  • Can survive for several months in moist, shaded environments.

Resting Forms

Clinical Effects

Epidemiology

Habitat

  • Environmental organism, opportunistic pathogen.

Lifecycle

  • Multiplies in damp, shaded environments by binary fission.
  • Multiplies in the immunocompromised host.
  • May exchange plasmids with otherEnterobacteriaceae.

Transmission

  • Contamination of wounds or other compromised sites.
  • Cause of nosocomial infections following environmental contamination.

Pathological effects

  • Associated with infection in immunosuppressed animals and humans.
  • Mastitis in cows.
  • Septicemia in chickens and immunosuppressed mammals, eg foals.
  • Infections in reptiles.

Control

Control via chemotherapies

Diagnosis

Useful samples

Specimen storage

  • Refrigerate specimens unless they can be processed within 2 h of collection.

Transport of samples

  • Use transport media such as Stuart, Amies, Cary-Blair or buffered glycerol-saline.
  • Package according to Department of Transportation regulations   Transportation of diagnostic specimens  .

Field diagnosis

  • Gram-stained smears show gram-negative rods.

Laboratory diagnosis

  • Pigment-producing strains show characteristic colored colonies.
  • Biochemical tests or API 20E strip.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Jores J et al (2004) Isolation of Serratia marcescens from an equine abortion in Germany. Vet Rec 154 (8), 242-244 PubMed.
  • Ewart S et al (1992) Serratia marcescens endocarditis in a horse. JAVMA 200 (7), 961-963 PubMed.
  • Young D R et al (1989) Serratia marcescens septicemia associated with infusion of an amino acid solution in two horses. JAVMA 195 (3), 340-342 PubMed.
  • Rigg D L et al (1987) Marsupialization of an abdominal abscess caused by Serratia marcescens in a mare. JAVMA 191 (2), 222-224 PubMed.
  • Colahan P T et al (1984) Serratia spp infection in 21 horses. JAVMA 185 (2), 209-211 PubMed.
  • Shaftoe S (1984) Serratia marcescens septicemia in a neonatal Arabian foal. Equine Vet J 16 (4), 389-392 PubMed.
  • Fox J G, Beaucage C M, Folta C A & Thornton G W (1981) Nosocomial transmission of Serratia marcescens in a veterinary hospital due to contamination by benzalkonium chloride. J Clin Microbiol 14 (2), 157-60 PubMed.