Pseudomonas aeruginosa isolated from Chinchilla - short communication - Dr. Costin Stoica
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The lab received 2 dead gray chinchillas (Chinchilla
lanigera), one young and one adult female, from a
small breeding farm. Reported mortality in the farm
was 5 dead out of 80 individuals. Death was rapid and
no clinical signs were observed.
Necropsy revealed in both cases intense white spotted
liver (picture 1). Same types of spotted areas was
observed on external side of the intestine (picture 2).
Bacteriology:
One blood agar and one Mac Conkey agar plate were
inoculated with liver samples and incubated 24 hours
at 37 ºC. On both plates from the adult female was
obtained a pure culture: on blood agar - wrinkled,
elongated, haemolytic colonies and on Mac Conkey
agar lactose negative colonies.
Morphological and biochemical properties of the strain:
Pigment production was investigated on Mueller-Hinton
agar. After 48 hours of incubation a green,
fluorescent, diffusible pigment appeared.
Anaerobic growth failed. Growth at 41 ºC, oxidase &
catalase positive.
Gram-negative rods.
TSI, MIU and Simmons results:
TSI - strictly aerobic, lactose-sucrose negative
MIU - growth failed
Simmons - citrate positive
Biochemical results on API 20 NE strip:
Nitrates & nitrites were reduced. Indole production,
glucose acidification, arginine dihydrolase, urease,
esculin & PNPG were negative. Gelatin hydrolysis was
positive. Assimilation of glucose, mannitol,
N-acetyl-glucosamine, gluconate, caprate, adipate,
malate & citrate were positive. Assimilation of
arabinose, mannose, maltose & phenyl-acetate were
negative.
API identified strain as Pseudomonas aeruginosa
99.9%.
With ABIS 6 online software result was Pseudomonas
aeruginosa 85% (with a question mark on the negative
arginine dihydrolase).
Antibiogram:
The isolated strain was sensible to Enrofloxacin, Gentamicin, Neomycin, Streptomycin, Kanamycin and resistant to
Lincomycin, Amoxicillin, Bacitracin, Sulphamethoxazole+Trimethoprim, Ampicillin, Trimethoprim, Penicillin,
Tetracycline.
Taking into consideration bacteriological and necropsy results we may conclude that the Pseudomonas aeruginosa
septicaemia was the main cause of death.
The pseudomonosis episode was stopped with Enrofloxacin treatment.
Image 2 - intestinal lesions
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(c) Costin Stoica