Western
Meeting of Poultry
Clinicians and Pathologists
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Clinicians and Pathologists
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Isolation of More than One Type of Escherichia coli from Individual Cellulitis Lesions Brenda Allan & Susantha Gomis Veterinary Infectious Disease Organization
Cellulitis in broiler chickens is a subcutaneous lesion located mainly in the abdominal are. E. coli is the predominant microorganism isolated from cellulitis lesions, although other agents such as Pasteurella multocida, Pseudomonas aeruginosa, Enterobacter agglomerans, Proteus vulgaris, and Streptococcus dysgalactiae have also been isolate. In the fall of 1995, 110 birds with cellulitis from 9 flocks indifferent locations in Saskatchewan were sampled for bacteriological study. Isolation of E. coli from broilers condemned for cellulitis was conducted at Sunnyland Poultry Products, Wynyard, Saskatchewan, Canada. Broiler carcasses tentatively condemned for cellulitis, based on gross examination of the caudal abdominal skin for discoloration or thickening, after removing feathers were collected prior to evisceration of the internal organs and examined for cellulitis and other gross lesions. Bacterial cultures on blood and MacConkey agar were routinely conducted fromcellulitis lesion, pericardium, air sacs and lungs and any other gross lesion. Bacterial culture swabs from lesions were plated within 3-4 h of slaughtering of birds. In birds where only cellulitis lesions occurred, E. coli cultures derived from the cellulitis lesion were scraped directly off the original MacConkey agar plate and stored at –70oC in Brain Heart Infusion (Difco, Detroit, MI) with 25% Clycerol (BDH Inc. Toronto, Canada) fo further study. Frozen stocks were subcultured on MacConkey agar and after 18 hours 37oC the plates were examined for variation in colony morphology. If all the colonies appeared to be of the same morphology the cultures were discarded. If more than one colony type was present, individual representative colonies were restreaked on MacConkey agar. If the apparent differences in appearance were maintained after subculture, the individual colony types were frozen to provide a stable population for further study. Eight cultures yielded two colony types and one culture yielded three colony types. Using BBL Crystal Identification, it was determined that all the cultures but one were E. coli. In one case, one member of the pair was identified as Klebseilla pneumonia. This pair was excluded from further study. In no cases did both members of a pair yield the same biochemical profile. In the case of the three isolates from a single source, all three were different. All cultures were tested for their O and H antigens by the E. coli Reference Center, Pennsylvania State University. In all cases the serotyping results suggested that the pairs of bacteria were in fact different isolates. These data suggests that in some cases an individual cellulitis lesion may contain more than one type of E. coli. It is not clear the relative contribution of the individual isolates make to the occurrence of the cellulitis lesion. |
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