Identification of campylobacteria isolated from Danish broilers by phenotypic tests and species-specific PCR assays.
OBJECTIVE
To validate a phenotypic Campylobacter species identification method employed to identify campylobacters in broilers by comparison with campylobacterial species identification using various species-specific PCR analyses.


RESULTS
From a collection of 2733 phenotypically identified campylobacterial cultures, 108 Campylobacter jejuni cultures and 351 campylobacterial cultures other than Camp. jejuni were subjected to various species-specific PCR assays. On the basis of the genotypic tests, it was demonstrated that Camp. jejuni and Camp. coli constituted approx. 99% of all cultures, while other species identified were Helicobacter pullorum, Camp. lari and Camp. upsaliensis. However, 29% of the 309 Camp. coli cultures identified by phenotypic tests were hippurate-variable or negative Camp. jejuni cultures, whereas some Camp. lari cultures and unspeciated campylobacter cultures belonged to H. pullorum. It was also notable that 2-6% of the cultures were, in fact, mixed cultures.


CONCLUSIONS
The phenotypic identification scheme employed failed to appropriately differentiate Campylobacter species and particularly to identify the closely related species, H. pullorum.


CONCLUSIONS
Future phenotypic test schemes should be designed to allow a more accurate differentiation of Campylobacter and related species. Preferably, the phenotypic tests should be supplemented with a genotypic strategy to disclose the true campylobacterial species diversity in broilers.
Wainø
M
M
Department of Poultry, Fish and Fur Animals, Danish Veterinary Institute, Arhus N, Denmark. mwai@novonordisk.com
Bang
D D
DD
Lund
M
M
Nordentoft
S
S
Andersen
J S
JS
Pedersen
K
K
Madsen
M
M
D000818:Animals; D002167:Campylobacter / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D002645:Chickens; D004247:DNA / Q000032:analysis; D005838:Genotype; D006626:Hippurates / Q000378:metabolism; D006868:Hydrolysis; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods*; D013045:Species Specificity
D006626:Hippurates; D004247:DNA