Occurrence of Yersinia enterocolitica O:3, Listeria monocytogenes O:4 and thermophilic Campylobacter spp. in slaughter pigs and carcasses in Trinidad

Abstract

Pigs slaughtered at an abattoir in Trinidad were sampled for the occurrence of Yersinia, Listeria and Campylobacter at different sites. The antibiograms of Yersinia isolates were also determined. Of 141 samples each of rectal and tongue swabs taken, 23(16·1%) and 9(6·4%) were positive for Y. enterocolitica compared to 11(7·3%) of 150 tonsillar samples yielding the organism. Rectal swabs had a statistically significantly ( P ≤ 0·05, x 2 ) higher frequency of isolation than tongue or tonsillar swabs. All 43 isolates of Y. enterocolitica were serotype O:3 biotype 4. From a total of 139 rectal swabs cultured for thermophilic Campylobacter , 75(51·8%) were C. coli and 3(2·2%) were positive for C. jejuni . The difference was statistically significant ( P ≤ 0·001; x 2 ). Carcass swabs also yielded significantly more C. coli , 27(17·4%) than C. jejuni , 4(2·6%) of 155 samples cultured. Seven (5·0%) of 139 rectal swabs tested were positive for Listeria monocytogenes while only 3(1·9%) of 155 carcass samples yielded the organism but the difference was not statistically significant ( P ≥ 0·05; x 2 ). Nine of 10 isolates of L. monocytogenes were serotype 4 while one was serotype 1. Resistance of the 43 isolates of Y. enterocolitica was highest to penicillin (100·0%), neomycin (100·0%) but least to gentamycin (2·3%) and sulfamethoxazole/trimethoprim (0·0%). It was concluded that Y. enterocolitica serotype O:3, biotype 4 is predominant in pigs in Trinidad and the isolation of L. monocytogenes , particularly serotype 4, and C. coli and C. jejuni from pork carcasses may pose a health risk to consumers.