Frequency, antimicrobial susceptibility and adherence patterns of Salmonella enterica isolated from chicken meat, beef and pork from Mexico City

Background: Food of animal origin is often involved in salmonellosis outbreaks. Aim: To evaluate the frequency of Salmonella enterica in chicken, beef and pork ground meat (a total of 2,592 samples) obtained from travelling markets and supermarkets at the Iztapalapa area of Mexico City, in order to determine the antimicrobial susceptibility and adherence capacity of isolated strains. Methods: Isolation of S. enterica was carried out according to the BAM-FDA, the microbial susceptibility according with CLSI and adherence assay on HEp-2 cell line according with Baffone et al., 2001. Results: S. enterica was isolated from 511 of all the analyzed samples (19.7%), from which 244 (47.7%), 152 (29.7%) and 115 (22.5%) corresponded to chicken, beef and pork ground meat, respectively. The highest frequency of resistance of S. enterica to antimicrobials was to ampicillin and chloramphenicol in chicken, perfloxacin and ampicillin in beef and carbenicillin, ampicillin, chloramphenicol, cefotaxime and perfloxacin in pork. Ninety percent of the strains showed an aggregative adherence pattern on HEp-2 cells. Conclusion: The frequency of S. enterica on meat products is high, which is the reason why a proper cooking of these ground meats is important in order to reduce the risk of acquiring salmonellosis.