engleski

Antimicrobial resistance of Yersinia enterocolitica isolated from tonsils of pigs produced on family farms

Yersinia enterocolitica is one of the most important biological hazards in public health closely related to pigs and pork meat production and consumption. Tonsils represent the most important source of meat contamination with pathogen during the slaughtering process. The aim of this work was to investigate the prevalence of Y. enterocolitica in tonsils of pigs produced on family farms and slaughtered in the same approved local slaughterhouse, as well as the antimicrobial resistance of isolated strains. The tonsils of 48 pigs, which came from 14 family farms, were sampled on the slaughter line. The presence of Y. enterocolitica in tonsils was determined by using the HRN EN ISO 10273:2017 method and the identification of the susceptible colonies by means of MALDITOF MS. The susceptibility of the isolates was tested against eleven antibiotics: levofloxacin (5 μg), ciprofloxacin (5 μg), ampicillin (10 μg), cephalothin (30 μg), cefotaxime (30 μg), tetracycline (30 μg), nalidixic acid (30 μg), ceftazidime (30 μg), trimethoprim/sulfamethoxazole (25 μg), chloramphenicol (30 μg) and streptomycin (10 μg) by using the disc diffusion method. The interpretation of the results based on the size of inhibition zones was carried out according to the CLSI criteria for enterobacteria. Morphologically typical colonies on CIN agar (small, bull-eye) were found in 26 tonsils samples (54% ; n = 48) from pigs produced on 9 farms (64.28% ; n = 14) and all were confirmed as Yersinia enterocolitica by MALDI-TOF MS. All isolates showed resistance to the same two antibiotics, ampicillin and cephalothin, while only 1 strain was additionally resistant to streptomycin, trimethoprim/sulfamethoxazole, ceftazidime and nalidixic acid. The results indicate a low level of Y. enterocolitica resistance to clinically relevant antimicrobial agents in pigs from Croatian family farms. However, the wide presence of pathogen in the pig population increases the risk of meat cross-contamination during the slaughter process.

antimicrobial resistance ; pigs ; tonsils ; lymph nodes ; family farms

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