Hunted Wild Boars in Sardinia: Prevalence, Antimicrobial Resistance and Genomic Analysis of <i>Salmonella</i> and <i>Yersinia enterocolitica</i>

oleh: Giuliana Siddi, Francesca Piras, Maria Pina Meloni, Pernille Gymoese, Mia Torpdahl, Maria Fredriksson-Ahomaa, Mattia Migoni, Daniela Cabras, Mario Cuccu, Enrico Pietro Luigi De Santis, Christian Scarano

Format: Article
Diterbitkan: MDPI AG 2023-12-01

Deskripsi

The objective of this investigation was to evaluate <i>Salmonella</i> and <i>Yersinia enterocolitica</i> prevalence in wild boars hunted in Sardinia and further characterize the isolates and analyse antimicrobial resistance (AMR) patterns. In order to assess slaughtering hygiene, an evaluation of carcasses microbial contamination was also carried out. Between 2020 and 2022, samples were collected from 66 wild boars hunted during two hunting seasons from the area of two provinces in northern and central Sardinia (Italy). Samples collected included colon content samples, mesenteric lymph nodes samples and carcass surface samples. <i>Salmonella</i> and <i>Y. enterocolitica</i> detection was conducted on each sample; also, on carcass surface samples, total aerobic mesophilic count and <i>Enterobacteriaceae</i> count were evaluated. On <i>Salmonella</i> and <i>Y. enterocolitica</i> isolates, antimicrobial susceptibility was tested and whole genome sequencing was applied. <i>Salmonella</i> was identified in the colon content samples of 3/66 (4.5%) wild boars; isolates were <i>S. enterica</i> subs. <i>salamae</i>, <i>S.</i> ser. <i>elomrane</i> and <i>S. enterica</i> subs. <i>enterica</i>. <i>Y. enterocolitica</i> was detected from 20/66 (30.3%) wild boars: in 18/66 (27.3%) colon contents, in 3/66 (4.5%) mesenteric lymph nodes and in 3/49 (6.1%) carcass surface samples. In all, 24 <i>Y. enterocolitica</i> isolates were analysed and 20 different sequence types were detected, with the most common being ST860. Regarding AMR, no resistance was detected in <i>Salmonella</i> isolates, while expected resistance towards <i>β</i>-lactams (<i>blaA</i> gene) and streptogramin (<i>vatF</i> gene) was observed in <i>Y. enterocolitica</i> isolates (91.7% and 4.2%, respectively). The low presence of AMR is probably due to the low anthropic impact in the wild areas. Regarding the surface contamination of carcasses, values (mean ± standard deviation log<sub>10</sub> CFU/cm<sup>2</sup>) were 2.46 ± 0.97 for ACC and 1.07 ± 1.18 for <i>Enterobacteriaceae</i>. The results of our study confirm that wild boars can serve as reservoirs and spreaders of <i>Salmonella</i> and <i>Y. enterocolitica</i>; the finding of <i>Y. enterocolitica</i> presence on carcass surface highlights how meat may become superficially contaminated, especially considering that contamination is linked to the conditions related to the hunting, handling and processing of game animals.