Department of Veterinary Medicine, University of Sassari, Via Vienna 2, 07100 Sassari, Italy.
Department of Veterinary Medicine, University of Sassari, Via Vienna 2, 07100 Sassari, Italy.
Int J Food Microbiol. 2018 Oct 20;283:1-6. doi: 10.1016/j.ijfoodmicro.2018.06.010. Epub 2018 Jun 13.
The aims of the present study were to determine Yersinia enterocolitica prevalence in finishing pigs and piglets at slaughter and to characterize the isolates in terms of bioserotype, virulence profile, antimicrobial susceptibility and genetic diversity. During the years 2013-2014, nine pig slaughterhouses placed in Sardinia (Italy) were visited twice, in order to collect animal samples and scalding water. Overall, 609 samples respectively of tonsils (126), colon content (161), mesenteric lymph nodes (161) and carcass surfaces (161) were collected from 126 finishing pigs and 35 piglets. Moreover, 18 scalding water samples were collected. Samples were analyzed for the detection of Y. enterocolitica according to ISO 10273-2003 standard (with some modifications). With regard to finishing pigs, Y. enterocolitica was detected in 11.9% of colon content samples, 3.2% of tonsils and 2.4% of lymph nodes. In piglets, Y. enterocolitica prevalence was 8.6% in colon content and 2.8% lymph nodes samples. Y. enterocolitica was not detected from carcass surface samples of both finishing pigs and piglets and from scalding water samples. Isolates were bio- and serotyped, tested for the presence of four virulence genes by PCR (ail, ystA, ystB and inv) and for antimicrobial resistance by disc-diffusion method. Among 47 confirmed isolates, 33 (70.2%) belonged to bio-serotype 4:O3, 7 (14.9%) to bio-serotype 2/O:5 and 7 (14.9%) to bio-serotype 1A. Bio-serotype 1A was detected only in isolates of piglets' samples. In bio-serotype 4/O:3 isolates the most common virulence genes were ystA (97.0%), ail (84.8%) and inv (78.8%). In bio-serotype 2/O:5, ail, inv and ystA genes were detected in all of the isolates. All bio-serotype 1A isolates were ystB positive (lacking ail, inv and ystA). All isolates were susceptible to cefotaxime, ceftazidime, chloramphenicol, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, sulphonamide, tetracycline and trimethoprim-sulphametoxazole. Resistances to ampicillin and cefalothin were the most common (100%), followed by amoxicillin/clavulanic acid (83.0%) and streptomycin (4.3%). Resistance to amoxicillin/clavulanic acid was detected in 57% of bio-serotype 4/O:3 isolates, 71% of bio-serotype 1A and 100% of bio-serotype 2/O:5 isolates. Two bio-serotype 4/O:3 isolates (6%) were resistant to streptomycin. Thirty-two pathogenic Y. enterocolitica isolates were tested by NotI-PFGE, which identified 5 patterns among bio-serotype 4/O:3 isolates and 2 patterns among bio-serotype 2/O:5 isolates. This study provides epidemiological data about human pathogenic Y. enterocolitica and highlight the role of pigs as a potential source of infection for the consumers in Sardinia.
本研究的目的是确定屠宰场育肥猪和仔猪中肠炎耶尔森菌的流行情况，并从生物血清型、毒力谱、药敏谱和遗传多样性等方面对分离株进行特征描述。2013-2014 年，在意大利撒丁岛的 9 个屠宰场进行了两次访问，以收集动物样本和烫水。总共从 126 头育肥猪和 35 头仔猪中采集了分别为 609 个扁桃体（126 个）、结肠内容物（161 个）、肠系膜淋巴结（161 个）和胴体表面（161 个）的样本。此外，还采集了 18 个烫水样本。根据 ISO 10273-2003 标准（略有修改）对样本进行了肠炎耶尔森菌检测。对于育肥猪，在 11.9%的结肠内容物样本、3.2%的扁桃体和 2.4%的淋巴结中检测到肠炎耶尔森菌。在仔猪中，结肠内容物和淋巴结样本中肠炎耶尔森菌的流行率分别为 8.6%和 2.8%。未从育肥猪和仔猪的胴体表面样本以及烫水样本中检测到肠炎耶尔森菌。分离株进行了生物和血清学分型，通过 PCR（ail、ystA、ystB 和 inv）检测了 4 种毒力基因的存在情况，并通过纸片扩散法检测了抗生素耐药性。在 47 株确证的分离株中，33 株（70.2%）属于生物血清型 4:O3，7 株（14.9%）属于生物血清型 2/O:5，7 株（14.9%）属于生物血清型 1A。生物血清型 1A 仅在仔猪样本的分离株中检测到。在生物血清型 4/O:3 分离株中，最常见的毒力基因是 ystA（97.0%）、ail（84.8%）和 inv（78.8%）。在生物血清型 2/O:5 中，所有分离株均检测到 ail、inv 和 ystA 基因。所有生物血清型 1A 分离株均为 ystB 阳性（缺乏 ail、inv 和 ystA）。所有分离株均对头孢噻肟、头孢他啶、氯霉素、环丙沙星、恩诺沙星、庆大霉素、萘啶酸、磺胺类药物、四环素和甲氧苄啶-磺胺甲恶唑敏感。对氨苄西林和头孢噻吩的耐药性最为常见（100%），其次是阿莫西林/克拉维酸（83.0%）和链霉素（4.3%）。在 57%的生物血清型 4/O:3 分离株、71%的生物血清型 1A 和 100%的生物血清型 2/O:5 分离株中检测到对阿莫西林/克拉维酸的耐药性。有 2 株生物血清型 4/O:3 分离株（6%）对链霉素耐药。对 32 株致病性肠炎耶尔森菌分离株进行了 NotI-PFGE 检测，结果显示生物血清型 4/O:3 分离株有 5 种模式，生物血清型 2/O:5 分离株有 2 种模式。本研究提供了关于人类致病性肠炎耶尔森菌的流行病学数据，并强调了猪作为撒丁岛消费者潜在感染源的作用。
