Badul Sasha, Abia Akebe L K, Amoako Daniel G, Perrett Keith, Bester Linda A, Essack Sabiha Y
Antimicrobial Research Unit, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa.
Biomedical Resource Unit, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa.
Microorganisms. 2021 Apr 21;9(5):882. doi: 10.3390/microorganisms9050882.
Foodborne pathogens, including antibiotic-resistant species, constitute a severe menace to food safety globally, especially food animals. Identifying points of concern that need immediate mitigation measures to prevent these bacteria from reaching households requires a broad understanding of these pathogens' spread along the food production chain. We investigated the distribution, antibiotic susceptibility, molecular characterization and clonality of spp. in an intensive pig production continuum in South Africa, using the farm-to-fork approach. spp. were isolated from 452 samples obtained along the pig farm-to-fork continuum (farm, transport, abattoir, and retail meat) using the IDEXX Enterolert/Quanti-Tray 2000 system. Pure colonies were obtained on selective media and confirmed by real-time PCR, targeting genus- and species-specific genes. The susceptibility to antibiotics was determined by the Kirby-Bauer disk diffusion method against 16 antibiotics recommended by the WHO-AGISAR using EUCAST guidelines. Selected antibiotic resistance and virulence genes were detected by real-time PCR. Clonal relatedness between isolates across the continuum was evaluated by REP-PCR. A total of 284 isolates, consisting of 79.2% , 6.7% , 2.5% , 0.4% , and 11.2% other spp., were collected along the farm-to-fork continuum. The isolates were most resistant to sulfamethoxazole-trimethoprim (78.8%) and least resistant to levofloxacin (5.6%). No resistance was observed to vancomycin, teicoplanin, tigecycline and linezolid. displayed 44.4% resistance to quinupristin-dalfopristin. Also, 78% of the isolates were multidrug-resistant. Phenotypic resistance to tetracycline, aminoglycosides, and macrolides was corroborated by the presence of the M, , and B genes in 99.1%, 96.1%, and 88.3% of the isolates, respectively. The most detected virulence gene was E. Clonality revealed that . isolates belonged to diverse clones along the continuum with major REP-types, mainly isolates from the same sampling source but different sampling rounds (on the farm). isolates revealed a less diverse profile. The results suggest that intensive pig farming could serve as a reservoir of antibiotic-resistant bacteria that could be transmitted to occupationally exposed workers via direct contact with animals or consumers through animal products/food. This highlights the need for more robust guidelines for antibiotic use in intensive farming practices and the necessity of including spp. as an indicator in antibiotic resistance surveillance systems in food animals.
食源性病原体，包括耐药菌，对全球食品安全构成严重威胁，尤其是对食用动物。要确定需要立即采取缓解措施以防止这些细菌进入家庭的关注点，需要全面了解这些病原体在食品生产链中的传播情况。我们采用从农场到餐桌的方法，对南非集约化养猪生产连续过程中的[具体菌属]的分布、抗生素敏感性、分子特征和克隆性进行了调查。使用IDEXX Enterolert/Quanti-Tray 2000系统，从养猪场到餐桌连续过程（农场（猪、运输、屠宰场和零售肉）中获取的452个样本中分离出[具体菌属]。在选择性培养基上获得纯菌落，并通过针对属特异性和种特异性基因的实时PCR进行确认。根据WHO-AGISAR推荐的16种抗生素，按照EUCAST指南，采用 Kirby-Bauer纸片扩散法测定对抗生素的敏感性。通过实时PCR检测选定的抗生素耐药基因和毒力基因。通过REP-PCR评估连续过程中分离株之间的克隆相关性。在农场到餐桌连续过程中，共收集了284株分离株，其中79.2%为[具体菌属1]，6.7%为[具体菌属2]，2.5%为[具体菌属3]，0.4%为[具体菌属4]，11.2%为其他[具体菌属]。分离株对磺胺甲恶唑-甲氧苄啶的耐药性最高（78.8%），对左氧氟沙星的耐药性最低（5.6%）。未观察到对万古霉素、替考拉宁、替加环素和利奈唑胺的耐药性。[具体菌属]对奎奴普丁-达福普汀的耐药率为44.4%。此外，78%的分离株具有多重耐药性。分别有99.1%、96.1%和88.3%的分离株中存在M、[具体基因1]和B基因，证实了对四环素、氨基糖苷类和大环内酯类的表型耐药性。检测到的最常见毒力基因是E。克隆性分析表明，[具体菌属]分离株在连续过程中属于不同的克隆，具有主要的REP类型，主要是来自相同采样来源但不同采样轮次（在农场）的分离株。[具体菌属]分离株显示出较少的多样性。结果表明，集约化养猪可能是耐药菌的储存库，这些耐药菌可通过与动物直接接触或通过动物产品/食品传播给职业暴露工人。这突出了在集约化养殖实践中需要更严格的抗生素使用指南，以及将[具体菌属]纳入食用动物抗生素耐药性监测系统作为指标的必要性。
