肺炎克雷伯菌物种复合体(KpSC)是多药耐药性人类感染的主要原因。为了更好地理解食物作为KpSC载体的潜在贡献,我们进行了一项多中心研究,以确定从食物基质中回收食物的最佳培养方法,并对食物分离物进行表型和基因型表征。在五个欧洲国家收集鸡肉(n=160)和沙拉(n=145)样品,并使用基于培养物和zur-khe基因间区域(ZKIR)定量PCR(qPCR)方法筛选KpSC的存在。使用缓冲蛋白胨水进行富集,然后在西蒙斯柠檬酸盐琼脂上用肌醇划线(44°C持续48小时)被定义为最适合KpSC回收的选择性培养方法。在鸡肉中发现KpSC的高患病率(通过ZKIRqPCR和培养方法分别为60%和52%,分别)和沙拉(30%和21%,分别)样本。基因组分析显示,具有系统群Kp1(91%)和Kp3(6%)的优势的遗传多样性很高。总共82%的分离株呈现天然的抗微生物药敏表型和基因型,仅检测到四个产生CTX-M-15的分离株。值得注意的是,在样本中发现了相同的基因型-相同的食物类型和相同的国家(15例),不同的食物类型和相同的国家(1),和相同的食物类型和两个国家(1)-表明KpSC在粮食部门的传播率高。我们的研究提供了从食物基质中分离KpSC的新策略,并加强了食物作为人类KpSC定植的潜在来源的观点。重要性肺炎克雷伯菌物种复合体(KpSC)的细菌无处不在,肺炎克雷伯菌是人类抗生素耐药性感染的主要原因。尽管肺炎克雷伯菌面临着紧迫的公共卫生威胁,对食物来源对人类定殖和随后感染的贡献缺乏了解。这部分是由于缺乏用于表征食物基质中KpSC存在的标准化方法。我们的多中心研究提供并实现了从食物基质中分离KpSC的新策略,并表明KpSC成员在沙拉和鸡肉中非常普遍。强化了食物作为人类KpSC定殖的潜在来源的观点。尽管遗传多样性很大,检测到的抗性水平很低,样本中相同基因型的出现表明KpSC在食品行业中的传播率很高,需要进一步探索以定义可能的控制策略。
The Klebsiella pneumoniae species complex (KpSC) is a leading cause of multidrug-resistant human infections. To better understand the potential contribution of food as a vehicle of KpSC, we conducted a multicentric
study to define an optimal culture method for its recovery from food matrices and to characterize food isolates phenotypically and genotypically. Chicken meat (n = 160) and salad (n = 145) samples were collected in five European countries and screened for the presence of KpSC using culture-based and zur-khe intergenic region (ZKIR) quantitative PCR (qPCR) methods. Enrichment using buffered peptone water followed by streaking on Simmons citrate agar with inositol (44°C for 48 h) was defined as the most suitable selective culture method for KpSC recovery. A high prevalence of KpSC was found in chicken meat (60% and 52% by ZKIR qPCR and the culture approach, respectively) and salad (30% and 21%, respectively) samples. Genomic analyses revealed high genetic diversity with the dominance of phylogroups Kp1 (91%) and Kp3 (6%). A total of 82% of isolates presented a natural antimicrobial susceptibility phenotype and genotype, with only four CTX-M-15-producing isolates detected. Notably, identical genotypes were found across samples-same food type and same country (15 cases), different food types and same country (1), and same food type and two countries (1)-suggesting high rates of transmission of KpSC within the food sector. Our
study provides a novel isolation strategy for KpSC from food matrices and reinforces the view of food as a potential source of KpSC colonization in humans. IMPORTANCE Bacteria of the Klebsiella pneumoniae species complex (KpSC) are ubiquitous, and K. pneumoniae is a leading cause of antibiotic-resistant infections in humans. Despite the urgent public health threat represented by K. pneumoniae, there is a lack of knowledge of the contribution of food sources to colonization and subsequent infection in humans. This is partly due to the absence of standardized methods for characterizing the presence of KpSC in food matrices. Our multicentric
study provides and implements a novel isolation strategy for KpSC from food matrices and shows that KpSC members are highly prevalent in salads and chicken meat, reinforcing the view of food as a potential source of KpSC colonization in humans. Despite the large genetic diversity and the low levels of resistance detected, the occurrence of identical genotypes across samples suggests high rates of transmission of KpSC within the food sector, which need to be further explored to define possible control strategies.