Irrgang Alexandra, Falgenhauer Linda, Fischer Jennie, Ghosh Hiren, Guiral Elisabet, Guerra Beatriz, Schmoger Silvia, Imirzalioglu Can, Chakraborty Trinad, Hammerl Jens A, Käsbohrer Annemarie
Department Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany.
Institute of Medical Microbiology, German Center for Infection Research, Partner Site Giessen-Marburg-Langen, Justus Liebig University, Giessen, Germany.
Front Microbiol. 2017 Nov 21;8:2318. doi: 10.3389/fmicb.2017.02318. eCollection 2017.
Extended-spectrum beta-lactamases (ESBL) mediating resistance to 3rd generation cephalosporins are a major public health issue. As food may be a vehicle in the spread of ESLB-producing bacteria, a study on the occurrence of cephalosporin-resistantu in food was initiated. A total of 404 ESBL-producing isolates were obtained from animal-derived food samples (e.g., poultry products, pork, beef and raw milk) between 2011 and 2013. As CTX-M-15 is the most abundant enzyme in ESBL-producing causing human infections, this study focusses on isolates from food samples harboring the gene. The gene was detected in 5.2% ( = 21) of all isolates. Molecular analyses revealed a phylogenetic group A ST167 clone that was repeatedly isolated from raw milk and beef samples over a period of 6 months. The analyses indicate that spread of CTX-M-15-producing in German food samples were associated with a multireplicon IncF (FIA FIB FII) plasmid and additional antimicrobial resistance genes such as , , different -variants as well as a class 1 integron with an gene cassette. In addition, four phylogenetic group A ST410 isolates were detected. Three of them carried a chromosomal copy of the gene and a single isolate with the gene on a 90 kb IncF plasmid. The gene was always associated with the IS element. In conclusion, CTX-M-15-producing were detected in German food samples. Among isolates of different matrices, two prominent clonal lineages, namely A-ST167 and A-ST410, were identified. These lineages may be important for the foodborne dissemination of CTX-M-15-producing in Germany. Interestingly, these clonal lineages were reported to be widely distributed and especially prevalent in isolates from humans and livestock. Transmission of CTX-M-15-harboring isolates from food-producing animals to food appears probable, as isolates obtained from livestock and food samples within the same time period exhibit comparable characteristics as compared to isolates detected from human. However, the routes and direction of transmission need further investigation.
介导对第三代头孢菌素耐药的超广谱β-内酰胺酶（ESBL）是一个重大的公共卫生问题。由于食物可能是产ESLB细菌传播的载体，因此启动了一项关于食品中头孢菌素耐药性发生情况的研究。2011年至2013年期间，共从动物源性食品样本（如家禽产品、猪肉、牛肉和生牛奶）中获得了404株产ESBL分离株。由于CTX-M-15是导致人类感染的产ESBL中最常见的酶，本研究聚焦于食品样本中携带该基因的分离株。在所有分离株中有5.2%（n = 21）检测到该基因。分子分析揭示了一个A系统发育群ST167克隆，在6个月的时间里从生牛奶和牛肉样本中反复分离得到。分析表明，德国食品样本中产CTX-M-15的细菌传播与一个多复制子IncF（FIA、FIB、FII）质粒以及其他抗菌耐药基因如tet(A)、tet(M)、不同的blaTEM变体以及一个带有aadA基因盒的1类整合子有关。此外，还检测到4株A系统发育群ST410分离株。其中3株携带blaCTX-M-15基因的染色体拷贝，1株携带该基因的90 kb IncF质粒。blaCTX-M-15基因总是与IS元件相关联。总之，在德国食品样本中检测到了产CTX-M-15的细菌。在不同基质的分离株中，鉴定出了两个突出的克隆谱系，即A-ST167和A-ST410。这些谱系可能对德国产CTX-M-15细菌的食源性传播具有重要意义。有趣的是，据报道这些克隆谱系分布广泛，尤其在人和牲畜的分离株中普遍存在。由于在同一时期从牲畜和食品样本中获得的分离株与从人类中检测到的分离株具有可比的特征，因此携带CTX-M-15的分离株从食用动物传播到食物中似乎是可能的。然而，传播途径和方向需要进一步研究。
