Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and Medical School, University of Szeged, Szeged, Hungary.
Department of Microbiology and Infection Control, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
BMC Microbiol. 2024 Jun 8;24(1):202. doi: 10.1186/s12866-024-03354-w.
Bacteroides fragilis group (BFG) species are the most significant anaerobic pathogens and are also the most antibiotic-resistant anaerobic species. Therefore, surveying their antimicrobial resistance levels and investigating their antibiotic resistance mechanisms is recommended. Since their infections are endogenous and they are important constituents of the intestinal microbiota, the properties of the intestinal strains are also important to follow. The aim of this study was to investigate the main antibiotic gene content of microbiota isolates from healthy people and compare them with the gene carriage of strains isolated from infections.
We detected 13, mainly antibiotic resistance determinants of 184 intestinal BFG strains that were isolated in 5 European countries (Belgium, Germany, Hungary, Slovenia and Turkey) and compared these with values obtained earlier for European clinical strains. Differences were found between the values of this study and an earlier one for antibiotic resistance genes that are considered to be mobile, with higher degrees for cfxA, erm(F) and tet(Q) and with lower degrees for msrSA, erm(B) and erm(G). In addition, a different gene prevalence was found depending on the taxonomical groups, e.g., B. fragilis and NBFB. Some strains with both the cepA and cfiA β-lactamase genes were also detected, which is thought to be exceptional since until now, the B. fragilis genetic divisions were defined by the mutual exclusion of these two genes.
Our study detected the prevalences of a series of antibiotic resistance genes in intestinal Bacteroides strains which is a novelty. In addition, based on the current and some previous data we hypothesized that prevalence of some antibiotic resistance genes detected in the clinical and intestinal BFG strains were different, which could be accounted with the differential composition of the Bacteroides microbiota and/or the MGE mobilities at the luminal vs. mucosal sites of the intestine.
脆弱拟杆菌群（BFG）物种是最重要的厌氧病原体，也是最具抗药性的厌氧物种。因此，建议调查它们的抗药性水平，并研究它们的抗生素耐药机制。由于它们的感染是内源性的，并且它们是肠道微生物群的重要组成部分，因此肠道菌株的特性也很重要。本研究的目的是调查来自健康人群的微生物群分离株的主要抗生素基因含量，并将其与从感染中分离的菌株的基因携带情况进行比较。
我们检测到了 13 种主要的抗生素抗性决定因子，这些因子存在于 5 个欧洲国家（比利时、德国、匈牙利、斯洛文尼亚和土耳其）的 184 株肠道 BFG 菌株中，并将这些数据与之前获得的欧洲临床菌株数据进行了比较。在被认为是可移动的抗生素抗性基因方面，本研究的结果与早期研究结果存在差异，其中 cfxA、erm(F) 和 tet(Q) 的程度较高，msrSA、erm(B) 和 erm(G) 的程度较低。此外，还发现了不同的基因流行率，这取决于分类群，例如脆弱拟杆菌和 NBFB。还检测到了一些同时携带 cepA 和 cfiA β-内酰胺酶基因的菌株，这被认为是异常的，因为到目前为止，B. fragilis 的遗传分类是通过这两个基因的相互排斥来定义的。
我们的研究检测到了肠道拟杆菌菌株中一系列抗生素抗性基因的流行率，这是一个新发现。此外，根据目前和一些以前的数据，我们假设在临床和肠道 BFG 菌株中检测到的一些抗生素抗性基因的流行率不同，这可能与肠道拟杆菌菌群的差异组成和/或 MGE 在肠腔表面的可移动性有关。
