Each laboratory collected 20-25 Bacteroides (including Phocaeicola and Parabacteroides) and 10-15 Prevotella isolates for 3 months. At the national reference laboratory, the MICs of amoxicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam, meropenem, imipenem, metronidazole, clindamycin, tetracycline and moxifloxacin were determined using agar dilution. Isolates with a high MIC of metronidazole or a carbapenem, or harbouring cfiA, were subjected to WGS.
Bacteroides thetaiotaomicron/faecis isolates had the highest MIC90 values, whereas Bacteroides fragilis had the lowest MIC90 values for amoxicillin/clavulanic acid, piperacillin/tazobactam, meropenem, imipenem and moxifloxacin. The antimicrobial profiles of the different Prevotella species were similar, except for amoxicillin, for which the MIC50 ranged from 0.125 to 16 mg/L for Prevotella bivia and Prevotella buccae, respectively. Three isolates with high metronidazole MICs were sequenced, of which one Bacteroides thetaiotaomicron isolate harboured a plasmid-located nimE gene and a Prevotella melaninogenica isolate harboured a nimA gene chromosomally.Five Bacteroides isolates harboured a cfiA gene and three had an IS element upstream, resulting in high MICs of carbapenems. The other two isolates harboured no IS element upstream of the cfiA gene and had low MICs of carbapenems.
Variations in resistance between species were observed. To combat emerging resistance in anaerobes, monitoring resistance and conducting surveillance are essential.
方法:每个实验室收集了20-25个拟杆菌(包括Phocaeicola和Parabteroides)和10-15个Prevotella分离株,为期3个月。在国家参考实验室,阿莫西林的MIC,阿莫西林/克拉维酸,哌拉西林/他唑巴坦,美罗培南,亚胺培南,甲硝唑,克林霉素,四环素和莫西沙星用琼脂稀释液测定。具有高MIC的甲硝唑或碳青霉烯的分离物,或者窝藏CFIA,受到WGS的约束。
结果:拟杆菌的MIC90值最高,而脆弱拟杆菌对阿莫西林/克拉维酸的MIC90值最低,哌拉西林/他唑巴坦,美罗培南,亚胺培南和莫西沙星.不同Prevotella物种的抗菌谱相似,除了阿莫西林,Bivia和Bepervotella的MIC50范围为0.125至16mg/L,分别。对三个具有高甲硝唑MIC的分离株进行了测序,其中一种拟杆菌属细菌分离株具有质粒定位的nimE基因,而一种黑色素Prevotella分离株具有染色体上的nimA基因。五个拟杆菌分离株含有cfiA基因,三个在上游有IS元件,导致碳青霉烯类的MIC高。另外两个分离株在cfiA基因上游没有IS元件,碳青霉烯类的MIC较低。
结论:观察到物种之间的抗性变化。为了对抗厌氧菌中出现的抗药性,监测阻力和进行监测是必不可少的。