Hansen Kia Cirkeline Møller, Schwensen Simon A F, Henriksen Daniel Pilsgaard, Justesen Ulrik Stenz, Sydenham Thomas Vognbjerg
Department of Clinical Microbiology, OUH Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C, Denmark.
Department of Respiratory Medicine, OUH Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C, Denmark; Department of Clinical Biochemistry and Pharmacology, OUH Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C, Denmark.
Anaerobe. 2017 Oct;47:79-85. doi: 10.1016/j.anaerobe.2017.04.013. Epub 2017 Apr 23.
Members of the Bacteroides fragilis group are opportunistic pathogens and cause severe infections including bacteraemia. As increased levels of antimicrobial resistance in B. fragilis group bacteria can be detected years after administration of specific antibiotics, monitoring antimicrobial susceptibility in the gut microbiota could be important. The objectives of this study were to 1) investigate the distribution of species and the occurrence of reduced antimicrobial susceptibility in the B. fragilis group from patients treated at departments with a high level of antibiotic use, 2) to determine the prevalence of the carbapenem resistance gene cfiA in B. fragilis in this patient group, and 3) to determine the association between previous antibiotic treatment and reduced susceptibility to clindamycin, meropenem, metronidazole, and piperacillin-tazobactam. Consecutive faecal samples (n = 197) were collected from patients at the departments of haematology, oncology, and infectious diseases at Odense University Hospital, Denmark. Three colonies from each sample were identified by Matrix Assisted Lazer Desorption Ionization Time of Flight Mass Spectrometry and isolates were screened for resistance to clindamycin, meropenem, metronidazole, and piperacillin-tazobactam. B. fragilis isolates were tested for the cfiA metallo-beta-lactamase gene. Fisher's Exact test was used to test for correlation between antimicrobial exposure and reduced susceptibility. A total of 359 isolates were tested for reduced susceptibility. Of these 28%, 5%, <1%, and 11% were intermediate susceptible or resistant to clindamycin, meropenem, metronidazole, and piperacillin-tazobactam respectively. Three metronidazole resistant Bacteroides spp. were isolated. The proportion of B. fragilis belonging to division II (cfiA+) was 5.3%. Previous exposure to meropenem was associated with reduced susceptibility to meropenem (p= 0.001). In conclusion, antimicrobial resistance is prevalent and the distribution of species appears to be affected in the B. fragilis group from patients receiving broad-spectrum antibiotics, with meropenem exposure being associated with meropenem resistance.
脆弱拟杆菌群的成员是机会致病菌，可引起包括菌血症在内的严重感染。由于在使用特定抗生素数年之后，仍可检测到脆弱拟杆菌群细菌的耐药性水平升高，因此监测肠道微生物群中的抗菌药物敏感性可能很重要。本研究的目的是：1）调查在抗生素使用水平较高的科室接受治疗的患者中，脆弱拟杆菌群的菌种分布及抗菌药物敏感性降低的情况；2）确定该患者群体中脆弱拟杆菌对碳青霉烯耐药基因cfiA的携带率；3）确定既往抗生素治疗与对克林霉素、美罗培南、甲硝唑和哌拉西林-他唑巴坦敏感性降低之间的关联。从丹麦欧登塞大学医院血液科、肿瘤科和传染病科的患者中连续采集粪便样本（n = 197）。通过基质辅助激光解吸电离飞行时间质谱法对每个样本中的三个菌落进行鉴定，并对分离株进行克林霉素、美罗培南、甲硝唑和哌拉西林-他唑巴坦耐药性筛查。对脆弱拟杆菌分离株检测cfiA金属β-内酰胺酶基因。采用Fisher精确检验来检测抗菌药物暴露与敏感性降低之间的相关性。共检测了359株分离株的敏感性降低情况。其中，分别有28%、5%、<1%和11%对克林霉素、美罗培南、甲硝唑和哌拉西林-他唑巴坦呈中介敏感或耐药。分离出3株耐甲硝唑的拟杆菌属菌株。属于第二组（cfiA+）的脆弱拟杆菌比例为5.3%。既往使用美罗培南与对美罗培南敏感性降低相关（p = 0.001）。总之，在接受广谱抗生素治疗的患者中，脆弱拟杆菌群中普遍存在抗菌药物耐药性，且菌种分布似乎受到影响，美罗培南暴露与美罗培南耐药相关。
