Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
J Glob Antimicrob Resist. 2019 Mar;16:210-214. doi: 10.1016/j.jgar.2018.10.015. Epub 2018 Oct 18.
Bacteroides spp. are anaerobic resident intestinal flora but are also known to cause severe morbidity. They are resistant to a wide variety of antimicrobial agents, including metronidazole, which has been shown to be associated with specific nitroimidazole (nim) resistance genes. Metronidazole resistance is emerging worldwide, although presently it remains at ca. 5%. This study aimed to determine the metronidazole susceptibility and distribution of nim genes in Bacteroides spp. clinical isolates in India. The relationship among strains harbouring nim genes and their susceptibility to metronidazole was also analysed.
A total of 42 Bacteroides spp. clinical isolates were identified using an advanced MALDI-TOF system. Minimum inhibitory concentrations (MICs) for metronidazole were determined by the agar dilution method. Bacterial DNA was extracted and was subjected to nim gene PCR and the amplified PCR products were sequenced to determine the prevalent nim types.
Bacteroides fragilis was the most common isolate (64%) among all Bacteroides spp. isolates. Among the total 42 clinical Bacteroides spp. isolates, 29 (69%) were susceptible and 13 (31%) were resistant to metronidazole by the agar dilution method. nim gene PCR performed on 38 isolates showed positivity in 20 isolates (53%), of which 12 had high metronidazole MICs (χ test, P<0.005). On sequencing, these nim genes were most closely related to nimE type.
Resistance to metronidazole is consistently emerging worldwide. There is a significant association of the nim gene with metronidazole resistance. Periodic surveillance is needed to detect geographic and temporal trends in nim gene prevalence.
拟杆菌属是厌氧常驻肠道菌群，但也已知会引起严重的发病率。它们对多种抗菌药物具有耐药性，包括甲硝唑，甲硝唑已被证明与特定的硝基咪唑（nim）耐药基因有关。甲硝唑耐药性在全球范围内不断出现，尽管目前仍约为 5%。本研究旨在确定印度临床分离的拟杆菌属对甲硝唑的敏感性和 nim 基因的分布。还分析了携带 nim 基因的菌株之间的关系及其对甲硝唑的敏感性。
使用先进的 MALDI-TOF 系统鉴定了 42 株拟杆菌属临床分离株。通过琼脂稀释法测定甲硝唑的最小抑菌浓度（MIC）。提取细菌 DNA，并进行 nim 基因 PCR，扩增的 PCR 产物测序以确定流行的 nim 类型。
脆弱拟杆菌是所有拟杆菌属分离株中最常见的分离株（64%）。在总共 42 株临床拟杆菌属分离株中，29 株（69%）对琼脂稀释法的甲硝唑敏感，13 株（31%）耐药。对 38 株进行 nim 基因 PCR 检测，20 株（53%）呈阳性，其中 12 株甲硝唑 MIC 值较高（χ检验，P<0.005）。测序结果显示，这些 nim 基因与 nimE 型最为密切相关。
甲硝唑耐药性在全球范围内不断出现。nim 基因与甲硝唑耐药性有显著相关性。需要定期监测以检测 nim 基因流行率的地理和时间趋势。
