脆弱拟杆菌群环境分离株中出现的抗微生物药物耐药性。
The emergence of antimicrobial resistance in environmental strains of the Bacteroides fragilis group.
机构信息
Department of Environmental Microbiology, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-957 Olsztyn, Poland.
Department of Microbiology, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Mexico City, Mexico.
出版信息
Environ Int. 2019 Mar;124:408-419. doi: 10.1016/j.envint.2018.12.056. Epub 2019 Jan 22.
Anaerobic bacteria of the genus Bacteroides are a large group of commensal microorganisms that colonize the human and animal digestive tract. The genus Bacteroides and the closely related genus Parabacteroides include the Bacteroides fragilis group (BFG) of potentially pathogenic bacteria which are frequently isolated from patients with anaerobic infections. The aim of this study was to assess the antimicrobial resistance of environmental strains of the Bacteroides fragilis group. Strains were isolated from human feces, hospital wastewater, influent (UWW) and effluent (TWW) wastewater from a wastewater treatment plant (WWTP), and from the feces of lab rats as a negative control to monitor the entire route of transmission of BFG strains from humans to the environment. The resistance of 123 environmental BFG strains to six antibiotic groups was analyzed with the use of culture-dependent methods. Additionally, the presence of 25 genes encoding antibiotic resistance was determined by PCR. The analyzed environmental BFG strains were highly resistant to the tested antibiotics. The percentage of resistant strains differed between the analyzed antibiotics and was determined at 97.56% for ciprofloxacin, 49.59% for erythromycin, 44.71% for ampicillin, 35.77% for tetracycline, 32.52% for amoxicillin/clavulanic acid, 26.83% for chloramphenicol, 26.01% for clindamycin, 11.38% for moxifloxacin, and 8.94% for metronidazole. The highest drug-resistance levels were observed in the strains isolated from UWW and TWW samples. The mechanisms of antibiotic-resistance were determined in phenotypically resistant strains of BFG. Research has demonstrated the widespread presence of genes encoding resistance to chloramphenicol (100% of all chloramphenicol-resistant strains), tetracyclines (97.78% of all tetracycline-resistant strains), macrolides, lincosamides and streptogramins (81.97% of all erythromycin-resistant strains). Genes encoding resistance to β-lactams and fluoroquinolones were less prevalent. None of the metronidazole-resistant strains harbored the gene encoding resistance to nitroimidazoles. BFG strains isolated from UWW and TWW samples were characterized by the highest diversity of antibiotic-resistance genes and were most often drug-resistant and multidrug-resistant. The present study examines the potential negative consequences of drug-resistant and multidrug-resistant BFG strains that are evacuated with treated wastewater into the environment. The transmission of these bacteria to surface water bodies can pose potential health threats for humans and animals; therefore, the quality of treated wastewater should be strictly monitored.
拟杆菌属的厌氧细菌是一大类共生微生物，定植于人和动物的消化道。拟杆菌属和密切相关的副拟杆菌属包括潜在致病性的脆弱拟杆菌群（BFG），这些细菌常从厌氧感染患者中分离出来。本研究旨在评估环境中脆弱拟杆菌群的抗菌药物耐药性。菌株从人类粪便、医院废水、污水处理厂进水（UWW）和出水（TWW）以及实验室大鼠粪便中分离出来，大鼠粪便作为阴性对照，以监测 BFG 菌株从人类传播到环境的整个途径。使用依赖培养的方法分析了 123 株环境 BFG 对 6 组抗生素的耐药性。此外，通过 PCR 确定了 25 个编码抗生素耐药性的基因。分析的环境 BFG 菌株对测试的抗生素具有高度耐药性。分析的抗生素之间耐药菌株的百分比不同，环丙沙星为 97.56%，红霉素为 49.59%，氨苄西林为 44.71%，四环素为 35.77%，阿莫西林/克拉维酸为 32.52%，氯霉素为 26.83%，克林霉素为 26.01%，莫西沙星为 11.38%，甲硝唑为 8.94%。在从 UWW 和 TWW 样本中分离的菌株中观察到最高的药物耐药水平。在 BFG 的表型耐药菌株中确定了抗生素耐药的机制。研究表明，对氯霉素（所有氯霉素耐药菌株的 100%）、四环素（所有四环素耐药菌株的 97.78%）、大环内酯类、林可酰胺类和糖肽类具有广泛的耐药基因。β-内酰胺类和氟喹诺酮类的耐药基因则较少。没有一株甲硝唑耐药株携带硝基咪唑类耐药基因。从 UWW 和 TWW 样本中分离的 BFG 菌株具有抗生素耐药基因的最高多样性，且通常为耐药和多药耐药。本研究考察了用处理后的废水排放到环境中具有耐药性和多药耐药性的 BFG 菌株可能带来的负面影响。这些细菌传播到地表水可能对人类和动物构成潜在的健康威胁；因此，应严格监测处理后的废水质量。
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