水环境中耐热大肠菌群的抗生素耐药性与质粒谱研究

用滤膜法、mFC培养基从5种水体中分离出疑似耐热大肠菌162株,用API微生物分析系统鉴定到种,以Kirby-Bauer法分析其对人畜常用10种抗生素的耐药性,碱裂解法小量制备各菌株质粒DNA做质粒谱分析.结果表明,埃希氏大肠杆菌为优势菌,占分离菌总数的96.3%.除分离自泉水的3株外,其它菌株都对3种及3种以上抗生素耐药,多重耐药率为98.1%.不同水体分离菌株对氧氟沙星、诺氟沙星、庆大霉素、丁胺卡那霉素、链霉素的耐药率有显著性差异(P<0.005).92株菌(56.8%)提取到大小为0.90～158.83kb、数量为1～6个的质粒,有81种质粒谱型.70株(43.2%)未提取到质粒的细菌中有67株为多重耐药.具有相同质粒谱型的菌株耐药谱都不相同.未发现质粒谱与抗生素耐药性间有明显相关性.图1表3参15

Antibiotic Resistance and Plasmid Profile of Thermotolerant Coliform Bacteria Isolated from Aquatic Environment

A total of 162 strains were isolated by membrane filter method and m-FC agar from aquatic environment, and identified by API system. The resistance to 10 kinds of most frequently used antibiotics in human and animals was analyzed by Kirby-Bauer method. The results showed that E. coli (96.3%) was the predominant strains of the all isolates. All isolates were resistant to three or more antibiotics except three strains isolated from spring, and the incidence of multiple antibiotic resistance (MAR) was 98.1%. The resistance rates to ofloxacin, norfloxacin, gentamicin, amikacin and streptomycin of the isolates from different types of water bodies were significantly different (P<0.005). Plasmids of 92 isolates (56.8%) with the size of 0.90~158.83 kb and quantity of 1~6 were isolated, and 81 kinds of plasmid profiles were found. The isolates free of plasmids were resistant to two or more antibiotics. The isolates that had the same plasmid profiles were all different in resistance patterns. There was no relativity between the plasmid profiles and resistance pattern. Fig 1, Tab 3, Ref 15