脆弱拟杆菌耐药性及对克林霉素耐药基因的检测

An analysis of resistance to 18 antibiotics in Bacteroides fragilis and a study on resistant gene to clindamycin

目的了解脆弱拟杆菌对临床常用抗生素的耐药性，并对克林霉素耐药基因进行检测。方法采用琼脂稀释法测定７９株脆弱拟杆菌对１８种抗生素的耐药性，通过聚合酶链反应检测克林霉素的耐药基因。结果７９株脆弱拟杆菌对１８种抗生素中的１０种耐药率＞５０％，对克林霉素、甲硝唑的耐药率最低，分别为７５９％和８８６％。筛选出６株对克林霉素高度耐药株（最小抑菌浓度≥５１２ｍｇ／Ｌ），进行质粒ＤＮＡ检测均未测到质粒。从６株高耐药株中均扩增出克林霉素耐药基因片段（ｅｒｍＦ中的一段）。结论克林霉素、甲硝唑对脆弱拟杆菌的抗菌活性最强。

Objective To find the resistance to commonly used antibiotics and the clindamycin resistant gene of Bacteroides fragilis (B. fragilis). Methods The minimal inhibitory concertration (MIC) of 18 antibiotics was determined by agarose gel dilution in 79 clinical strains of Bacteroides and polymerase chain reaction (PCR) was used to assay the clindamycin resistant gene. Results The strains B. fragilis were most susceptible to clindamycin (MIC 90 4 mg/L) and metronidazole (MIC 90 8 mg/L). Six strains highly resistant to clindamycin were screened from the 79 clinical strains (MIC≥512 mg/L), none of six strains contained any detectable plasmids. Clindamycin resistant gene was detected from the six highly resistant strains depending upon the template of chromosome DNA. Conclusion This element represents a mechanism of chromosome genetic mediator of clindamycin resistance in B. fragilis.