一株洛菲不动杆菌对碳青霉烯类抗生素耐药机制的研究

目的研究洛菲不动杆菌对亚胺培南、美洛培南耐药的分子机制。方法K-B纸片琼脂扩散法检测洛菲不动杆菌B69对头孢他啶、头孢曲松、环丙沙星、阿米卡星的耐药性,琼脂对倍稀释法检测B69对亚胺培南、美洛培南的最低抑菌浓度;PCR扩增OXA、IMP、VIM型碳青霉烯酶基因,测序确定耐药基因型别;粗提酶水解亚胺培南纸片试验检测酶活性。结果洛菲不动杆菌B69具有多重耐药性;PCR扩增IMP基因阳性,经测序为IMP-8;粗提酶水解亚胺培南。结论产IMP-8型金属β-内酰胺酶是洛菲不动杆菌B69对碳青霉烯耐药的重要机制。

Mechanism of carbapenem resistance in an Acinetobacter lwoffii

Objective To investigate the mechanism of carbapenem resistance in an Acinetobacter lwoffii. Methods K-B disk diffusion method was used for susceptibility test of the antimicrobial agents of ceftazidime, cefiriaxone, ciprofloxacin and amikacin against Acinetobacter lwoffii named B69. The susceptibility tests of imipenem and meropenem were carried out by means of the agar dilution. PCR technique was applied to dectect the genes encoding OXA, IMP and VIM-type car-bapenemases. The genes which were dectected through sequenced. Crude enzemy extract of B69 was applied to hydrolysis imipenem. Results The isolate showed resistance to all the tested antimicrobial agents except for ciprofloxacin. PCR and DNA sequencing results showed the isolate harbors IMP-8 gene. Crude enzemy extract of the isolate could hydrolysis imipenem. Conclusion Producing IMP-8 metalloenzyme could be the major cause for the carbapenem resistance in the Acineto- bacter lwoffii B69.