连续5年鲍氏不动杆菌主动外排基因分布变迁及耐药性研究

Change of distribution of 21 efflux pump genes in Acinetobacter baumannii and analysis of drug resistance in 5 consecutive years

目的了解5年鲍氏不动杆菌(ABA)主动外排基因分布变迁及耐药性,为抗菌药物合理应用提供依据。方法收集2005年2月-2009年12月住院患者送检标本分离出的162株ABA,采用K-B法进行抗菌药物敏感试验,多重PCR-反向线点杂交技术检测21个主动外排基因。结果 162株ABA中多药耐药菌(MDR)占80.9%,除cmlA5外,其余20个外排泵基因均有阳性携带株;外排系统在MDR及相对敏感菌株中均有分布,部分外排泵基因在MDR中的分布明显高于相对敏感株(P<0.05);外排泵基因MATE36_127、ABC2_694、adeA、adeB、adeC、adeR、adeS及qacEdelta1在MDR中阳性率呈逐年上升趋势(P<0.05);一株菌同时携带多个外排泵家族,优势外排基因各年度情况不尽相同。结论临床分离的ABA耐药情况严峻,主动外排基因分布广泛,外排泵基因型的变化与耐药表型之间可能存在一定关系。

OBJECTIVE To explore the change of distribution of 21 efflux pump genes in Acinetobacter baumannii and analyze the drug resistance in 5 consecutive years so as to provide basis for the reasonable clinical use of antibiotics. METHODS A total of 162 strains of A. baurnannii were isolated from the submitted specimens obtained from the patients who were hospitalized from Feb 2005 to Dec 2009, then the drug susceptibility testing was performed with the use of K-B method, and 21 efflux pump genes were detected by using multiplex PCR-reverse line blot hybridization technique. RESULTS Of totally 162 strains of A. baumannii isolated, the multidrug- resistant （MDR） strains accounted for 80. 9~; the A. baurnannii strains carried all the 21 efflux pump genes except for crnlA5. The efflux pump systems were discovered not only in the MDR isolates but also in sensitive isolates. For some of the efflux pump genes, the MDR strains carrying those genes were significantly more than the sensitive strains（P〈0.05）; the positive rates of the efflux pump genes in the MDR strains, including MATE 36127, ABC 2_694, adeA, adeB, adeC, adeR, adeS, and qacEdeltal, showed an upward trend （P〈0.05）. There was one strain carrying multiple efflux pump gene family at the same time, and the distribution of the dominant genes varied in the five consecutive years. CONCLUSION The clinical isolates of A. baumannii are highly drug resistant. The efflux pump genes are widely distributed; the study concludes that the drug resistance phenotype may be related to the change of the efflux pump genes.