某院肺炎克雷伯菌产质粒AmpC酶基因型及耐药性研究

目的调查该院临床分离肺炎克雷伯菌产质粒AmpC酶表型和基因型携带情况及其对常用抗生素的耐药性,为临床合理用药提供参考。方法采用Vitek2-compact全自动细菌鉴定药敏系统对临床分离菌株进行鉴定及药物敏感试验,采用头孢西丁三维试验检测AmpC酶表型,采用多重PCR方法检测AmpC基因并经DNA测序确定其基因型别。结果 2010年7月至2011年6月共分离到116株肺炎克雷伯菌,产AmpC酶肺炎克雷伯菌占18.1%(21/116)。产AmpC酶肺炎克雷伯菌多重耐药情况严重,对氨基糖甙类、喹诺酮类及大多数头孢菌素类抗菌药物的耐药率在57.1%～100%,对加酶抑制剂复合药氨苄西林/舒巴坦、阿莫西林/克拉维酸、头孢哌酮/舒巴坦及哌拉西林/他唑巴坦的耐药率分别为90.5%、85.7%、42.9%、38.1%,所有菌株对碳青霉烯类抗生素亚安培南和美罗培南仍全部敏感。产AmpC酶菌株对头孢西丁、第3代头孢菌素及氨苄西林/舒巴坦、阿莫西林/克拉维酸等抗生素的耐药率明显高于不产酶株(P<0.05)。21株产酶菌株均携带DHA-1型AmpC酶基因。结论该院肺炎克雷伯菌产AmpC酶株检出率较高,产酶菌株多重耐药情况严重。临床应根据药敏结果合理选用抗菌药物,以减少耐药菌株的产生。

Drug resistance and genotype of plasmid AmpC enzyme in Klebsiella pneumoniae in a hospital of Chongqing

Objective To investigate the prevalence and genotypes of AmpC beta-lactamase produced by Klebsiella pneumoniae in our hospital,and analyze its antibiotic resistance.Methods The identification and antibiotics susceptibility of isolates were determined by the Vitek2-compact automatic microbial identification system.AmpC beta-lactamases was detected by three-dimensional extract test.Genotypes of AmpC beta-lactamases were determined by multiplex PCR and DNA sequencing.Results A total of 116 isolates were collected from Jul 2010 to Jun 2011.The AmpC beta-lactamase were detected in 21 isolates,accounting for 18.1%.The resistants of AmpC beta-lactamases-producing isolates to third-generation cephalosporins,aminoglycosides,and quinolones antibiotics were 57.1%-100%.The resistances to ampicillin/sulbactam,amoxicillin/clavulanate,cefoperazone/sulbactam,and piperacillin/tazobactam were 90.5%,85.7%,42.9%,38.1%,respectively.All isolates were sensitive to imipenem and meropenem.The resistances of AmpC beta-lactamase positive strains to drugs such as cefoxitin,third-generation cephalosporins,ampicillin/sulbactam,amoxicillin/clavulanate were significantly higher than that of AmpC beta-lactamase negative strains.The genotypes of AmpC beta-lactamases in all 21 isolates were DHA-1 type.Conclusion The multiple drug resistance of AmpC producing K.pneumoniae in our hospital was serious and the ratio of AmpC beta-lactamases producing strains was higher.The antibiotic for the treatment of infection caused by AmpC producing K.pneumoniae should be used according to antibiotic susceptibility test results.