多重耐药鲍曼不动杆菌表型及耐药基因型的研究

Study on phenotype and genotype of multiresistant Acinetobacter baumannii

目的对我院临床分离的31株多重耐药鲍曼不动杆菌表型和耐药基因进行分析。方法用纸片扩散法检测鲍曼不动杆菌的药敏结果,用三维试验检测超广谱β-内酰胺酶(ESBL)、头孢菌素酶(AmpC酶),用协同法检测金属β-内酰胺酶(MBL),用聚合酶链反应(PCR)检测耐药基因。结果31株多重耐药鲍曼不动杆菌中,90%对亚胺培南敏感;22%对头孢哌酮-舒巴坦耐药,74%中介;其他抗菌药物的敏感率均在6%以下。2株菌(6%)单产ESBL;93%菌株高产AmpC酶,其中19%菌株同时产ESBL。所有菌株b laTEM、aacA4和gyrA基因均为阳性;96%菌株ampC基因为阳性;2株菌同时携带b laPER和b laOXA-23型基因,另有1株菌b laOXA-23基因阳性。结论同时携带b laTEM、ampC、aacA4和gyrA突变以及b laPER、b laOXA-23等多种耐药基因是鲍曼不动杆菌多重耐药的主要原因。

Objective To analyse the resistant genotype and phenotype of 31 strains of multiresistant Acinetobacter baumannii in clinical isolation from our hospital. Methods Antibiotic susceptibility tests were performed by K-B methods, three dimensional extract tests were performed to detect extended spectrum β-lactamase （ESBL）-producing strains and cephalosporinase （AmpC）-producing strains, metallo-β-lactamases （MBL）-producing strains were detected by synergetic tests, and the resistant genes were amplified by polymerase chain reaction （PCR）. Results In 31 strains ofmuhiresistant Acinetobacter baumannii, 90% were susceptible to imipenem; 22% were resistant to cefoperazone/sulbactam and 74% were intermediate; other antibiotic susceptibility was not over 6% ; 2 strains produced ESBL; 93% strains produced AmpC and 19% strains produced ESBL at the same time. blaTEM, aacA4 and gyrA genes were positive in all strains; ampC genes in 96% strains were positive; blapER and blaoxs_23 genes were both positive in 2 strains, another strain carried blaOXA-23 genes. Conclusions Carring several resistant genes including blaTEM , and ampC, aacA4, mutation of gyrA and blaFER et al mav be main reason that causes Acinetobacter baumannii multidrug resistant.