产β-内酰胺酶鲍曼不动杆菌基因型研究

目的了解临床科室分离的鲍曼不动杆菌耐药状况并分析多重耐药株产β-内酰胺酶基因型,为有效的临床治疗和医院感染控制提供实验室依据。方法采用纸片扩散（K-B）法测定临床分离的312株鲍曼不动杆菌对13种抗菌药物的敏感性,对其中120株多重耐药株用聚合酶链反应（PCR）扩增β-内酰胺酶基因,并对其扩增产物进行基因测序。结果鲍曼不动杆菌对美洛培南、亚胺培南、头孢哌酮/舒巴坦和替卡西林/克拉维酸的耐药率分别为0.0%、1.0%、30.8%和31.4%,其余抗菌药物耐药率在38.5%-80.1%;120株多重耐药菌株中,β-内酰胺酶基因分布AmpC型基因阳性率为66.7%（80/120）、SHV-12型基因阳性率为14.2%（17/120）,PER-1型基因阳性率为16.7%（20/120）,CTX-M-9型基因阳性率为8.2%（10/120）,TEM-1型基因阳性率为9.2%（11/120）;VER-1,CTX-M-1,CTX-M-2,OXA型均阴性。同时携带2种基因型有16株,携带3种基因型有14株。结论临床分离的鲍曼不动杆菌流行株主要是产AmpC酶,且呈多重耐药。

Study on genotypes of β-Lactamases producing Acinetobacter baumannii

Objective To explore the antimicrobial resistance of Acinetobacter baumannii and the genotype of multidrug-resistant β-Lactamase producing Acinetobacter baumannii isolated from clinical specimens in order to provide the laboratory information for effective control and treatment of the infectious diseases.Method Kirby-Bauer (K-B) tests were performed to detect the susceptibility of 312 strains of Acinetobacter baumannii to 13 kinds of antimicrobial agents. The genotypes of β-Lactamase producing gene in multidrug-resistant Acometobacter baumannii were detected by multiple PCR amplification and then the DNA products were sequenced. Result The resistance rates of the 312 Acinetobacter baumannii isolates to Imipenam, Cefoperazone/sulbactam and Ticarcillin/clavulanic were 1.0%, 30.8% and 31.4%, respectively. The resistance rates to other antimicrobial agents were between 38.5%～80.1%. The positive rates of AmpC, SHV-12, PER-1, CTX-M-9 and TEM-1 among β-Lactamase genes in 120 multidrug-resistant strains were 66.7% (80/120), 14.2% (17/120), 16.7% (20/120), 8.2% (10/120) and 9.2% (11/120), respectively. VER-1, CTX-M-1, CTX-M-2 and OXA genes were not found. There were two different genes in 16 strains, and three different genes in 14 strains.Conclusion Strains that produce AmpC were predominant among Acinetobacter baumannii isolated from clinical specimens and were also multiresistant.