临床分离阴沟肠杆菌产超广谱β-内酰胺酶及其基因分析  

Extended-spectrum β-Iactamase produced by E. cloacae clinical isolates and its genotype analysis

作　　者：胡大春[1] 邵剑春[1] 赵晓丽[1] 周玲[1] 刘德华[1] 蒋杰[1] 钱净[1] 杨绍敏[1] 秦海燕[1] 

机构地区：[1]云南省昆明市第一人民医院临床分子生物学重点实验室,650011

出　　处：《国际检验医学杂志》2007年第10期883-887,共5页International Journal of Laboratory Medicine

摘　　要：目的探讨临床分离阴沟肠杆菌对β内酰胺类抗生素的耐药性及其机制。方法采用κ—B法药敏试验检测临床分离阴沟肠杆菌耐药表型；双纸片确认试验和增效试验检测超广谱β-内酰胺酶（ESBLs）或／和高产AmpC酶菌株；PCR方法检测TEM-1、SHV-1、CTX—M型ESBLs编码基因，PCR产物直接测序分析其基因亚型。结果（1）被检菌株对IPM、AK、FEP、CIP耐药率分别是0．0％、14.1％、31.5％、48.4％；对其他常用β-内酰胺类抗生素、CN、SXT等耐药率在50.0％～90.0％以上；（2）88．1％菌株高产AmpC酶或／和产ESBLs；高产AmpC酶、单产ESBLs、同时产AmpC酶和ESBLs的菌株检出率分别为27.38％、16.67％、44.05％。60.70％菌株产ESBLs。（3）TEM-1、SHV-1、CTX-M1组ESBLs编码基因检出率分别为75.00％、23.44％、77.27％。（4）基因序列分析显示存在SHV-12、CTX-M 3.9a、14、22等ESBLs编码基因，以SHV-12、CTX—M14、22为主。结论临床分离阴沟肠杆菌多重耐药严重，对β内酰胺类抗生素的耐药机制复杂，ESBLs编码基因亚型以SHV-12、CTX—M14、22为主。Objective To investigate the drug resistance of Enterobacter cloacae （E. cloacae） clinical isolates to β-1actam antibiotics and its mechanism. Methods The resistance-phenotypes of E. cloacace strains isolated from our hospital from July 2%2 to June 2%4 were determined by Kirby-Bauer disc agar diffusion method according to the Clinical Laboratory Standards Institute （CLSI）. The i- solates producing extended-spectrum β-1actamases （ESBLs） and AmpC beta-lactamases were determined by double disc diffusion confirming test recommended by the CLSI and double disc synergy test. The ESBLs coding genes of blaTEM-1, blaSHV-1 and blaCTX-M were detected by PCR, and the genotypes of blaTEM-1, blaSHV-1 and blaCTX-M were determined by direct sequencing of PCR products. Results （1） The percentage of detected strains resistance to imipenem, amikacin, cefepime and ciprofloxacin was 0.0%, 14.1%, 31.5% and 48.4% respectively, to other commonly used β-1actam antibiotics, gentamicin and trimethoprin/sulfamethoxozol was between 50.0%-90.0%. （2） 88.1% of the isolates highly produced AmpC or/and ESBLs. The percentage of AmpC constitutive highly producing-strains, ESBLs-producing ones and both AmpC- and ESBLs- producing ones was 27. 38%, 16. 67% and 44. 05% respectively. 60. 7% of the strains produced ESBLs. （3） The detection rate of ESBLs coding genes of blaTEM-1, blaSHV-1 and blaCTX-M-1 was 75.%%, 23. 44% and 77. 27% respectively. （4） Gene sequencing revealed there were such ESBLs coding genes as SHV-12, CTX-M- 3, -9a, -14, -22 and so on, and SHV-12, CTX-M-14, and CTX-M-22 were predominant. Conclusion The multi-antibiotics resistance is critical among the E. cloacae clinical isolates in our hospital. The mechanism of resistance to β-1actam antibiotic is complicated. The predominant genotypes of ESBLs in our hospital are different from those of other hospitals in China.

关 键 词：阴沟肠杆菌 耐药性 AMPC酶 ESBLS 基因 

分 类 号：R446.5[医药卫生—诊断学]