阴沟肠杆菌不同β-内酰胺酶基因型检测与耐药性研究

Detection of Different Genotyping of β-Lactamases and Drug Resistance in Enterobater cloacae

摘要：目的了解医院感染阴沟肠杆菌产β-内酰胺酶的情况，并对产不同β-内酰胺酶型菌株的耐药性进行研究。方法采用三维试验确证试验检测AmpC酶与超广谱β-内酰胺酶（ESBLs），聚合酶链反应（PCR）扩增基因，K—B法检测阴沟肠杆菌对13种抗菌药物的耐药情况。结果80株阴沟肠杆菌中29株ESBLs编码基因结果阳性，3株含有两种不同的基因型，分别为TEM型6株、SHV-2型2株、CTX-M-2型5株、CTX-M-3型8株和CTX—M-9型11株；26株ampC基因PCR扩增呈阳性；产超超广谱肛内酰胺酶（SSBLs）阴沟肠杆菌对美罗培南外的12种抗菌药物的耐药率在66．7％～100．0％，无论是单一产酶株，还是SSBLs菌株，其耐药率均显著高于不产酶株，差异有统计学意义（P〈0．05）；美罗培南仍是阴沟肠杆菌耐药率最低的抗菌药物。结论阴沟肠杆菌已呈现出多药耐药和高度耐药特征，ESBLs基因型以CTX—M型为主，三维试验与PCR检测具有良好的一致性，产AmpC酶和ESBLs酶是阴沟肠杆菌耐药的主要原因。

OBJECTIVE To investigate the prevalence of β- lactarnases in nosocomial infections of Enterobacter cloacae, study the different g,enotyping of β-lactamases, and analyze its independence in drug resistance. METHODS AmpC β-lactamases and ESBLs were detected by three-dimensional extract tests. PCR was used to determine the genotype of β-1actamases and their resistance to 13 kinds of antibiotics was detected by Kirby-Bauer method. RESULTS The sensitivity test showed that they were resistant to the most antibiotics. Among the 80 ESBLs strains, 29 strains carried ESBLs gene,3 strains carried two different gene. Such as..TEM existed in 6, SHV-I existed in 2, CTX-M-2 existed in 5, CTX-M-3 existed in 8 and CTX-M-9 existed in 11 strains. Twenty-six strains carried ampC. The resistant rate of SSBLs-producing E. cloacae to 12 antibiotics except merapenem was 66.7-100. 0%. SSBLs strains of E. cloacae were higher than AmpC β-lactamases in resistance to levofloxacin, cefepime, aztronem and trimethoprim sulpfamethoxazole with significant difference （P〈0. 05）; SSBLs strains showed higher resistance than ESBLs to Meropenem （P〈0.05）. CONCLUSIONS This study shows that there are multiple-drug resistance and high degree of drug resistance in E. cloacae isolates. CTX-m is the main type of ESBLs. The accordance of three-dimensional extract tests and PCR is perfect. AmpC-lactamases and ESBLs are severe and prevalent. Producing ApmC and ESBLs enzyme is the prominent cause of resistance in E. cloacae.