抗生素性腹泻肠道杆菌产超广谱β-内酰胺酶基因型的调查

Genotyping of extended-spectrum β-lactamase-producing enterobacteriaceae isolated from patients with antibiotic-associated diarrhea

目的:研究抗菌药物使用后,引起腹泻患者肠道杆菌产超广谱β-内酰胺酶(ESBLs)细菌的耐药基因型并进行序列分析.方法:收集临床住院应用抗菌药物后出现腹泻患者的大便或肛拭子进行培养,分离产ESBLs的肺炎克雷伯菌50株、大肠埃希菌21株和变形杆菌18株,通过改良Hodge实验、EDTA双纸片增效试验、分别测定KPC、金属酶;聚合酶链反应(PCR)检测其耐药基因、分析PCR产物序列并在GenBank中比对分析,总结产ESBLs细菌同源性的和变异情况.结果:89株产ESBL的菌株中,有64株携带CTX型耐药基因,68株携带TEM型耐药基因,21株携带SHV型耐药基因.肺炎克雷伯菌中CTX型占到84%(42/50),TEM型占到76%(38/50),SHV型占到15%(7/50);变形杆菌中没有SHV型,而TEM型占到100%(18/18),CTX型占到40%(7/18);大肠埃希菌中CTX占到100%(21/21),SHV型和TEM型均为83%(17/21);同时检出3株产KPC和22株产金属酶的细菌.结论:本院抗生素腹泻患者肠道杆菌产ESBLs耐药基因主要以CTX和TEM为主,同时携带两个或两个以上耐药基因的细菌占49%(44/89).

AIM： To genotype extended-spectrum β-lactamase （ESBL）-producing enterobacteriaceae isolated from patients with antibiotic-associated diarrhea. METHODS： The feces samples were collected from patients with antibiotic-associated diarrhea and cultured to isolate ESBL-producing enterobacteriaceae. Klebsiella pneumoniae carbapenemase production was evaluated by the modified Hodge test. Metallo-β-lactamase production was determined by the imipenem-EDTA doubledisk synergy test. Antibiotic resistance genes were amplified by polymerase chain reaction （PCR）. The sequences of PCR products were determined and compared with those deposited in GenBank. RESULTS： Fifty Klebsiella pneumoniae strains, 21 Escherichia coli strains and 18 Proteus strains were isolated. Of all isolated strains, 64 carry ESBLs of the CTX-type, 68 carry ESBLs of the TEM-type, and 21 carry ESBLs of the SHV-type. CTX-, TEM- and SHV-type ESBLs were present in 84% （42/50）, 76% （38/50） and 15% （7/50） of Klebsiella pneumoniae isolates, respectively. TEM- and CTX-type ESBLs were present in 100% （18/18） and 40% （7/18） of Proteus isolates, respectively. No SHV-type ESBLs were detected in Proteus isolates. CTX-, TEM- and SHV-type ESBLs were present in 100% （21/21）, 83% （17/21） and 83% （17/21） of Escherichia coli isolates, respectively. CONCLUSION： The enterobacteriaceae isolated from patients with antibiotic-associated diarrhea in our study mainly carry TEM- and CTX-type ESBLs.