革兰阴性杆菌产超广谱β-内酰胺酶的分布及基因型

Distribution and genotype of extended-spectrum beta-lactamases in gram-negative rods

目的了解临床分离的革兰阴性杆菌中产ESBLs的流行特征及ESBLs基因型.方法对我院临床分离的革兰阴性杆菌,采用改良三维试验检测产ESBLs菌株,用PCR对ESBLs基因进行分型.结果175株革兰阴性杆菌分离出49株产ESBLs菌,阳性率28%,包括大肠埃希菌、克雷伯菌属、阴沟肠杆菌、弗劳地枸椽酸杆菌、铜绿假单胞菌、鲍曼不动杆菌.其中,第一位是阴沟肠杆菌(34.7%,17/49),其次是大肠埃希菌(30.6%,15/49).每种细菌产ESBLs率前三位是阴沟肠杆菌(56.6%,17/30),大肠埃希菌(37.5%,15/40),肺炎克雷伯菌(25.0%,6/24).各病区中神经科产ESBLs菌分离率最高(32.7%).49株产ESBLs菌携带TEM,SHV,CTX-M分别为34,5,16株,有17株同时携带两种β-内酰胺酶基因的菌株,占34.7%,其中TEM+CTX-M型13株,占基因双阳性菌株的76.5%.结论我院产ESBLs菌以阴沟肠杆菌、大肠埃希菌为主.神经科是主要产ESBLs菌的病区.ESBLs基因以TEM型、CTX-M型为主,携带双基因的菌株在我院有流行.

AIM： To study the distribution characteristics of extended- spectrum beta-lactamases （ESBLs）-producing strains in the second hospital of Lanzhou University and the genotype of ESBLs. METHODS： The gram-negative rods were collected from the second hospital of Lanzhou University by the three-dimensional test. The genotype of ESBLs was confirmed by PCR sequencing. RESULTS： 49 ESBLs-producing strains （28%） were found from 175 strains including E. cloacae,E, coli, K. pneumoniae, C. freundii, P. aeruginosa and A. baumanii. The most common isolates were E. cloacae（34.7%, 17/49） and E. coli（ 30. 6% , 15/49）. The first three isolates with the highest ESBLs-producing rate were E. cloacae （ 56. 6%, 17/30 ）, E. coli （ 37. 5%, 15/40 ） and K. pneumoniae（ 25.0%, 6/24 ）. The ward with the highest ESBLs-producing rate（32.7% ） was the Department of Neurology . PCR products revealed that 34 strains harbored TEM type, 5 strains SHV type and 16 strains CTX-M using their specific primers. 17 strains （34.7%） with two kinds of 13-1actamase genes （mainly TEM ＋ CTX-M type, 13 strains, 76.5% ） were found from the 49 ESBLs-producing isolates. CONCLUSION： E. cloacae and E. coli are the most common bacterias producing ESBLs. The Department of Neurology is the ward with the highest ESBLs producing rate. The ESBLs producing isolates mainly carried TEM and CTX-M resistant genes. The isolates with double ESBLs genes are found prevalent in our hospital.