耐药柠檬酸杆菌属β-内酰胺酶检测

Detection of Beta-lactamases in Multi-resistant Citrobacter Strains

目的了解安徽医科大学第一附属医院临床分离的耐药柠檬酸杆菌属产β-内酰胺酶的情况。方法采用琼脂稀释法测定17种抗菌药物对临床分离的52株柠檬酸杆菌最低抑菌浓度(MIC),用改良三维试验检测31株柠檬酸杆菌ESBLs、AmpC、MBL的产酶情况,再用聚合酶链反应(PCR)法扩增β-内酰胺酶基因。结果31株柠檬酸杆菌对多种抗菌药物耐药,三维试验检出24株菌产ESBLs,3株菌产AmpC酶,2株同时高产AmpC酶和ESBLs,未检出MBL;PCR检出20株菌携带blaTEM基因,1株菌携带blaSHV基因,8株菌携带blaCTX-M-1基因,15株菌携带blaCTX-M-13基因,5株菌携带blaCIT基因。结论31株多重耐药的柠檬酸杆菌同时产>1种的ESBLs及高产AmpC酶,是其对β-内酰胺类药物耐药的重要原因。

OBJECTIVE To investigate beta-lactamases production in multi-resistant Citrobacter strains isolated from the First Affiliated Hospital of Anhui Medical University. METHODS Standard agar dilution method was used to determine the minimal inhibitory concentration （MIC） of 52 clinically isolated Citrobacter strains, improved three-dimensional tests were performed to detect the ESBLs-producing, AmpC-producing and MBL- producing strains in 31 Citrobacter isolates, then heta-lactamases-encoding genes were amplified by polymerase chain reaction （PCR）. RESULTS Thirty one Citrobacter strains were resistant to many beta-lactams antibiotics. Twenty four strains ESBLs-producing, 3 AmpC-producing and 2 ESBLs-producing plus AmpC-producing strains have been detected by improved three-dimensional tests, and not found MBL-producing ones. Twenty strains had blaTEM gene and 1 strain had blaSHV gene, 8 strains had blaCTX-M-1 gene, 15 strains had blacTX-M-13 gene and 5 strains had blaciT gene by PCR. CONCLUSIONS Multi-resistant Citrobacter strains produce one or more types of ESBLs and AmpC heta-lactamase, it may he an important reason of resistance to heta-lactams antibiotics.