肠杆菌科菌株产A类碳青霉烯酶检测

Determination of A-Carbapenemase-producing Isolates in Species of Enterobacteriaceae

目的调查肠杆菌科细菌产A类碳青霉烯酶的现状。方法纸片扩散法和微量肉汤稀释法两种常规药敏试验作为初筛试验、改良Hodge试验作为表型确认试验。结果在598株耐三代头孢菌素及碳青霉烯药物的肠杆菌科细菌，以三代头孢菌素、亚胺培南、美罗培南、厄他培南为底物，初筛试验两种方法阳性菌株数分别为569，-，29，29；551，z9，28，28，确认试验阳性菌株数分别为13，21，22，24。四种底物确认试验阳性率分别为2．28％（13／569），72．41％（21／29），75．86％（22／29），82．76％（24／29），厄他培南捡出率最高。8株菌同时产A类碳青霉烯酶与ESBL，6株菌同时产A类碳青霉烯酶和质粒AmpC酶，没有菌株同时产这3种酶。结论表型确认试验操作简便，适合各级医院常规开展肠杆菌科细菌A类碳青霉烯酶检测，可为临床合理应用抗菌药物、控制感染和流行病学研究提供依据。

Objective To investigate the current situation of producing A-carbapenemase in species of Enterobacteriaceae. Methods Routine antibiotic susceptibility tests including the disk diffusion and the broth microdilution were used for initial screen test. The Modified Hodge test was used for the phenotypic confirmatory test. Results In the 598 of third-generation cephalosporins and carbapenemase resistant Enterobacteriaceae strains, third generation cephalosporin, imipenem, meropenem and ertapenem were used as substrates,the positive isolates of two methods of the initial screen tests were 569, -, 29,29 and 551,29,28,28, respectively. The positive isolates of the phenotypie confirmatory tests were 13,21,22, 24, respectively. The positive rate of four substrates of the phenotypic confirmatory tests were 2.28%（13/569）,72.41% （21/29）, 75.86% （22/29） and 82.76 % （24/29） ,respectively. The detection rate of ertapenem was the highest. Eight clinical isolates produced A-carbapenemase and extended-spectrum β-lactamase,six clinical isolates produced A-carbapenemase and plasmid AmpC β-lactamase,there was no isolate produceing three types β-lactamase simultaneously. Conclusion The test procedure of phenotypic confirmatory test is simple and suitable for detecting A-carbapenemase-producing clinical isolates in routine in all degrees of hospitals. It can provide evidence for the rational application of antibacterials,appropriate infection control and epidemiologic studies.