弗劳地柠檬酸杆菌β-内酰胺酶检测

Detection of the β-lactamases produced by Citrobacter freundii

目的探讨弗劳地柠檬酸杆菌所产各种β-内酰胺酶（β-lase）的分布情况。方法以头孢硝噻吩试验检测33株弗劳地柠檬酸杆菌所产β-lase，采用多底物纸片法（协同法、拮抗法）、AmpC酶检测法、碳青霉烯酶分类检测其所产各种β-lase。结果检出33株弗劳地柠檬酸杆菌，其中各种酶全阴菌为4株，29株检出β-lase，总检出率为87．9％（29／33）；头孢硝噻吩试验27株为阳性（81．8％）；29株产酶菌株中，产青霉素酶为2株，产头孢菌素酶为3株，产广谱酶为5株，产超广谱酶为11株，产超广谱酶＋AmpC酶为6株，ESBLs总产酶率51．5％，产碳青霉烯酶为2株（均为复合产超广谱酶＋金属酶）。结论弗劳地柠檬酸杆菌产β-lase率、ESBLs总产酶率和复合产酶率很高，产六种酶，以广谱酶、ESBLs为主。

Objective To study the classification of β-lactamases produced by Citrobacter freundii. Methods Detecting the β-Lactamases produced by 33 strains of Citrobacter freundii with nitrocefin test, a multi-disk test （synergy test , antagonize test for the inducible AmpC β-Lactamases （IABLs））, AmpC β-Lactamases （ABLs） phenotype test and extented-spectrum β-Lactamases （ESBLs） screening test, carbapenem- hydrolyzing β-Lactamases（CHBLs）. Results In the 33 strains, 29 strains produced the β-Lactamases （87.9%） ;in nitrocefin tests 27 of the 29 strains were position （ 81.8 % ） ; two strains produced penicillinases, 3 strains produced cephalosporinases, 5 strains produced broad-spectrum β-Lactamases, 11 strains produced ESBLs alone, 6 strains produced ESBLs ＋ high-product ABLs, the rate of ESBLs produced by the 33 strains of Citrobacter freundii is 51.5%, 2 strains produced CHBLs （all produced ESBLs＋ metallo-β-lactamase）. Conclusions The rate of β-Lactamases, rate of ESBLs and co-produced by the 33 strains of Citrobacter freundii is very high, Citrobacter freundii produce six kinds of β-Lactamases, mainly BSBLs and ESBLs.