头孢西丁纸片法筛选产AmpC酶的不动杆菌

Screening of AmpC β-lactamases-producing Acinetobacter by cefoxitin disk

目的评价头孢西丁(FOX)纸片筛选法检测不动杆菌产头孢菌素β-内酰胺酶(AmpC酶)的可靠性。方法FOX纸片抑菌圈直径<18 mm为可疑产AmpC酶菌株,聚合酶链反应(PCR)扩增ampC基因阳性者为确证产AmpC酶。结果130株不动杆菌中,7株菌FOX筛选阴性,经PCR扩增ampC基因为阴性,证实其不产AmpC酶。123株不动杆菌FOX筛选阳性,其中ampC基因阳性者38株。FOX纸片筛选不动杆菌产AmpC酶的假阳性率为92.4%,不存在假阴性。结论FOX纸片筛选法检测产AmpC酶不动杆菌的特异性较差。

Objective To evaluate the reliability of cefoxitin （FOX） disk for screening AmpC β-1actamases produced by Acinetobacter. Methods The FOX inhibition diameter 〈 18 mm was identified as AmpC β-lactamases positive. Polymerase chain reaction （PCR） was used as confirmatory test. Results Among 130 strains, 7 strains were AmpC β-lactamases negative by FOX disk screen test, which were ampC gene negative by PCR. 123 trains were AmpC β-1actamases positive,in which 38 strains were ampC gene positive by PCR. The false-positive rate of FOX disk screening AmpC β-lactamases was 92.4%. There was no false-negative result. Conclusions FOX disk screen test has poor specificity in detecting AmpC β-lactamases produced by Acinetobacter.