金黄色葡萄球菌β-内酰胺酶表型检测方法比较
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摘要
目的评价几种金黄色葡萄球菌β-内酰胺酶表型检测方法的差异。方法收集自动化仪器检测青霉素最小抑菌浓度(MIC)≤0.12和≥0.25μg/mL的金黄色葡萄球菌38株和15株。分别采用青霉素抑菌圈边缘试验(P1、P10)、头孢硝噻吩显色试验和"四叶草"试验检测β-内酰胺酶。采用聚合酶链反应(PCR)扩增blaZ基因,并以基因检测方法为标准,评价几种检测方法的差异。结果 38株MIC≤0.12μg/mL的菌株中有2株抑菌圈直径(P10)为27 mm。检出blaZ基因阳性菌株15株,分别为2株青霉素MIC=0.12μg/mL和13株青霉素MIC≥0.25μg/mL的菌株。15株blaZ基因检测阳性菌株青霉素抑菌圈边缘试验均为阳性,敏感性为100%;头孢硝噻吩显色试验和"四叶草"试验阳性各14株,敏感性为93.3%。38株blaZ基因检测阴性的菌株中,"四叶草"试验阳性3株,特异性为92.1%;头孢硝噻吩显色试验和青霉素抑菌圈边缘试验阳性各为2株,特异性为94.7%。结论几种常见β-内酰胺酶表型检测方法均具有较高的敏感性和特异性,临床可根据实际需求进行选择。
Objective To compare the phenotypic methods for β-lactamase detection in Staphylococcus aureus.Methods A total of 38 isolates with penicillin minimum inhibitory concentration(MIC)≤0.12 μg/mL and 15 isolates with penicillin MIC≥0.25 μg/mL were collected. Penicillin zone edge test(P1 and P10),nitroce?n test and clover test were used for β-lactamase detection. Polymerase reaction chain(PCR) was used for amplifying blaZ gene. The gene detection method was used as standard,and the difference among these methods were evaluated.Results Among the 38 isolates with MIC≤0.12 μg/mL,by penicillin zone edge test(P10),2 isolates produced27 mm diameter of inhibition zone. Totally,15 isolates were positive for blaZ gene,including 2 isolates with MIC=0.12 μg/m L and 13 isolates with MIC≥0.25 μg/m L. Among the 15 isolates,the penicillin zone edge test showed all sensitive(100%). The nitroce?n test and clover test detected 14 isolates,and the sensitivity was 93.3%. There were 38 isolates being negative for blaZ gene,the nitroce?n test and penicillin zone edge test detected 2 isolates,and the speci?city was 94.7%,while clover test detected 3 isolates,and the speci?city was 92.1%. Conclusions The phenotypic methods mentioned above are speci?c and sensitive,which can be used according to clinical needs.
Objective To compare the phenotypic methods for β-lactamase detection in Staphylococcus aureus.Methods A total of 38 isolates with penicillin minimum inhibitory concentration(MIC)≤0.12 μg/mL and 15 isolates with penicillin MIC≥0.25 μg/mL were collected. Penicillin zone edge test(P1 and P10),nitroce?n test and clover test were used for β-lactamase detection. Polymerase reaction chain(PCR) was used for amplifying blaZ gene. The gene detection method was used as standard,and the difference among these methods were evaluated.Results Among the 38 isolates with MIC≤0.12 μg/mL,by penicillin zone edge test(P10),2 isolates produced27 mm diameter of inhibition zone. Totally,15 isolates were positive for blaZ gene,including 2 isolates with MIC=0.12 μg/m L and 13 isolates with MIC≥0.25 μg/m L. Among the 15 isolates,the penicillin zone edge test showed all sensitive(100%). The nitroce?n test and clover test detected 14 isolates,and the sensitivity was 93.3%. There were 38 isolates being negative for blaZ gene,the nitroce?n test and penicillin zone edge test detected 2 isolates,and the speci?city was 94.7%,while clover test detected 3 isolates,and the speci?city was 92.1%. Conclusions The phenotypic methods mentioned above are speci?c and sensitive,which can be used according to clinical needs.
引文
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[3]CHONG Y P,PARK S J,KIM E S,et al.Prevalence of blaZ gene types and the cefazolin inoculum effect among methicillin-susceptible Staphylococcus aureus blood isolates and their association with multilocus sequence types and clinical outcome[J].Eur J Clin Microbiol Infect Dis,2015,34(2):349-355.
[4]Clinical and Laboratory Standards Institute.Performance standards for antimicrobial susceptibility testing[S].M100-S26,CLSI,2016.
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[6]LIVORSI D J,CRISPELL E,SATOLA S W,et al.Prevalence of blaZ gene types and the inoculum effect with cefazolin among bloodstream isolates of methicillinsusceptible Staphylococcus aureus[J].Antimicrob Agents Chemother,2012,56(8):4474-4477.
[7]PAPANI COLASL E,BELLJ M,B A S T I A N I.Performance of phenotypic tests for detection of penicillinase in Staphylococcus aureus isolates from Australia[J].J Clin Microbiol,2014,52(4):1136-1138.
[8]HOMBACH M,WEISSERT C,SENN M M,et al.Comparison of phenotypic methods for the detection of penicillinase in Staphylococcus aureus and proposal of a practical diagnostic approach[J].J Antimicrob Chemother,2017,72(4):1089-1093.
[9]OLSEN J E,CHRISTENSEN H,AARESTRUP F M.Diversity and evolution of blaZ from Staphylococcus aureus and coagulase-negative staphylococci[J].J Antimicrob Chemother,2006,57(3):450-460.
[2]FERREIRA A M,MARTINS K B,SILVA V R,et al.Correlation of phenotypic tests with the presence of the blaZgene for detection of beta-lactamase[J].Braz J Microbiol,2017,48(1):159-166.
[3]CHONG Y P,PARK S J,KIM E S,et al.Prevalence of blaZ gene types and the cefazolin inoculum effect among methicillin-susceptible Staphylococcus aureus blood isolates and their association with multilocus sequence types and clinical outcome[J].Eur J Clin Microbiol Infect Dis,2015,34(2):349-355.
[4]Clinical and Laboratory Standards Institute.Performance standards for antimicrobial susceptibility testing[S].M100-S26,CLSI,2016.
[5]European Committee on Antimicrobial Susceptibility Testing.Breakpoint tables for interpretation of MICs and zone diameters.Version 7.1[Z].http:www.eucast.org,2017.
[6]LIVORSI D J,CRISPELL E,SATOLA S W,et al.Prevalence of blaZ gene types and the inoculum effect with cefazolin among bloodstream isolates of methicillinsusceptible Staphylococcus aureus[J].Antimicrob Agents Chemother,2012,56(8):4474-4477.
[7]PAPANI COLASL E,BELLJ M,B A S T I A N I.Performance of phenotypic tests for detection of penicillinase in Staphylococcus aureus isolates from Australia[J].J Clin Microbiol,2014,52(4):1136-1138.
[8]HOMBACH M,WEISSERT C,SENN M M,et al.Comparison of phenotypic methods for the detection of penicillinase in Staphylococcus aureus and proposal of a practical diagnostic approach[J].J Antimicrob Chemother,2017,72(4):1089-1093.
[9]OLSEN J E,CHRISTENSEN H,AARESTRUP F M.Diversity and evolution of blaZ from Staphylococcus aureus and coagulase-negative staphylococci[J].J Antimicrob Chemother,2006,57(3):450-460.