Evaluation of Updated Interpretative Criteria for Categorizing Klebsiella pneumoniae with Reduced Carbapenem Susceptibility
Evaluation of Updated Interpretative Criteria for Categorizing Klebsiella pneumoniae with Reduced Carbapenem Susceptibility
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DOI：
10.1128/jcm.02458-09
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发表时间：
2010-12-01
影响因子：
9.4
通讯作者：
Jacobs, Michael R.
中科院分区：
文献类型：
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作者：
Endimiani, Andrea;Perez, Federico;Jacobs, Michael R.
我们研究了各种药敏试验方法的准确性，包括2009年、2010年和2010年更新的CLSI建议，以确定与不同耐药机制相关的对碳青霉烯类抗生素敏感性降低的肺炎克雷伯菌分离株。对43株野生型(WT)菌株、42株超广谱β-内酰胺酶(ESBL)产生菌、18株外膜孔蛋白缺失的ESBL产生菌(ESBL/OMP菌株)和42株肺炎克雷伯菌(KPC-KP)进行了评估。采用肉汤微量稀释法(BMD)、Etest法和纸片扩散法(DD)对亚胺培南(IPM)、美罗培南(MEM)、厄他培南(ERT)和多利培南(DOR)进行检测，并用IPM和MEM纸片进行改良Hodge试验(MHT)。根据最初和最近更新的解释标准对结果进行了解释。42株KPC-KP和18株ESBL/OMP中10株MHT均为阳性，因此对KPC-KP和ESBL/OMP分离株的鉴别特异性较差。根据最新的CLSI标准，BMD和DD的表型药敏试验区分了大多数碳青霉烯类敏感的肺炎克雷伯菌和不敏感的碳青霉烯类肺炎克雷伯菌，而不需要MHT，而Etest方法则将许多KPC-KP分离株鉴定为敏感，这种方法可能需要降低断裂点。然而，原始和更新的CLSI标准都没有充分区分KPC-KP组和ESBL/OMP组的菌株，KPC-KP组的菌株不太可能对碳青霉烯治疗有反应，如果MIC在药代动力学/药效学目标范围内，ESBL/OMP组的菌株可能对碳青霉烯治疗有反应。需要进一步的研究来确定是否有临床需要区分KPC-KP和ESBL/OMP组。
We studied the accuracy of various susceptibility testing methods, including the 2009, 2010, and updated 2010 CLSI recommendations, to identify Klebsiella pneumoniae isolates with reduced susceptibility to carbapenems associated with different mechanisms of resistance. Forty-three wild-type (WT) strains, 42 extended-spectrum beta-lactamase (ESBL) producers, 18 ESBL producers with outer membrane porin protein loss (ESBL/Omp strains), and 42 bla(KPC)-possessing K. pneumoniae (KPC-Kp) isolates were evaluated. Imipenem (IPM), meropenem (MEM), ertapenem (ERT), and doripenem (DOR) were tested by broth microdilution (BMD), Etest, and disk diffusion (DD), and the modified Hodge test (MHT) was performed using IPM and MEM disks. Results were interpreted according to original as well as recently updated interpretative criteria. MHT was positive for all 42 KPC-Kp isolates and 10 of 18 ESBL/Omp strains and therefore had poor specificity in differentiating between KPC-Kp and ESBL/Omp isolates. Based on the updated CLSI standards, phenotypic susceptibility testing by BMD and DD differentiated most carbapenem-susceptible from carbapenem-nonsusceptible K. pneumoniae isolates without the need for MHT, while the Etest method characterized many KPC-Kp isolates as susceptible, and breakpoints may need to be lowered for this method. However, both the original and updated CLSI criteria do not adequately differentiate between isolates in the KPC-Kp group, which are unlikely to respond to carbapenem therapy, and those in the ESBL/Omp group, which are likely to respond to carbapenem therapy if MICs are within pharmacokinetic/pharmacodynamic targets. Further studies are required to determine if there is a clinical need to differentiate between KPC-Kp and ESBL/Omp groups.