Clinical Microbiology, MTC, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
Clin Microbiol Infect. 2011 May;17(5):668-74. doi: 10.1111/j.1469-0691.2010.03299.x.
The aim of this study was to compare CLSI and EUCAST MIC and disk diffusion carbapenem breakpoints for the detection of carbapenemase-producing Klebsiella pneumoniae. K. pneumoniae strains with known KPC (n = 31) or VIM (n = 20) carbapenemases were characterized by disk diffusion (Oxoid) and Etest (bioMérieux) vs. imipenem, meropenem and ertapenem, and with VITEK2 (bioMérieux, five different cards). Extended-spectrum β-lactamase (ESBL) testing was performed with VITEK2 (bioMérieux), ESBL combination disks (Becton Dickinson) and the ESBL Etest (bioMérieux). With CLSI and EUCAST MIC breakpoints, respectively, 11 and seven of the strains were susceptible to imipenem, 12 and eight to meropenem, and seven and none to ertapenem. The EUCAST epidemiological cut-off (ECOFF) values for meropenem and ertapenem identified all carbapenemase producers, whereas the imipenem ECOFF failed in five strains. All carbapenemase producers were detected with EUCAST disk diffusion breakpoints for ertapenem and meropenem, and four strains were susceptible to imipenem. CLSI disk diffusion breakpoints characterized 18 (imipenem), 14 (meropenem) and three (ertapenem) isolates as susceptible. When cards with a single carbapenem were used, detection failures with VITEK2 were four for imipenem, none for meropenem and one for ertapenem. Cards containing all three carbapenems had one to two failures. With ESBL combination disks, 21/31 KPC producers and 2/20 VIM producers were positive. With VITEK2, no VIM producers and between none and seven KPC producers were ESBL-positive. All carbapenemase producers were detected with the meropenem MIC ECOFF, or the clinical EUCAST breakpoint for ertapenem. EUCAST disk diffusion breakpoints for meropenem and ertapenem detected all carbapenemase producers. VITEK2 had between none and four failures in detecting carbapenemase producers, depending on the antibiotic card.
本研究旨在比较 CLSI 和 EUCAST MIC 和纸片扩散碳青霉烯类药物折点，以检测产碳青霉烯酶肺炎克雷伯菌。通过纸片扩散法（Oxoid）和 Etest（bioMérieux）对已知产 KPC（n=31）或 VIM（n=20）碳青霉烯酶的肺炎克雷伯菌菌株进行表型特征分析，药敏试验采用亚胺培南、美罗培南和厄他培南，同时采用 VITEK2（bioMérieux，五种不同卡片）。采用 VITEK2（bioMérieux）、ESBL 联合药敏纸片（Becton Dickinson）和 ESBL Etest（bioMérieux）进行超广谱β-内酰胺酶（ESBL）检测。分别采用 CLSI 和 EUCAST MIC 折点，11 株和 7 株对亚胺培南敏感，12 株和 8 株对美罗培南敏感，7 株和 0 株对厄他培南敏感。EUCAST 流行病学折点（ECOFF）值可用于美罗培南和厄他培南，可识别所有产碳青霉烯酶的细菌，而亚胺培南 ECOFF 对 5 株菌不敏感。所有产碳青霉烯酶的细菌都可通过 EUCAST 纸片扩散折点检测到，对厄他培南和美罗培南敏感，4 株对亚胺培南敏感。CLSI 纸片扩散折点将 18 株（亚胺培南）、14 株（美罗培南）和 3 株（厄他培南）分离物鉴定为敏感。当使用仅含一种碳青霉烯类药物的卡片时，VITEK2 对亚胺培南的检测失败有 4 例，对美罗培南无失败，对厄他培南有 1 例失败。含三种碳青霉烯类药物的卡片失败 1-2 例。采用 ESBL 联合药敏纸片时，31 株 KPC 产酶菌中有 21 株阳性，20 株 VIM 产酶菌中有 2 株阳性。采用 VITEK2 检测时，VIM 产酶菌无一例阳性，KPC 产酶菌中有 0-7 例阳性。所有产碳青霉烯酶的细菌都可通过美罗培南 MIC ECOFF 或临床 EUCAST 厄他培南折点检测到。EUCAST 纸片扩散折点对美罗培南和厄他培南检测所有产碳青霉烯酶的细菌均敏感。VITEK2 检测产碳青霉烯酶的细菌时，根据药敏卡片的不同，有 0-4 例失败。
