Kasuga Eriko, Matsumoto Takehisa, Hidaka Eiko, Oguchi Harumi, Kanai Shinichiro, Oana Kozue, Yamauchi Kazuyoshi, Honda Takayuki, Kawakami Yoshiyuki
Department of Laboratory Medicine, Shinshu University Hospital, and Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University School of Medicine.
Rinsho Biseibutshu Jinsoku Shindan Kenkyukai Shi. 2009;20(1-2):1-8.
Extended-Spectrum beta-Lactamase (ESBL)-producers in the family Enterobacteriaceae are recognized worldwide as nosocomial pathogens, however it is difficult to screen them in the routine laboratory processing. ChromID ESBL agar newly developed for screening ESBL-producing Enterobacteriaceae was released in Japan in April, 2007. We evaluated the clinical assessment of ChromID ESBL agar in routine microbiology laboratory. The 47 strains investigated were clinical isolates belonging to the family Enterobacteriaceae with the MICs of cefpodoxime greater than 2 mug/ml. The 27 ESBL-producers examined were comprising of 19 Escherichia coli, 3 Klebsiella oxytoca, 1 Citrobacter freundii, 3 Enterobacter cloacae, and 1 S. marcescens (ESBL group) and 20 ESBL non-producers consiating of 5 K. oxytoca, 1 Proteus mirabilis, 1 P. vlugaris, 2 Serratia marcescens, 8 C. freundii, 2 Enterobacter cloacae, and 1 E. aerogenes (non-ESBL group). Characterization of beta-lactamase genes was carried out by use of polymerase chain reaction. As the results, the sensitivity and the specificity of ChromID ESBL agar plates after incubation for 18 hours was 100% and 20%, respectively. It should be noted that the values of specificity was extremely low compared with those of the sensitivity. These findings clearly suggested that in cases of utilizing ChromID ESBL agar plates, it should be important to consider its characteristic properties, as even the ESBL-non-producers could grow on these media only when they were resistant to CPDX.
肠杆菌科中的超广谱β-内酰胺酶（ESBL）产生菌在全球范围内被公认为医院病原体，然而在常规实验室检测中很难对其进行筛查。2007年4月，新开发的用于筛查产ESBL肠杆菌科细菌的ChromID ESBL琼脂在日本上市。我们评估了ChromID ESBL琼脂在常规微生物实验室中的临床应用价值。所研究的47株菌株为肠杆菌科临床分离株，头孢泊肟的最低抑菌浓度（MIC）大于2μg/ml。检测的27株产ESBL菌株包括19株大肠埃希菌、3株产酸克雷伯菌、1株弗氏柠檬酸杆菌、3株阴沟肠杆菌和1株粘质沙雷氏菌（ESBL组），以及20株非产ESBL菌株，包括5株产酸克雷伯菌、1株奇异变形杆菌、1株普通变形杆菌、2株粘质沙雷氏菌、8株弗氏柠檬酸杆菌、2株阴沟肠杆菌和1株产气肠杆菌（非ESBL组）。通过聚合酶链反应对β-内酰胺酶基因进行鉴定。结果显示，孵育18小时后的ChromID ESBL琼脂平板的敏感性和特异性分别为100%和20%。需要注意的是，与敏感性相比，特异性的值极低。这些结果清楚地表明，在使用ChromID ESBL琼脂平板时，考虑其特性非常重要，因为即使是非产ESBL菌株，只有在对头孢泊肟耐药时才能在这些培养基上生长。
