Performance of an Agar Dilution Method and a Vitek 2 Card for Detection of Inducible Clindamycin Resistance in Staphylococcus spp.
Performance of an Agar Dilution Method and a Vitek 2 Card for Detection of Inducible Clindamycin Resistance in Staphylococcus spp.
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DOI：
10.1128/jcm.01751-09
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发表时间：
2010-04-01
影响因子：
9.4
通讯作者：
Labbe, Annie-Claude
中科院分区：
文献类型：
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作者：
Lavallee, Christian;Rouleau, Danielle;Labbe, Annie-Claude
D区带试验检测葡萄球菌属中诱导型克林霉素耐药性。临床和实验室标准协会（CLSI）未描述的另外两种方法可用于检测这种耐药机制：琼脂稀释法和新Vitek 2卡。本研究评价了这两种方法在检测诱导型克林霉素耐药中的性能。葡萄球菌属的非重复临床菌株。(111金黄色葡萄球菌和52个凝固酶阴性菌株），对红霉素中等或耐药但对克林霉素敏感，从加拿大魁北克蒙特利尔的三家医院获得。对所有菌株进行分子分析以检测抗性基因。使用含有1 mg红霉素和0.5 mg克林霉素/L的Mueller-Hinton琼脂进行稀释法，并检测两种接种物：10（4）和10（5）CFU/斑点。在24和48 h读取平板。根据制造商的建议使用Vitek 2 AST-P580卡。并与D区试验结果进行比较。D区带试验阳性134/163株（82%）。在10（4）CFU接种物下，24和48 h时的灵敏度分别为84%和99%。105 CFU接种物使24和48 h的灵敏度分别增加至91%和100%。24 h时10（4）CFU接种物的特异性为100%，其他组合的特异性为97%。Vitek 2卡的灵敏度和特异性分别为93%和100%。琼脂稀释法和Vitek 2卡的性能良好，但这些方法在24 h时不如D-区带试验灵敏。
The D-zone test detects inducible clindamycin resistance in Staphylococcus spp. Two other methods not described by the Clinical and Laboratory Standards Institute (CLSI) are available to test for this resistance mechanism: an agar dilution method and new Vitek 2 cards. This study evaluated the performance of both methods in detecting inducible clindamycin resistance. Nonduplicate clinical strains of Staphylococcus spp. (111 Staphylococcus aureus and 52 coagulase-negative staphylococcus strains), intermediate or resistant to erythromycin but susceptible to clindamycin, were obtained from three hospitals in Montreal, Quebec, Canada. Molecular analysis to detect resistance genes was conducted on all strains. A Mueller-Hinton agar containing 1 mg of erythromycin and 0.5 mg of clindamycin/liter was used for the dilution method, and two inocula were tested: 10(4) and 10(5) CFU per spot. Plates were read at 24 and 48 h. The Vitek 2 AST-P580 card was used according to the manufacturer's recommendations. The results were compared to those of the D-zone test. The D-zone test was positive in 134 of 163 (82%) strains. With the 10(4) CFU inoculum, the sensitivities were 84 and 99% at 24 and 48 h, respectively. The 105 CFU inoculum increased the sensitivities at 24 and 48 h to 91 and 100%, respectively. The specificity was 100% for the 10(4) CFU inoculum at 24 h and 97% for the other combinations. The sensitivity and specificity for the Vitek 2 card were 93 and 100%, respectively. The performance of both the agar dilution method and the Vitek 2 card was good, but these methods were not as sensitive as the D-zone test at 24 h.