Department of Pharmacy Practice, Western New England University College of Pharmacy, Springfield, Massachusetts, USA.
J Clin Microbiol. 2013 Sep;51(9):2837-42. doi: 10.1128/JCM.00768-13. Epub 2013 Jun 19.
We evaluated the evolution of vancomycin MICs for Staphylococcus aureus and their relationship with vancomycin use among hospitalized children. S. aureus isolates recovered from sterile sites were prospectively tested for vancomycin susceptibility using the Etest between 1 April 2000 and 31 March 2008. Vancomycin MICs were grouped into three categories: ≤ 1, 1.5, and 2 μg/ml. The association between vancomycin MICs and aggregate vancomycin use and individual patient vancomycin exposure 6 months prior to the documented infection was assessed. The geometric mean values for vancomycin MICs for S. aureus fluctuated over time without a significant trend (P = 0.146). Of the 436 patients included in the study, 363 (83%) had methicillin-susceptible S. aureus (MSSA) and 73 (17%) had methicillin-resistant S. aureus (MRSA) infections. The rate of isolates with a vancomycin MIC of 2 μg/ml increased from 4% (2 of 46) in 2000 to 2001 to 24% (11 of 46) in 2007 to 2008, despite a decrease in vancomycin use (r = -0.11; P = 0.825). The percentage of isolates with a vancomycin MIC of 2 μg/ml was higher for MRSA (15%; 11 of 73) than for MSSA strains (5.2%; 19 of 363) (χ(2) = 9.2; P = 0.01). Individual patient vancomycin exposure was not associated with a higher vancomycin MIC. In the unadjusted model, in which we compared patients with S. aureus infections with MICs of ≤ 1 μg/ml, the odds ratios of exposure rates for patients with isolates with MICs of 1.5 μg/ml and 2 μg/ml were 1.02 (P = 0.929) and 1.13 (P = 0.767), respectively. In our experience, the geometric means of vancomycin MICs from S. aureus isolates recovered from hospitalized children oscillated over time and were not associated with previous individual patient vancomycin exposure or aggregate vancomycin use.
我们评估了金黄色葡萄球菌万古霉素 MIC 的演变及其与住院患儿万古霉素使用之间的关系。2000 年 4 月 1 日至 2008 年 3 月 31 日期间，前瞻性地使用 Etest 测试从无菌部位分离的金黄色葡萄球菌分离株对万古霉素的敏感性。万古霉素 MIC 分为三组：≤1、1.5 和 2μg/ml。评估了万古霉素 MIC 与汇总万古霉素使用和个体患者在记录感染前 6 个月暴露于万古霉素之间的关系。万古霉素 MIC 的几何平均值随时间波动，但无明显趋势（P = 0.146）。在纳入研究的 436 名患者中，363 名（83%）为耐甲氧西林金黄色葡萄球菌（MSSA），73 名（17%）为耐甲氧西林金黄色葡萄球菌（MRSA）感染。万古霉素 MIC 为 2μg/ml 的分离株率从 2000 年至 2001 年的 4%（46 株中的 2 株）增加到 2007 年至 2008 年的 24%（46 株中的 11 株），尽管万古霉素使用量减少（r = -0.11；P = 0.825）。万古霉素 MIC 为 2μg/ml 的分离株率在 MRSA（15%；73 株中的 11 株）中高于 MSSA 株（5.2%；363 株中的 19 株）（χ(2) = 9.2；P = 0.01）。个体患者万古霉素暴露与万古霉素 MIC 升高无关。在未调整的模型中，我们将金黄色葡萄球菌感染患者与 MIC 值≤1μg/ml 的患者进行比较，MIC 值为 1.5μg/ml 和 2μg/ml 的患者的暴露率比值分别为 1.02（P = 0.929）和 1.13（P = 0.767）。根据我们的经验，从住院患儿中分离出的金黄色葡萄球菌分离株的万古霉素 MIC 的几何平均值随时间波动，与先前个体患者万古霉素暴露或汇总万古霉素使用无关。
