Department of Pharmacy, Upstate University Hospital, Syracuse, NY, USA.
Binghamton University School of Pharmacy and Pharmaceutical Sciences, Binghamton, NY, USA.
Ann Pharmacother. 2023 Jun;57(6):669-676. doi: 10.1177/10600280221127389. Epub 2022 Oct 2.
Skin and soft tissue infections (SSTIs) are often caused by gram-positive bacteria that colonize the skin. Given the overuse of antibiotics, SSTIs are increasingly caused by resistant bacteria, including methicillin-resistant (MRSA). Guidance on the utility of MRSA nasal screening for MRSA SSTI is limited.
To determine whether MRSA nasal screening predicts the risk of MRSA SSTIs.
This was a single-center, retrospective cohort study of adult patients with an SSTI diagnosis that had MRSA nasal screening and wound cultures obtained within 48 hours of starting antibiotics. Sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratios were calculated using VassarStats. Pretest and posttest probabilities were estimated with Microsoft Excel.
A total of 884 patient encounters were reviewed between December 1, 2018, and October 31, 2021, and 300 patient encounters were included. The prevalence of MRSA SSTI was 18.3%. The MRSA nasal colonization had a sensitivity of 63.6%, specificity of 93.9%, positive predictive value of 70.0% (95% CI = 55.2%-81.7%), negative predictive value of 92.0% (95% CI = 87.7%-94.9%), positive likelihood ratio of 10.39 (95% CI = 6.12-17.65), negative likelihood ratio of 0.39 (95% CI = 0.27-0.55), positive posttest probability of 70.0%, and negative posttest probability of 8.0%.
Given the high positive likelihood ratio, a positive MRSA nasal screen was associated with a large increase in the probability of MRSA SSTI at our institution, and a negative MRSA nasal screen was associated with a small but potentially significant decrease in the probability of MRSA SSTI.
皮肤和软组织感染（SSTIs）通常由定植于皮肤的革兰氏阳性菌引起。鉴于抗生素的过度使用，SSTIs 越来越多地由耐药菌引起，包括耐甲氧西林金黄色葡萄球菌（MRSA）。关于 MRSA 鼻腔筛查对 MRSA SSTI 的效用的指南有限。
确定 MRSA 鼻腔筛查是否可预测 MRSA SSTI 的风险。
这是一项单中心、回顾性队列研究，纳入了在开始使用抗生素的 48 小时内接受了 MRSA 鼻腔筛查和伤口培养的 SSTI 诊断的成年患者。使用 VassarStats 计算了敏感性、特异性、阳性和阴性预测值以及阳性和阴性似然比。使用 Microsoft Excel 估算了术前和术后的概率。
在 2018 年 12 月 1 日至 2021 年 10 月 31 日期间，共回顾了 884 例患者就诊记录，其中纳入了 300 例患者就诊记录。MRSA SSTI 的患病率为 18.3%。MRSA 鼻腔定植的敏感性为 63.6%，特异性为 93.9%，阳性预测值为 70.0%（95%CI=55.2%-81.7%），阴性预测值为 92.0%（95%CI=87.7%-94.9%），阳性似然比为 10.39（95%CI=6.12-17.65），阴性似然比为 0.39（95%CI=0.27-0.55），阳性术后概率为 70.0%，阴性术后概率为 8.0%。
鉴于高阳性似然比，本机构中阳性的 MRSA 鼻腔筛查与 MRSA SSTI 概率的大幅增加相关，而阴性的 MRSA 鼻腔筛查与 MRSA SSTI 概率的微小但具有潜在显著降低相关。
