BACKGROUND Methicillin-susceptible Staphylococcus aureus (MSSA) is a frequent cause of bloodstream infections (BSI). Treatment with nafcillin (NAF) has been preferred to cefazolin (CFZ). However, comparable outcomes have been found with CFZ with possibly lower risk for side-effects. This study compared safety and effectiveness of NAF versus CFZ for MSSA BSI. METHODS This single center retrospective study evaluated adults admitted with MSSA BSI who received NAF or CFZ. Patients receiving ≥24 h of antibiotics were included for safety analyses. Patients receiving NAF or CFZ for ≥75% of a 14 day minimum treatment course were assessed for clinical effectiveness. The primary safety outcome was incidence of renal toxicity with multiple secondary safety endpoints. Clinical success was defined as symptom resolution, repeat negative cultures, lack of additional therapy for presumed failure, and lack of recurrence within 30 days. RESULTS A total of 130 patients receiving NAF (n = 79) or CFZ (n = 51) were included for safety analysis. Of those, 90 met criteria for effectiveness assessment (NAF n = 40, CFZ n = 50). Baseline characteristics were well matched. NAF was associated with a higher incidence of nephrotoxicity compared to CFZ (25% vs. 2%, RR 1.31, 95% CI 1.15-1.5, p < 0.001), allergic reactions (p = 0.01) and a trend for hepatotoxicity (p = 0.08). Clinical success was achieved in 82% NAF and 94% CFZ treated patients (p = 0.1). CONCLUSION CFZ was associated with less nephrotoxicity and no difference in clinical success compared to NAF for MSSA BSI. A prospective study comparing NAF to CFZ for MSSA BSI should be conducted to elucidate differences in therapies.

中文翻译：

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头孢唑林与纳夫西林治疗甲氧西林敏感性金黄色葡萄球菌血流感染的安全性和疗效比较。

背景技术对甲氧西林敏感的金黄色葡萄球菌（MSSA）是血流感染（BSI）的常见原因。相对于头孢唑林（CFZ），首选用那夫西林（NAF）治疗。但是，已经发现CFZ的可比结局具有较低的副作用风险。这项研究比较了MSA BSI的NAF和CFZ的安全性和有效性。方法这项单中心回顾性研究评估了接受NAF或CFZ的MSSA BSI入院的成年人。接受≥24 h抗生素治疗的患者被纳入安全性分析。评估接受NAF或CFZ至少14天最小疗程的75％的患者的临床有效性。主要的安全性结局是具有多个次要安全性终点的肾毒性发生率。临床成功定义为症状缓解，重复阴性培养，缺乏用于推测失败的其他疗法，并且在30天内没有复发。结果共纳入130名接受NAF（n = 79）或CFZ（n = 51）的患者以进行安全性分析。其中，有90个符合有效性评估标准（NAF n = 40，CFZ n = 50）。基线特征匹配良好。与CFZ相比，NAF的肾毒性发生率更高（25％vs.2％，RR 1.31，95％CI 1.15-1.5，p <0.001），过敏反应（p = 0.01）和肝毒性趋势（p = 0.08）。在82％的NAF和94％的CFZ治疗的患者中取得了临床成功（p = 0.1）。结论与NAF相比，CFZ与MSA BSI的肾毒性较小且临床成功率无差异。应该进行一项针对NASA与CFZ进行MSSA BSI比较的前瞻性研究，以阐明治疗方法的差异。