University Medical Center New Orleans, New Orleans, Louisiana, USA.
University Medical Center New Orleans, New Orleans, Louisiana, USA; University of Louisiana Monroe College of Pharmacy, Monroe, Louisiana, USA.
Clin Ther. 2024 Jun;46(6):444-450. doi: 10.1016/j.clinthera.2024.01.012. Epub 2024 Mar 15.
Coagulase-negative staphylococci (CoNS) are Gram-positive organisms that are a known component of normal skin flora and the most common cause of nosocomial bacteremia. For CoNS species, the vancomycin MIC breakpoint for susceptibility set by the Clinical and Laboratory Standards Institute is ≤4 µg/mL. There has been published reports of vancomycin heteroresistance in CoNS with vancomycin MICs of 2 to 4 µg/mL. The aim of this retrospective cohort analysis was to assess the clinical impact of vancomycin MICs <2 µg/mL versus ≥2 µg/mL in adult patients with CoNS bloodstream infections.
Adult patients admitted to University Medical Center New Orleans with a blood culture positive for CoNS were assessed. The primary outcome was difference in 30-day mortality. Secondary outcomes were in-hospital, all-cause mortality; duration of bacteremia; hospital length of stay; and percentage of oxacillin-resistant CoNS.
There was no difference in mortality in the vancomycin MIC <2 µg/mL group versus the vancomycin MIC ≥2 µg/mL group at 30 days (15.4% vs 17.4%; P = 1). In-hospital, all-cause mortality was also not different between groups (11.5% vs 13%; P = 1). Hospital length of stay between groups was 28.2 days versus 21 days (P = 0.692). Median duration of bacteremia was 1 day in both groups (P = 0.975), and median scheduled duration of antibiotic therapy was 14.9 days and 19.5 days (P = 0.385). The source and mode of acquisition of CoNS were similar between groups. Of all CoNS isolates, 58.7% (44 of 75) were oxacillin resistant. Staphylococcus epidermidis was the most common CoNS species at 66.7% (50 of 75). Of all isolates, 30.7% (23 of 75) had a vancomycin MIC ≥2 µg/mL, and 87% (20 of 23) of these were S. epidermidis. There was a higher percentage of S. epidermidis in the vancomycin MIC ≥2 µg/mL group than in the MIC <2 µg/mL group (87% vs 57.7%; P = 0.012). CoNS with a vancomycin MIC ≥2 µg/mL were also more likely to be oxacillin resistant (78.3% vs 50%; P = 0.005).
There was no difference in clinical outcomes in adult patients with a CoNS bloodstream infection with a vancomycin MIC <2 µg/mL versus ≥2 µg/mL. At present, vancomycin remains appropriate empiric therapy for CoNS bloodstream infection. Further research is needed to determine if there is a true clinical impact of a vancomycin MIC ≥2 µg/mL in CoNS infections.
凝固酶阴性葡萄球菌（CoNS）是一种革兰氏阳性菌，是正常皮肤菌群的已知组成部分，也是医院获得性菌血症的最常见原因。对于 CoNS 物种，临床和实验室标准协会（CLSI）设定的万古霉素 MIC 折点为 ≤4 µg/mL，用于判断敏感性。已经有报道称 CoNS 中存在万古霉素异质性耐药，万古霉素 MIC 为 2 至 4 µg/mL。本回顾性队列分析的目的是评估 CoNS 血流感染患者中万古霉素 MIC <2 µg/mL 与 ≥2 µg/mL 对临床的影响。
评估了在奥尔良大学医学中心因 CoNS 血液培养阳性而入院的成年患者。主要结局是 30 天死亡率的差异。次要结局为住院、全因死亡率；菌血症持续时间；住院时间；和耐苯唑西林 CoNS 的百分比。
万古霉素 MIC <2 µg/mL 组与万古霉素 MIC ≥2 µg/mL 组在 30 天的死亡率无差异（15.4% vs 17.4%；P = 1）。两组间住院期间、全因死亡率也无差异（11.5% vs 13%；P = 1）。两组间住院时间分别为 28.2 天和 21 天（P = 0.692）。两组的菌血症持续时间中位数均为 1 天（P = 0.975），计划抗生素治疗的中位持续时间分别为 14.9 天和 19.5 天（P = 0.385）。CoNS 的来源和感染途径在两组间相似。所有 CoNS 分离株中，58.7%（44/75）为耐苯唑西林。表皮葡萄球菌是最常见的 CoNS 物种，占 66.7%（50/75）。所有分离株中，30.7%（23/75）的万古霉素 MIC ≥2 µg/mL，其中 87%（20/23）为表皮葡萄球菌。万古霉素 MIC ≥2 µg/mL 组的表皮葡萄球菌比例高于 MIC <2 µg/mL 组（87% vs 57.7%；P = 0.012）。万古霉素 MIC ≥2 µg/mL 的 CoNS 也更有可能耐苯唑西林（78.3% vs 50%；P = 0.005）。
在万古霉素 MIC <2 µg/mL 与 ≥2 µg/mL 的 CoNS 血流感染患者中，临床结局无差异。目前，万古霉素仍是 CoNS 血流感染的经验性治疗药物。需要进一步研究以确定 CoNS 感染中万古霉素 MIC ≥2 µg/mL 是否具有真正的临床影响。
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