Department of Microbiology, Wellington Southern Community Laboratories, Wellington, New Zealand.
Department of Infection Services, Wellington Regional Hospital, Wellington, New Zealand.
J Antimicrob Chemother. 2023 Nov 6;78(11):2715-2722. doi: 10.1093/jac/dkad288.
Positive culture results from non-sterile sites (NSSs) are poorly predictive of clinical infection. Despite this, these results are often interpreted as an indication for antibiotics, even in patients with limited signs of infection. We sought to quantify the influence of NSS culture results on post-report antibiotic initiation (PRAI) in patients who had not been started on antibiotics pre-report.
All community wound/skin swab and sputum cultures were matched to antibiotic dispensing records from February 2017 to July 2022. Prescribing behaviour was assessed pre- and post-report. Sampling without treatment pre-report was termed 'test-and-wait' (TaW). Following TaW, PRAI was identified if antibiotics were started within 5 days post-report.
There were 65 480 wound/skin swabs and 8126 sputum samples, with TaW occurring in 21 740 (35.1%) and 4185 (54.4%), respectively. Following a TaW approach PRAI occurred in 43.3% when an organism was reported, versus 10.8% (P < 0.01) for a 'no growth' report for wound/skin swabs. For the same comparison with sputum, PRAI occurred in 47.9% versus 10.8% (P < 0.01). On multivariate analysis reporting an organism remained strongly associated with PRAI.
Reporting an organism in those not already on antibiotics was strongly associated with PRAI. We hypothesize that for many patients TaW suggests limited evidence of infection (i.e. insufficient to justify antibiotic treatment at time of sampling), meaning positive NSS results may be driving a considerable volume of potentially unnecessary antibiotic use. Further study on this topic is required, but strategies to reduce PRAI may offer laboratories an opportunity to meaningfully impact antimicrobial stewardship efforts.
非无菌部位（NSS）的阳性培养结果对临床感染的预测作用较差。尽管如此，这些结果通常被解释为使用抗生素的指征，即使在感染症状有限的患者中也是如此。我们试图量化 NSS 培养结果对报告后抗生素起始（PRAI）的影响，这些患者在报告前没有开始使用抗生素。
从 2017 年 2 月至 2022 年 7 月，所有社区伤口/皮肤拭子和痰培养均与抗生素配药记录相匹配。在报告前和报告后评估了处方行为。报告前未治疗的采样被称为“测试和等待”（TaW）。在 TaW 之后，如果在报告后 5 天内开始使用抗生素，则确定是否发生 PRAI。
共有 65480 例伤口/皮肤拭子和 8126 例痰样本，分别有 21740（35.1%）和 4185（54.4%）例进行了 TaW。采用 TaW 方法，当报告有细菌时，PRAI 发生率为 43.3%，而报告“无生长”时，PRAI 发生率为 10.8%（P<0.01）。对于痰标本的相同比较，PRAI 发生率分别为 47.9%和 10.8%（P<0.01）。在多变量分析中，报告细菌与 PRAI 强烈相关。
在未使用抗生素的患者中报告细菌与 PRAI 强烈相关。我们假设，对于许多患者，TaW 表明感染的证据有限（即采样时不足以证明需要抗生素治疗），这意味着 NSS 的阳性结果可能导致大量潜在不必要的抗生素使用。需要进一步研究这一主题，但减少 PRAI 的策略可能为实验室提供一个有意义的机会，以影响抗菌药物管理工作。
