Risk factors for healthcare-associated infection and colonization of Serratia marcescens in neonates: a systematic review and meta-analysis

Following PRISMA guidelines, we searched PubMed, Web of Science, Wanfang, and CNKI databases from inception to April 25, 2025 for studies in English or Chinese, examining risk factors for S. marcescens infection or colonization in neonates. All reported risk factors were extracted, with those reported in ≥ 3 studies defined as primary outcomes, and those reported in two studies defined as secondary outcomes. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random- or fixed-effects models based on I² heterogeneity. Sensitivity and publication bias analyses were conducted.

Twelve studies were included. Prematurity (OR = 2.90, 95%CI: 2.12–3.96) and very low birth weight (VLBW) (OR = 2.34, 95%CI: 1.48–3.72) were key host-related risk factors. Invasive procedures, including oral/nasogastric tube (aOR = 5.10, 95% CI: 3.06–8.52), arterial catheterization, surgery, continuous positive airway pressure(CPAP), mechanical ventilation, and central venous catheterization (CVC), significantly increased risk. Antibiotic exposure (aOR = 2.04, 95% CI: 1.06–3.93) was a modifiable risk factor, while breastfeeding (OR = 0.45, 95% CI: 0.27–0.75) and vaginal delivery (aOR = 0.51, 95% CI: 0.34–0.76) were protective.