Hand hygiene versus continued glove use in simulated nursing care: a crossover study on microbial kinetics and unintended transmission

Healthcare workers’ (HCWs) hands are primary vectors for pathogen transmission. While non-sterile examination gloves (NSG) are intended to protect against contamination, they are often perceived as a substitute for hand disinfection (HD). This crossover simulation study in student nurses compared the microbial kinetics of once-disinfected bare hands versus continued NSG use and explored unintended Staphylococcus aureus transmission between participants. Using a crossover design, twenty-five student nurses performed standardised nursing tasks on manikins under both conditions in randomised order: (i) NSG worn continuously for 45 min without change; (ii) HD with an alcohol-based hand rub immediately before tasks (no gloves). Hand-impression cultures were taken at 0, 5, 15, 25, 35 and 45 min, plate-reading after 24 and 48 h. Counts > 100 CFU were capped at 100. Behaviour was video monitored. Group differences were analysed using the Wilcoxon signed-rank test with Bonferroni correction; S. aureus detection (≥ 1 positive timepoint per arm) was compared by McNemar’s exact test. In the HD arm, mean CFU increased from 1.7 ± 3.3 (baseline) to 31.8 ± 30.4 at 5 min and then plateauing around 40–45 CFU for 15–45 min. In the NSG arm, CFU progressively accumulated, reaching 76.7 ± 29.1, 77.1 ± 27.7 and 81.0 ± 27.7 at 25, 35 and 45 min, respectively. From 25 min onwards, NSG counts were significantly higher than HD counts ( p = 0.0007, 0.0012 and 0.0003; Bonferroni-corrected α = 0.0083). S. aureus (all methicillin-susceptible) was detected in at least one timepoint in 21/25 (84%) NSG-arm participants versus 9/25 (36%) HD-arm participants (McNemar p = 0.0005). Notably, one baseline nasal carrier, following an observed incomplete HD event, contaminated two co-workers via a shared manikin within 5 min, demonstrating HCW-to-HCW spread in the HD arm. Once-disinfected hands rapidly return to a stable resident microbiome level, whereas continued NSG use without glove changing leads to progressive microbial accumulation and substantially higher S. aureus carriage. NSG must not replace HD and require a change interval of 15–20 min, followed by HD after removal. HD must be performed correctly immediately before patient contact.