Effectiveness of Hydrogen Peroxide Nebulization Combined with Manual Cleaning in Reducing Surface-Associated Microorganisms in an Indoor Fitness Environment

Fitness centers represent high-contact environments where microorganisms can accumulate and persist on shared surfaces. This study aimed to investigate bacterial contamination dynamics on gym equipment and evaluate the effects of hydrogen peroxide (H2O2) nebulization combined with preceding professional manual cleaning on the recovery of viable surface-associated microorganisms. A two-phase investigation was conducted in a commercial fitness facility. Repeated environmental sampling was performed on 12 gym devices over five consecutive days at three daily timepoints (morning, midday, evening), followed by a pre–post assessment of the combined terminal decontamination procedure. All isolates were recovered using culture-based methods and identified by MALDI TOF MS. Species were classified by ecological origin, and persistence, diversity, and intervention effects were quantified using ecological metrics. Statistical analyses were performed in R. Across all samples, 248 isolates representing 61 species were detected, with the recovered isolates predominantly belonging to skin-associated families including Micrococcaceae (25.4%), Staphylococcaceae (24.2%), and Moraxellaceae (22.2%). Routine cleaning with an alcohol-based cleaner produced only modest reductions in recovered bacterial isolate counts (p = 0.173), with 68% of environmental species no longer recovered after routine cleaning, whereas 93% of skin-associated species remained detectable following routine cleaning. In contrast, the terminal decontamination procedure consisting of professional manual cleaning followed by H2O2 nebulization resulted in 88% of detected species no longer being recovered after treatment, with no Gram-negative species recovered in post-treatment cultures, while only three Gram-positive species (Staphylococcus epidermidis, Staphylococcus hominis, and Dietzia cinnamea) continued to be recovered after treatment. Contamination levels and persistence patterns varied markedly across devices. Gym equipment surfaces repeatedly yielded predominantly human-derived communities of recoverable viable bacteria despite routine cleaning. The combined terminal decontamination procedure produced greater reductions in recoverable bacterial species than routine overnight cleaning under the conditions evaluated, supporting further investigation of this combined intervention as a supplemental terminal decontamination strategy for high-traffic fitness environments.