Hospital Elevators as Critical Microenvironments for Microbial Exposure: Integrating Air Quality, Surface Contamination and Antimicrobial Resistance into Environmental Risk Assessment

This study examined the microbial quality of air and surfaces in six elevators at a tertiary hospital in Greece in 2022. The results highlighted hospital elevators as potentially relevant environmental reservoirs of microbial contamination, with contact surfaces (buttons) exhibiting significantly higher microbial loads than the air. Strong seasonality was also documented; the elevated microbial burden observed during the October sampling period likely reflects seasonal fluctuations in occupant traffic and environmental factors, although direct traffic and microclimatic variables were not monitored. Presumptive Staphylococcus spp. strains dominated the air, while Gram-negative bacteria recovered on MacConkey agar prevailed on surfaces. Phenotypically resistant isolates were also detected, including isolates showing reduced susceptibility or resistance to clinically relevant antimicrobial agents, highlighting the potential value of incorporating AMR surveillance into environmental monitoring. The semi-quantitative environmental exposure assessment showed that, while air quality remained within acceptable limits, the surface-contact route via elevator buttons represented the largest estimated exposure component. Healthcare workers showed the highest estimated cumulative exposure because of the greater frequency of elevator use assumed in the exposure scenario. In conclusion, hospital elevators may act as environmental reservoirs of microbial contamination and potential exposure pathways within the hospital environment, highlighting the need for enhanced hygiene measures, systematic monitoring and the integration of antimicrobial resistance into exposure assessment.