Persistence of Biofilm-Forming and Multidrug-Resistant Staphylococcus aureus on High-Touch Hospital Surfaces Despite Routine Cleaning and Disinfection.

BACKGROUND

Contaminated hospital surfaces play a key role in the transmission of healthcare-associated infections (HAIs), particularly those caused by antimicrobial-resistant pathogens. Despite routine cleaning and disinfection, high-touch surfaces may remain reservoirs for multidrug-resistant organisms, including biofilm-forming Staphylococcus aureus.

METHODS

An environmental surveillance study was conducted in a single-bed room of an Internal Medicine ward in a hospital in Northern Italy. High-touch surfaces in the near-patient area and room furniture were sampled twice daily over one week, before and after routine cleaning/disinfection with chlorine-based agents (0.1-0.5% Cl). Cleaning effectiveness was evaluated using aerobic colony count (ACC) and detection of S. aureus as indicators of environmental hygiene, applying accepted microbiological benchmarks (ACC < 5 CFU/cm2; S. aureus < 1 CFU/cm2). S. aureus isolates were characterized by PFGE, spa typing, antimicrobial susceptibility testing, and biofilm production assays.

RESULTS

Mean ACC decreased significantly after cleaning/disinfection (10.06 ± 15.67 vs 2.89 ± 5.52 CFU/cm2; p < 0.001), with a substantial reduction in non-compliant samples. However, residual contamination persisted on high-touch surfaces. S. aureus was detected in 12/238 samples, including post-cleaning samples from the near-patient area. Molecular analysis identified four distinct strains; notably, a spa type t032 (MLST ST22) isolate-methicillin-resistant, multidrug-resistant, and a strong biofilm producer-persisted on the bedside table handle both before and after cleaning.

CONCLUSION

Routine cleaning and disinfection significantly reduce environmental bioburden but may not reliably eliminate biofilm-forming multidrug-resistant S. aureus from critical hand-contact surfaces. These findings highlight the need for continuous microbiological surveillance and targeted IPC interventions to address environmental reservoirs of antimicrobial resistance in healthcare settings.