Microbiological evaluation of protected environments during patient occupancy

Area of Science:

• Infection Control
• Environmental Microbiology
• Clinical Engineering

Background:

• Cancer chemotherapy patients are highly susceptible to infections.
• Maintaining sterile environments is critical for reducing infection risk in immunocompromised individuals.
• Conventional hospital rooms pose a higher risk of microbial exposure.

Purpose of the Study:

• To compare microbial contamination levels in different patient isolation environments.
• To assess the effectiveness of laminar airflow (LAF) rooms and life island (LI) units in controlling airborne and surface microorganisms.
• To identify sources of persistent contamination within protected environments.

Main Methods:

• Conducted microbiological monitoring in occupied LAF rooms, LI units, and regular hospital rooms.
• Sampled air for organism counts (organisms per 1,000 ft³).
• Analyzed floor samples for sterility and organism deposition rates on settling plates.

Main Results:

• LAF rooms had significantly lower organism counts (5/1,000 ft³) than LI units (31/1,000 ft³) and hospital rooms (>3,000/1,000 ft³).
• Over 70% of LAF room floor samples were sterile, contrasting with hospital rooms where none were sterile.
• LAF rooms exhibited slower organism deposition rates (1 organism/4.5 hr) compared to hospital rooms (1 organism/0.08 hr).
• Potential pathogens were more frequent in hospital room samples.
• Persistent contamination sites in LAF rooms included flooring and water supply.
• Over 50% of potential pathogens in protected units originated from the patients themselves.

Conclusions:

• LAF rooms and LI units offer superior microbial control compared to standard hospital rooms for chemotherapy patients.
• While effective, LAF rooms require attention to potential contamination sources like flooring and water systems.
• Patient-to-environment transmission is a significant factor in protected isolation units.