Contamination of hospital linen by Bacillus cereus

Area of Science:

• Microbiology
• Hospital Infection Control
• Environmental Hygiene

Background:

• Post-operative meningitis cases were linked to Bacillus cereus (B. cereus) contamination.
• Hospital linen, laundered via a batch continuous washing machine, showed heavy B. cereus spore contamination.

Purpose of the Study:

• To identify the source of B. cereus spore contamination in hospital laundered linen.
• To evaluate the effectiveness of the washing process in eliminating B. cereus spores.

Main Methods:

• Investigated two cases of post-operative B. cereus meningitis.
• Analyzed hospital linen, washing machine, detergents, chemicals, and water supply for B. cereus.
• Assessed spore survival through heat disinfection and chemical treatment stages.

Main Results:

• The washing machine, detergents, additives, and water supply were ruled out as contamination sources.
• High B. cereus spore content persisted on linen post-washing, unaffected by heat or disinfectants.
• B. cereus multiplication likely occurred on stored, damp linen, especially in high ambient temperatures.

Conclusions:

• Standard laundry processes are insufficient to eliminate B. cereus spores from contaminated linen.
• Increased water flow in washing machines correlated with reduced B. cereus spore levels on laundered linen.
• Preventing multiplication on stored linen is crucial for controlling B. cereus contamination.