Massive hospital-wide bacillus outbreak related to hospital linen and construction

Results B. cereus complex constituted 164 cases (71.3%). Bacteraemia comprised 207 patient episodes (90.0%), of which 124 occurred in immunocompromised patients or those with intravascular devices. Physicians treated the organism in 68 episodes (29.5%). Environmental investigations confirmed heavy air contamination particularly within patient rooms and air conditioned wards. Dense airborne contamination outside the hospital adjacent to large earthworks on a construction site was demonstrated (~600CFU/m). Towels were heavily contaminated even after laundering (7403±1054 spores/cm). Amplification of spores occurred in clean linen due to storage conditions (165±84 spores/cm pre-storage vs 4437±1228 spores/cm post-storage). Interventions focusing on laundry protocols, environmental cleaning and air filtration saw clinical case numbers return to baseline levels within three months. Conclusion Environmental contamination with Bacillus may be an under-recognised infection risk in hospitals exposed to construction work. Laundering and environmental cleaning processes that are not sporicidal carry a greater risk. Storage conditions of cleaned linen can amplify Bacillus contamination.