Effect of extremely low-concentration gaseous chlorine dioxide against surface Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii in wet conditions on glass dishes

OBJECTIVE: Healthcare-associated infections due to Gram-negative bacteria (GNB) are a major cause of mortality and morbidity throughout the world. The purpose of the research described here was to evaluate the possibility of using an extremely low-concentration gaseous chlorine dioxide (ClO(2), 0.01 ppmv, 0.028 mg/m(3)) as a technique to reduce the risk of environmental infection by GNB. In this study we set up an exposure chamber (1 m(3)) and used three types of GNB, namely Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii. RESULTS: The extremely low-concentration gaseous ClO(2) inactivated E. coli (> 2 log(10) reductions, within 2 h), P. aeruginosa (> 4 log(10) reductions, within 2 h) and A. baumannii (> 2 log(10) reductions, within 3 h) in wet conditions on glass dishes. Treatment of moist environments with extremely low-concentration gaseous ClO(2) may help to reduce the risk of environmental infection by GNB without harmful effects.