Microbial contamination of water-soaked cotton gauze and its cause

Seven in-use cotton gauze samples and three cotton balls soaked in sterile distilled water in canisters were investigated 7 days after they were prepa red in hospital. All samples were contaminated with bacteria including 10(6 ) to 10(7) colony forming units/ml of Pseudomonas aeruginosa. In vitro viab ility tests using cotton gauze and cotton balls soaked in sterile distilled water revealed rapid proliferation of Fl aeruginosa, Serratia marcescens a nd Candida albicans. Since the cotton gauze and the cotton balls were soake d in water containing nutrients, such as protein and glucose, these materia ls may be readily contaminated with bacteria including P. aeruginosa. Thus, when using cotton gauze and cotton balls containing water, microbial conta mination should be expected.