آلودگي ميكروبي مخازن مرطوب كننده اكسيژن در بيمارستانهاي تهران

Contamination of oxygen humidifier reservoirs in hospitals of Tehran

Oxygen is used as an acceptable therapeutic option. One way of oxygen-therapy is application of humidifier, but unfortunately contamination of humidifiers may infect patients. Survey of microbial contamination of oxygen humidifier reservoirs in selected hospitals of Tehran was the purpose of this study. One hundred and thirty samples of water in humidifiers from three general hospitals in Tehran were collected. Prevalence of microbial contamination and its severity was assessed by colony count. These samples were from internal medicine, ICU and CCU wards. All samples were inoculated on Brain-Heart Infusion agar and colony counts were performed The pure colonies were subcultured and isolated strains were determined by microbiological methods. Results showed that the rate of contamination was 90%. Mixed microbial contamination was evident in 56.5% of the samples. The contamination rate was varied from 63.6% to 100% in different wards. Colony counts were changed in the range of 100 to more than 105 CFU/ml. There were more than 10.5 CFU/ml in 23.2% of samples. The most common isolated strains were Staphylococcus saprophyticus, Proteus spp, Acinetobacter spp, E.coli, S.aureus, Diphteroid spp, Fungi, and Pseudomonas aeruginosa. According to the high incidence of contamination in humidifiers, especial attention is needed to prevent transmission of infection by these instruments.