فراوانی لژیونلا پنوموفیلا در شیر آب سرد و گرم و مخزن آب انکوباتورهای بخش نوزادان بیمارستانهای گیلان

Background and purpose: Nosocomial outbreaks of legionnaires’ diseases are usually related to contamination of water sources. This survey investigated the frequency of mip gene in cold and warm water taps and water containers of infant incubators containing legionella pneumophila in hospitals of Guilan province, Iran. Materials and methods: This cross-sectional study used 140 samples. They were collected directly from sterile containers and were concentrated by centrifuge, then transferred to buffered charcoal yeast extract including both L-cyctein, Fe2+ ,glycin, and vancomycin and were incubated for 2-4 days. DNA was extracted using boiling method and PCR was performed to investigate legionella, mip gene and bacterial contamination using different primers. Results: About 8.5% of the samples contained legionella pneumophila that 11.1% were isolated from infant incubators and 5.8% were found in hot and cold tap waters. Mip gene was found in 2.8% of the samples. One third of incubator’s legionella pneumophila and half of the legionella pneumophila in hot water taps contained mip gene while the samples from cold taps were not found with mip gene. About 87.2% of negative samples showed bacterial contamination. Conclusion: Today sterile water is used in incubators, however, legionella and bacterial contaminations are considerably high. This may be due to long-term storage of water in incubator container that is a predisposing factor for biofilm formation. In this study high temperature of hot water system and high rate of free residual chlorine in tap water system were the main causes of low rate legionella contamination which did not influence the contamination rate with other bacteria.