Frequency of virulent Legionella pneumophila in hospitalwater supply systems in the west of Iran

Background and Aim : Legionella pneumophila as a fastidious rod-shaped aerobic and Gramnegativebacterium causes hospital-acquired pneumonia. Hospital water supply systems are knownas long-term and critical reservoirs in the human infectious cycle. This study aims to detect thefrequency of L. pneumophila. in water supply systems of hospitals of Sanandaj city in the west ofIran.Methods : In a cross-sectional study, ۱۰۰ water samples (۵۰-۱۰۰۰ cc) were collected from ۱۰۰different sites of hospital water supply systems. Following separation of sediments of watersamples by using centrifuge machine and heat treating, the sediments were processed by usingculture and direct PCR methods to detect Legionella spp.Results : The frequency of Legionella spp. isolated from the water samples by using culture onBCYE agar and PCR method (۱۶s rDNA gene specific primers for Legionella spp.) was ۱۲% and۱۶%, respectively. The most isolates of Legionella spp. were detected by using direct PCR on thewater samples collected from shower head (n ۷) and water pond (n ۴) (p<۰.۰۵). In this meanwhile,the frequency of mip and rtxA virulence genes by using direct PCR was ۲۵% (۴/۱۶) and ۲۵%(۴/۱۶), respectively. Based on the results of Hippurate hydrolysis tests and ۱۶s rDNA genesequencing, ۴ isolates grown on the BCYE were L. pneumophila which showed frequency ۱۰۰%of mip and rtxA virulence genes (۴/۴).Conclusion : This study showed the high frequency of virulent L. pneumophila and its virulencegenes in water supply systems of hospitals in the west of Iran.

کلیدواژه ها:

Legionella ، mip ، rtxA ،