Survey on Legionella pneumophila in Water Supply Systems of Qazvin Hospitals

Abstract

Hospital infections are one of the important causes of hospital mortality and Legionella pneumophila bacteria is considered as one of the common causes of hospital infection. The natural habitat of these bacteria in aquatic environments and can tolerate different environmental conditions in terms of pH, temperature, oxygen content and nutrients. Therefore, this study aimed to identify Legionella pneumophila in aquatic systems of hospital environments. This descriptive cross-sectional study was performed in the summer of 2017 to identify Legionella pneumophila in hot and cold water systems of important and critical parts of Qods and Kosar Hospital. A total of 120 samples were collected, and after filtration, heat treatment, and acidic treatment, all the samples are cultured on BCYE agar enriched with GPVC supplement, and after incubation, the bacterial growth is investigated. Legionella suspected colonies were approved by complementary tests and their assignment to Legionella was confirmed. The water samples were also investigated for temperature, pH, and residual chlorine (using a DPD kit). The frequency of Legionella pneumophila bacteria in water supply systems of Qods Hospital was zero in all hot and cold water showers of NICU, PICU 1, PICU 2, Hematology and Oncology sectors. The frequency of this bacterium was zero in postpartum, childbirth, and women's surgery sectors, but it was positive in the hot and cold water showers of the prenatal sector (8 CFU ml^-1 and 8.33 CFU ml^-1, respectively) and neonatal sector (4 CFU ml^-1 and 4.16 CFU ml^-1, respectively). Although Qods and Kosar Hospitals use the treated water of urban distribution network, 24 cases (40%) of contamination were found in water supply systems of Kosar Hospital, and this contamination can be attributed to reasons such as low residual chlorine content, and appropriate temperature range for growth of this bacteria.