Investigation of Fungal contamination in Drinking Water Distribution Systems of Selected Hospitals in City of Tehran in 2019

Background and Objectives: Waterborne fungi might lead to occurring of symptoms such as skin irritations and allergic reactions, an enhanced occurrence of opportunistic systematic mycosis in immunocompromised patients, taste and odor problems and contamination in food and drinking water. Therefore, attention had been drawn to the presence, identification, and count of waterborne fungi, as a nosocomial agent, in drinking water sources, bottled mineral water, tap water, and drinking water distribution systems. The main goal of this study was to investigate the presence, identification, and count of waterborne fungiin the drinking water distribution system of selected hospitals in the city of Tehran. Materials and Methods: In this analytical study, random sampling was used. 44 samples were taken from cold and warm drinking water distribution system of selected hospitals in different areas in the city of Tehran, from March to July2019. The samples were collected in the sterile bottle according to the procedure detailed in national standard methods. We measured the fungi and heterotrophic plate count (HPC) by using pour plate (9610 B and 9215 B methods) and polymerase chain reaction methods. We measured the physicochemical parameters such as pH, turbidity, residual chlorine, temperature, total organic carbon, electrical conductivity, phosphorus, acidity, calcium, and copper according to procedures detailed in standard methods for the examination of water and wastewater.We employed the geographical information system (GIS) software package ArcGIS 9.2 for mapping and analyzing the data for the investigation of drinking water distribution system quality in hospitals. The relationship between the variables was defined by using chi-square test, Pearson correlation and ANOVA methods. Results: The pH, turbidity, residual chlorine, temperature, total organic carbon, electrical conductivity, phosphorus, acidity, calcium, and copper range of 22 cold water samples were 7-7.8 (7.4±0.2), 0-1.5 (0.8±0.4) NTU, 0-1.5 (0.6±0.4) mg/l, 12-27 (20.1±4.8)̊ C, 0.51-0.74 (0.73±0.16) mg/l, 153-923 (574.1±255.8) μmoh/cm, 0.17-0.46 (0.85±0.45) mg/l, 60-280 (166.4±65.5) mg as CaCO3/l, 170-230 (222.5±27.5) mg as CaCO3/l, and 24-31 (27.6±4.2) μg/l, respectively. The pH, turbidity, residual chlorine, temperature, total organic carbon, electrical conductivity, phosphorus, acidity, calcium, and copper range of 22 hot water samples were7.1-7.9 (7.5±0.2), 0.1-1.6 (0.8±0.4) NTU, 0-0.8 (0.3±0.2) mg/l, 23-56 (33.4±7.8)̊ C, 0.52-0.75 (0.74±0.16) mg/l, 154-924 (575.1±255.8) μmoh/cm, 0.18-0.47 (0.86±0.45) mg/l, 61-281 (167.4±65.5) mg as CaCO3/l, 171-231 (223.5±27.5) mg as CaCO3/l, and 25-32 (28.6±4.2) μg/l, respectively. The frequency of fungal contamination of 22 cold water samplesby culture and PCR methods was 0 and 1, respectively. The frequency of fungal contamination 22 hot water samples by culture and PCR methods was1 and 2, respectively. The HPC mean of 22 cold and hot water samples by culture method was 0 and 6.1±1.4 (0-29) CFU/ml, respectively. Conclusion: The mean colony forming unit of warm water samples is higher than cold water samples. PCR method was more efficient and more sensitive than culture. Preventive strategies planning to reduce the exposure risk to fungi in water sources is proposed to public health authorities.