INIQUI   05448
INSTITUTO DE INVESTIGACIONES PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Fungi in drinking water distribution systems during a stagnation period
Autor/es:
SANGUINO JORQUERA DIEGO; CRUZ, MERCEDES CECILIA; CORIMAYO SHEILA; RAJAL, VERONICA; APARICIO GONZALEZ MONICA
Reunión:
Congreso; Congreso Conjunto de la Sociedad Argentina de Investigación Bioquímica (SAIB) y la Asociación Civil de Microbiología General (SAMIGE).; 2020
Institución organizadora:
SAIB-SAMIGE
Resumen:
Fungi survive under different environmental conditions, including oligotrophic ecosystems such as chlorinated drinking water distribution systems (DWDS). These organisms can be found in the bulk water causing unpleasant odors, clogged pipes, paint deterioration, and they can grow on the surface of inner-wall pipes forming biofilms. Therefore, they could harbor pathogens, increase resistance to antibiotics and disinfectant tolerance. These organisms can also produce mycotoxins thatare harmful to human health. Furthermore, stagnation periods could enhance those undesirable effects. The objective of this work was to evaluate the presence of fungi in DWDS using traditional cultivation techniques. A total of 48 water samples were collected monthly from six taps points of different buildings, an elevated distribution tank, and the cistern located at a university campus, in a period of six months (March to August 2020) with low water consumption. To determine the abundance of fungi, drinking water samples of 100 mL were concentrated by a membrane filtration method and cultured on Sabouraud Glucose Agar medium at 30 oC for seven days. The grown colonies were isolated in the same medium, and their macro- and microscopic characteristics were examined. In addition, 1 L of water was collected from each site for microbiological and physicochemical analysis, which included the determination of indicator bacteria and opportunistic pathogens (total coliforms, E. coli, and P. aeruginosa), the quantification of heterotrophic bacteria on Plate Count Agar, and the measurement of temperature, conductivity, salinity, pH, and free chlorine. The eight sites showed different physicochemical characteristics. Chlorine concentration varied significantly (0.2 mg/L - 1.5 mg/L) among the studied sites. As expected, because of seasonality, the temperature decreased along with the study. The bacteriological quality of the drinking water was acceptable for consumption according to the current legislation. No significant correlations were found between the physicochemical and bacteriological variables and the abundance of fungi (p-value > 0.05). Of the total of samples, 89.6% (43/48) presented fungi. The average abundance of fungi in the DWDS was 62.8 CFU/mL, while the highest number of fungi determined was 825 CFU/mL in one site in May. Three Fungi genera were constantly observed in one of the sampled points; meanwhile, the other sites showed a more diverse fungal community during the monthly monitoring. The results showed that fungi are widely found in the DWDS, and changes in their abundance and diversity can be expected at different sites throughout stagnation periods. The occurrence of fungi in water has no relationship with indicator bacteria tested according to the current legislation. More studies are required to know the potential impact of fungi on infrastructure and consumers.