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:
APARICIO GONZALEZ, MA; CRUZ, MC; CORIMAYO, SN; ROMANO ARMADA, N; SANGUINO JORQUERA, D; RAJAL, VB
Lugar:
Buenos Aires
Reunión:
Congreso; Congreso Conjunto de la Sociedad Argentina de Investigación Bioquímica (SAIB) y la Asociación Civil de Microbiología General (SAMIGE); 2020
Institución organizadora:
Sociedad Argentina de Investigación Bioquímica (SAIB) y la Asociación Civil de Microbiología General (SAMIGE).
Resumen:
Fungi survive under different environmental conditions, including oligotrophic ecosystems such as chlorinateddrinking water distribution systems (DWDS). These organisms can be found in the bulk water causing unpleasantodors, 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 organismscan also produce mycotoxins that are harmful to human health. Furthermore, stagnation periods could enhance thoseundesirable effects. The objective of this work was to evaluate the presence of fungi in DWDS using traditionalcultivation 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 toAugust 2020) with low water consumption. To determine the abundance of fungi, drinking water samples of 100 mLwere concentrated by a membrane filtration method and cultured on Sabouraud Glucose Agar medium at 30 o C forseven days. The grown colonies were isolated in the same medium, and their macro- and microscopic characteristicswere examined. In addition, 1 L of water was collected from each site for microbiological and physicochemicalanalysis, 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 oftemperature, conductivity, salinity, pH, and free chlorine. The eight sites showed different physicochemicalcharacteristics. Chlorine concentration varied significantly (0.2 mg/L - 1.5 mg/L) among the studied sites. Asexpected, because of seasonality, the temperature decreased along with the study. The bacteriological quality of thedrinking water was acceptable for consumption according to the current legislation. No significant correlations werefound between the physicochemical and bacteriological variables and the abundance of fungi (p-value > 0.05). Of thetotal 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 wereconstantly observed in one of the sampled points; meanwhile, the other sites showed a more diverse fungalcommunity during the monthly monitoring. The results showed that fungi are widely found in the DWDS, andchanges in their abundance and diversity can be expected at different sites throughout stagnation periods. Theoccurrence 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.