Enterococci used as complementary indicator of fecal contamination to assess water quality from public schools in the city of Curitiba, Paraná, Brazil

Abstract

The study evaluated the drinking water quality from 45 public schools in the city of Curitiba, Brazil. Water samples were harvested from two different points at each school: the first one, drinking fountain used by students (n=45) and the second, kitchen faucet (n=45), comprising 90 samples. The samples were submitted to analysis according to current legislation, such as: dosage of free chlorine; colony counts of heterotrophic bacteria; presence of total coliform bacteria and Escherichia coli. In addition, an enterococci analysis was also included as a complementary microbiological indicator of fecal contamination. The isolated strains of enterococci were identified and submitted to an antibiotic susceptibility test. In relation to the legal parameters, 35.5% (n=16) of the 45 schools evaluated did not meet the quality water standards set by the Brazilian legislation. Although none of the 90 samples exhibited the presence Escherichia coli, 6.6% (n=6) of the analyzed samples presented enterococci contamination. Regarding the antibiotic susceptibility test, the isolated strains demonstrated a similar behavior, became resistant to six antibiotics and had intermediate sensitivity to one (Streptomycin) of the nine antibiotics tested. The drinking water destined for human consumption in the public schools may pose health risks for students since the fecal contamination by enterococci was confirmed, and it could be observed that the water may be a source of genes from bacteria resistant to antimicrobials. This study reinforces the importance of monitoring complementary microbiological indicators to assure water quality, seeing that fecal contamination was detected only when alternative parameters were inserted, emphasizing the relevance of including microbiological indicators beyond what the legislation requires to evaluate the drinking water more effectively and to safeguard public health.

Parasitological, microbiological, and antimicrobial resistance profiles of raw and drinking water in a tourist city in the tri-border region of South America

“…These results also highlight the importance of inserting at least two FIB to guarantee safe water, a fact also observed by Waideman et al (2020), in which several samples from kitchen faucets and drinking fountains from children's public schools were only considered unsuitable for human consumption when enterococci data contamination was evaluated.…”

“…The facts that there are no data regarding the environmental epidemiology of protozoa in raw and treated water (TW) in Foz do Iguaçu, together with the prevalence data mentioned above, were important motivating factors behind the investigation of drinking water quality in school environments, as this is considered a major public health concern (WHO 2015; Waideman et al 2020). Another important goal of this study was the evaluation of antimicrobial resistance phenomena, focusing on Enterococcus spp., Pseudomonas aeruginosa, and Escherichia coli, and the comparison of the antibiotic resistance profile of the isolated strains in water.…”

Investigation of Microbiological Quality Changes of Roof-Harvested Rainwater Stored in the Tanks

“…The presence of these microorganisms in drinking water is not acceptable, and their detection indicates contamination that may threaten human health. Their presence is noted not only in rainwater or surface water but also, according to some studies, in water subjected to chemical disinfection with chlorine preparations [56]. Therefore, their presence in rainwater and long-term survival in storage tanks (even above 50 jtk/100 mL on day 28 of storage) should not be surprising.…”

Controle de qualidade microbiológica da água para consumo humano no Brasil: revisão sistemática

“…Quando as águas distribuídas chegam ao seu local de destino, faz-se necessário que o controle de qualidade da água continue sendo feito, pois na maioria das vezes água faz um trajeto longo e obscuro até chegar nas torneiras. Em testes de controle microbiológico de água potável feitos em escolas mostram parâmetros irregulares, devido a contaminação por tubulações quebradas ou ligações clandestinas (Waideman et al, 2020).…”