Exploring links between water quality and E. coli O157:H7 survival potential in well waters from a rural area of southern Changchun City, China

Abstract

Waterborne infectious disease outbreak associated with well water contamination is a worldwide public health issue, especially for rural areas in developing countries. In the current study, we characterized 20 well water samples collected from a rural area of southern Changchun city, China, and investigated the survival potential of Escherichia coli O157:H7 in those water samples. The results showed that nitrate and ammonia concentrations in some well water samples exceed the corresponding China drinking water standards, indicating potential contamination by local agricultural farms. Our results also revealed that the average survival time (ttd) of E. coli O157:H7 in all well water samples was 30.09 days, with shortest and longest ttd being 17.95 and 58.10 days, respectively. The ttds were significantly correlated with pH and the ratio of total nitrogen to total phosphorus. In addition, it was found that the shape parameter (p) and first decimal reduction parameter (δ) were negatively (P < 0.05) and positively (P < 0.05) correlated to ttd, respectively. Our study showed that E. coli O157:H7 could survive up to two months in well water, suggesting that this pathogen could constitute a great public health risk.

Persistence of Salmonella Typhimurium in Well Waters from a Rural Area of Changchun City, China

“…In the current study, it was found that the first log reduction time ( δ ) was significantly ( p < 0.05) correlated with ttd s. This is well in line with our previous report showing that δ was positively related with ttd of E. coli O157:H7 in well waters, as well as in agricultural soils [ 15 , 41 ]. Since δ is easier to be obtained, it could be an alternative indicator of the E. coli strains that survived in soils.…”

“…A total of 15 wells were sampled, among them 2 were covered open wells, and the rest were tube wells. For open well sampling, grab sampling technique was used; for tube well sampling, water was sampled only after the existing water in the tube was completely replaced by a large volume of fresh water [ 15 ]. All samples were collected in the morning, when maximum water usage was reached for the local community [ 15 ].…”

Interaction between Fungal Communities, Soil Properties, and the Survival of Invading E. coli O157:H7 in Soils

“…The stock EcO157 EDL931 (ATCC 35150) from−80 • C freezer was inoculated onto a fresh LB (Luria-Bertani) agar plate and incubated at 37 • C for 14-16 h [39]. A single colonywas picked up and inoculated on a solid medium containing two antibiotics (nalidixic acid 20 mg/L and rifampicin 100 mg/L) at 37 • C for 14-16 h. A single colony was selected to grow to a larger volume in LB medium; then, the cells were washed twice using 0.9% NaCl solution and resuspended in deionized water to reach OD 600nm = 1.0 for inoculation into the soilsamples.EcO157 cells were added into soils to a final density of about 0.5 × 10 7 CFU per gram soil (gdw −1 ), and the moisture content of all the soil was adjusted to 60% of water holding capacity (WHC) using sterile deionized water.…”

Qualidade microbiológica e perfil de sensibilidade a antimicrobianos em águas de poços artesianos em um município do noroeste do Rio Grande do Sul

“…Os principais sintomas clínicos causados pela infecção da E. coli enteropatogênica são a diarreia aquosa e a colite hemorrágica, que podem evoluir para a síndrome hemolítico-urêmica, pondo em risco a vida dos seres humanos e animais (SAXENA; KAUSHIK; MOHAN, 2015;INVIK et al, 2017). Esse patógeno tem transmissão fecal-oral e, uma vez no ambiente, pode se espalhar com a água da chuva, em fossas sépticas e excretas de animais expostas a céu aberto, alimentos mal higienizados e águas não tratadas (DING et al, 2018), como verificado no presente estudo. Portanto, esse microrganismo é uma ameaça ao meio ambiente e à saúde pública.…”

“…A transmissão de doenças por água contaminada no meio rural é alta, pois, geralmente, esses locais são mais desassistidos quanto à atuação da Vigilância Sanitária local. Além disso, um dos principais microrganismos responsáveis por infecções gastrointestinais, facilmente transmitido pela água não tratada, é a Escherichia coli enteropatogênica, podendo ter sua origem em fossas e pastagens (DANELUZ; TESSARO, 2015; RÍOS-TOBÓN; AGUDELO-CADAVID; GUTIÉRREZ-BUILES, 2017;SCOTT;LEH;HAGGARD, 2017;DING et al, 2018). A água que abastece essas localidades frequentemente advém de poços comunitários, os quais normalmente não recebem qualquer tipo de tratamento prévio, necessitando de monitoramento dos parâmetros qualidade, conforme estabelecido no capítulo V da Portaria de Consolidação nº 5, de 28 de setembro de 2017 (BRASIL, 2017;COELHO et al, 2017).…”