Submit Manuscript | http://medcraveonline.com Abbreviations: TC, total coliforms; UV, ultraviolet; E. coli, Escherichia coli; DEC, diarrheagenic Escherichia coli; EPEC, enteropathogenic E. coli; ETEC. enterotoxigenic E. coli; STEC, shiga toxin-secreting E. coli; EIEC, enteroinvasive E. coli; EAEC, enteroaggregative E. coli; CFU, colony forming units; SD, standard deviation; PCR, polymerase chain reaction. Introduction For over fve years the state of Chiapas, Mexico, has occupied the frst place of extreme poverty in the country. Its inhabitants have an educational delay, limited access to health care services, social security and to basic household services such as potable water. 1 During 2008, the mortality rate due to diarrhea among chiapanecan children under fve years old was 42.8 deaths per 100 000 live births, more than threefold above the national rate (12.1). 2 Stevens et al., 3 showed that risk factors such as malnutrition, contaminated water, poor sanitation, and indoor air pollution increases child mortality in Southern (16%) Mexico, more than in the Northern region (<2%). 3 Despite the incidence of diarrheal illness as one of the ten leading causes of children mortality and morbidity in Chiapas, 2,3 specifc etiologic agents are not investigated perhaps for a lack of resources. In effort to begin evaluating agents and risk factors implicated in these cases, we recently demonstrate a high prevalence of malnutrition and intestinal parasites among children from marginalized municipalities of Chiapas. 4 The inhabitants of Oxchuc, Chiapas, one of Mexico’s most marginalized municipalities, obtain potable water for household use from natural sources such as rain, wells or rivers. Since open defecation is a common practice among inhabitants of Oxchuc and other marginalized municipalities of Chiapas, water sources are prone to contamination by feces containing bacterial pathogens associated with water-borne diseases. This may account for the documented high mortality rates due to diarrheal diseases in the area. 2,3 In order to improve water quality in resources-limited regions, affordable methods to disinfect water need to be engineered. Water for human consumption must have an appropriate quality in order to prevent and avoid transmission of gastrointestinal pathogens. 5 These systems should demonstrate effectiveness in removing potential human pathogens from water samples such as the presence of E. coli strains, a biological indicator of fecal contamination. Thus, the objective of this study was to evaluate the effcacy of a UV radiation- based water disinfection system, hereafter called Llaveoz, to eliminate total coliforms and pathogenic E. coli strains, in water utilized for human consumption in a rural zone of Chiapas, Mexico. Materials and methods Study zone This study was carried out in the Lelenchij locality, Oxchuc, Chiapas, Mexico, which is located at 1,900 meters above the sea level, in the Altos Tsotsil Tseltal zone. The community had 807 inhabitants in 2013, 99.8% of which do not have access to health care services. Their houses in general have electricity (94.3%) but 99.2% and 86.5% of them do not have sources of potable water and sewage, respectively and 41.4% of households have earthen foor. 6 Llaveoz water disinfection system The Llaveoz™ water disinfection system (patent US2011/0215037 A1) consists in a plastic faucet which is placed at the base of a water container used at home for water storage; the faucet contains an ultraviolet light bulb UVC type which uses electricity (110V or 12V). Its light goes on when the faucet is opened in order to pour J Microbiol Exp. 2014;1(3):100‒105. 100 © 2014 Gutierrez-Jimenez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work non-commercially. Evaluation of a point-of use water purifcation system (Llaveoz) in a rural setting of Chiapas, Mexico Volume 1 Issue 3 - 2014 Javier Gutierrez-Jimenez, Florence Cassassuce, Liliana Martinez-de la Cruz, Jose Alexis De Aquino-Lopez, Juan Antonio Hernandez-Shilon, Maria Adelina Schlie- Guzman, Jorge E Vidal University of Science and Arts of Chiapas, Mexico Correspondence: Javier Gutierrez-Jimenez, University of Science and Arts of Chiapas, Libramiento norte poniente#1150, Col. Lajas Maciel, Tuxtla Gutierrez, Chiapas, Mexico, Tel +52- 9616170440/ 4303, Email Received: May 19, 2014 | Published: June 24, 2014 Abstract Access to potable water is a priority for highly-marginalized rural communities of Chiapas, Mexico where consumption of poorly sanitized water has fostered severe diarrheal diseases among children. Interventions aimed to reduce contaminants present in water are necessary to reduce morbidity and mortality rates. In this work we evaluated the effciency of a point of use water purifcation system, Llaveoz, to eradicate total coliform (TC) bacteria and diarrheagenic E. coli (DEC) strains in 62 paired water samples obtained from households during the dry and rainy season. TC was determined by the membrane fltration method whereas DEC strains were evaluated by a multiplex PCR approach. After Llaveoz treatment, water samples collected during the dry season (N=20) had an 80.3% reduction of TC counts (p<0.05). Similarly, TC were signifcantly reduced (72.3%, (p<0.05)) in water samples treated during the rainy season (N=42). A total of 28 E. coli strains were isolated of which 14.3% (N=4) were identifed as DEC strains (ETEC (N=2), EAEC (N=1) or EIEC (N=1)) in untreated water samples. Llaveoz-treated water did not contain DEC strains. Thus, the Llaveoz system represents an alternative method to obtain more pure water in regions where potable water sources are not available. Keywords: Chiapas, diarrheagenic E. coli, llaveoz, water purifcation system Journal of Microbiology & Experimentation Research Article Open Access