title: Point-of-use Unit Based on Gravity Ultrafiltration Removes Waterborne Gastrointestinal Pathogens from Untreated Water Sources in Rural Communities.
abstract: OBJECTIVE
  In developing countries, rural communities often face the lack of potable water infrastructure and must rely on untreated sources for drinking, which are often contaminated with waterborne pathogens. The use of home water treatment devices is seen as one means of reducing the risk of exposure to waterborne pathogens. The aim of this study was to evaluate the microbiological and physicochemical performance of a simple in-home point-of-use device based on gravity ultrafiltration through an ultrafilter membrane.
  
  
  METHODS
  Twenty-five randomly selected households from 2 rural communities in Culiacán, Mexico, were enrolled. Water samples were collected before and after treatment and during storage for a period of 8 weeks. Heterotrophic bacteria, total coliforms, fecal coliforms, Escherichia coli, and Giardia spp were quantified, as well as various physicochemical parameters.
  
  
  RESULTS
  All of the untreated water samples contained high levels of indicator bacteria, but none were detected in the treated water fulfilling the requirements set by the Mexican Norm (NOM-127-SSA1-1994) and the World Health Organization guidelines for drinking water. However, indicator bacteria (fecal coliforms and E coli) were detected in every sample from water stored 24 hours after treatment.
  
  
  CONCLUSIONS
  This study demonstrated that point-of-use filters using gravity-fed ultrafilters are a low-cost, effective water treatment technology for water of poor microbial quality. However, further identification of the sources and mechanisms by which water is contaminated when stored after treatment will help with designing and implementing better strategies for keeping water safe for domestic use.
authors: Laboratory of Environmental and Food Microbiology, Centro de Investigación en Alimentación y Desarrollo, A.C., Unidad Culiacán, Sinaloa, México (Drs Chaidez, Valdez-Torres, and Castro-del Campo).
authors: Cristóbal
authors: C
authors: Chaidez
authors: Consejo Nacional de Ciencia y Tecnología-Centro de Investigación en Alimentación y Desarrollo, A.C. (Dr. Ibarra-Rodríguez).
authors: Juan R
authors: JR
authors: Ibarra-Rodríguez
authors: Laboratory of Environmental and Food Microbiology, Centro de Investigación en Alimentación y Desarrollo, A.C., Unidad Culiacán, Sinaloa, México (Drs Chaidez, Valdez-Torres, and Castro-del Campo).
authors: José Benigno
authors: JB
authors: Valdez-Torres
authors: Facultad de Ciencias Químico-Biológicas, Universidad Autónoma de Sinaloa, Ciudad Universitaria, Culiacán, Sinaloa, México (Dr Soto).
authors: Marcela
authors: M
authors: Soto
authors: Soil, Water and Environmental Science Department, University of Arizona, Tucson, Arizona (Dr Gerba).
authors: Charles P
authors: CP
authors: Gerba
authors: Laboratory of Environmental and Food Microbiology, Centro de Investigación en Alimentación y Desarrollo, A.C., Unidad Culiacán, Sinaloa, México (Drs Chaidez, Valdez-Torres, and Castro-del Campo). Electronic address: ncastro@ciad.mx.
authors: Nohelia
authors: N
authors: Castro-Del Campo
mesh_terms: D060766:Drinking Water / Q000382:microbiology*; D004755:Enterobacteriaceae; D004867:Equipment Design; D004926:Escherichia coli; D006112:Gravitation; D008800:Mexico; D012424:Rural Population; D014462:Ultrafiltration / Q000295:instrumentation / Q000379:methods*; D014871:Water Microbiology; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D060766:Drinking Water
keywords: Giardia; developing countries; drinking water; fecal bacterial indicators; microbial contamination; water treatment