title: Isolation of bacteriophage host strains of Bacteroides species suitable for tracking sources of animal faecal pollution in water.
abstract: Microbial source tracking (MST) methods allow the identification of specific faecal sources. The aim is to detect the sources of faecal pollution in a water body to allow targeted, efficient and cost-effective remediation efforts in the catchment. Bacteriophages infecting selected host strains of Bacteroides species are used as markers to track faecal contaminants in water. By using a suitable Bacteroides host from a given faecal origin, it is possible to specifically detect bacteriophages of this faecal origin. It can thus be used to detect specific phages of Bacteroides for MST. With this objective, we isolated several Bacteroides strains from pig, cow and poultry faeces by applying a previously optimized methodology used to isolate the host strains from humans. The isolated strains belonged to Bacteroides fragilis and Bacteroides thetaiotaomicron. These strains, like most Bacteroides species, detected phages of the Siphoviridae morphology. Using the newly isolated host strains for phage enumeration in a range of samples, we showed that these detect phages in faecal sources that coincide with their own origin (70-100% of the samples), and show no detection or very low percentages of detection of phages from other animal origins (from 0 to 20% of the samples). Only strains isolated from pig wastewater detected phages in 50% of human sewage samples. Nevertheless, those strains detecting phages from faecal origins other than their own detected fewer phages (2-3 log₁₀ pfu·100 ml⁻¹) than the phages detected by the specific strain of the same origin. On the basis of our results, we propose that faecal source tracking with phages infecting specific Bacteroides host strains is a useful method for MST. In addition, the method presented here is feasible in laboratories equipped with only basic microbiological equipment, it is more rapid and cost-effective than other procedures and it does not require highly qualified staff.
authors: Department of Microbiology, University of Barcelona-Institut de l'aigua, Diagonal 645, E-08028, Barcelona, Spain.
authors: Marta
authors: M
authors: Gómez-Doñate
authors: Andrey
authors: A
authors: Payán
authors: Ivania
authors: I
authors: Cortés
authors: Anicet R
authors: AR
authors: Blanch
authors: Francisco
authors: F
authors: Lucena
authors: Juan
authors: J
authors: Jofre
authors: Maite
authors: M
authors: Muniesa
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000254:growth & development* / Q000302:isolation & purification; D001439:Bacteroides / Q000145:classification / Q000235:genetics / Q000821:virology*; D002417:Cattle; D004784:Environmental Monitoring / Q000379:methods*; D005243:Feces / Q000382:microbiology / Q000821:virology*; D005618:Fresh Water / Q000382:microbiology / Q000821:virology; D011200:Poultry; D012722:Sewage / Q000032:analysis* / Q000382:microbiology / Q000821:virology; D013552:Swine; D014871:Water Microbiology; D014873:Water Pollutants / Q000032:analysis*; D014876:Water Pollution / Q000032:analysis / Q000706:statistics & numerical data*; D014881:Water Supply / Q000032:analysis / Q000706:statistics & numerical data
chemical_list: D012722:Sewage; D014873:Water Pollutants