Complete genome sequence of new bacteriophage phiE142, which causes simultaneously lysis of multidrug-resistant Escherichia coli O157:H7 and Salmonella enterica

Bacterial strains used in the host range spectrum of the bacteriophage phiE142. Phage was assessed for host range by spot testing. (+) indicate positive sensitivity to phage lysis, and (-) indicate negative sensitivity to phage lysis. (DOCX 41 kb

Risk assessment of selected opportunistic pathogens in drinking water.

Water as a route of opportunistic bacterial disease transmission has not been well established. The use of epidemiological evidence linking drinking water bacterial contamination to health effects in a population is lacking and very costly to obtain. Also, the significance of exposure to low-level contamination is difficult to determine epidemiologically. This makes it difficult to estimate the impact on a community. The use of risk assessment approach allows an understanding of low-level exposure; and to define it in a more quantitative fashion. Microbial risk assessment was employed to determine the risks associated with exposure to selected opportunistic bacterial pathogens (Aeromonas hydrophila and Pseudomonas aeruginosa) present in drinking water from various sources. An extensive analysis was conducted on drinking water obtained from various sources including point-of-use (POU)-treated water, tap water with POUconnection, tap water, bottled water, and water from vending machines and storage tanks. Enumerated bacteria included: A. hydrophila, heterotrophic plate count (HPC) bacteria, Mycobacteriuni spp., Plesiomonas shigelloides, P. aeruginosa, and total and fecal coliforms. It was found that opportunistic pathogens were present in small numbers in drinking water. Neither fecal coliforms nor P. shigelloides were found in the drinking water samples. The annual risks of colonization based on the consumption of 2L/day/person for drinking water were determined to be as high as 7.9x10⁻⁵ and 9.9x10⁻⁴ for A. hydrophila and P. aeruginosa, respectively at exposure levels ranging from 90 to 10 CFliimL. respectively. The results obtained indicates that the risk of colonization is a transient process, and the probability of infection may be very but could result in the most vulnerable (very young, the elderly and immunocompromised). More studies are needed on the occurrence of opportunistic pathogens in drinking water from various sources and animal andjor human feeding studies to better define dose-response in both healthy and immunocomprimised individuals. There is no doubt that the greatest need for microbial risk assessment is the occurrence data. Therefore, national surveys in drinking water from various sources will help in the developing of microbial risk assessment for opportunistic bacterial pathogens. The use of conventional methods as well as molecular approaches are recommended in order to obtain a more accurate identification of waterborne bacterial pathogens.hydrology collectio

They'Er Looking Ahead

Photograph used for a story in the Oklahoma Times newspaper. Caption: "Mayor Latting and the Rev. Robert M. Shaw take an advance look at a copy of a book area religious leaders will be distributing April 29.

Isolation and Characterization of phiLLS, a Novel Phage with Potential Biocontrol Agent against Multidrug-Resistant Escherichia coli

Foodborne diseases are a serious and growing problem, and the incidence and prevalence of antimicrobial resistance among foodborne pathogens is reported to have increased. The emergence of antibiotic-resistant bacterial strains demands novel strategies to counteract this epidemic. In this regard, lytic bacteriophages have reemerged as an alternative for the control of pathogenic bacteria. However, the effective use of phages relies on appropriate biological and genomic characterization. In this study, we present the isolation and characterization of a novel bacteriophage named phiLLS, which has shown strong lytic activity against generic and multidrug-resistant Escherichia coli strains. Transmission electron microscopy of phiLLS morphology revealed that it belongs to the Siphoviridae family. Furthermore, this phage exhibited a relatively large burst size of 176 plaque-forming units per infected cell. Phage phiLLS significantly reduced the growth of E. coli under laboratory conditions. Analyses of restriction profiles showed the presence of submolar fragments, confirming that phiLLS is a pac-type phage. Phylogenetic analysis based on the amino acid sequence of large terminase subunits confirmed that this phage uses a headful packaging strategy to package their genome. Genomic sequencing and bioinformatic analysis showed that phiLLS is a novel bacteriophage that is most closely related to T5-like phages. In silico analysis indicated that the phiLLS genome consists of 107,263 bp (39.0 % GC content) encoding 160 putative ORFs, 16 tRNAs, several potential promoters and transcriptional terminators. Genome analysis suggests that the phage phiLLS is strictly lytic without carrying genes associated with virulence factors and/or potential immunoreactive allergen proteins. The bacteriophage isolated in this study has shown promising results in the biocontrol of bacterial growth under in vitro conditions, suggesting that it may prove useful as an alternative agent for the control of foodborne pathogens. However, further oral toxicity testing is needed to ensure the safety of phage use

PERFORMANCE OF A SURFACE FLOW CONSTRUCTED WETLAND SYSTEM USED TO TREAT SECONDARY EFFLUENT AND FILTER BACKWASH WATER

  The performance of a surface flow wetland system used to treat activated sludge effluent and filter backwash water from a tertiary treatment facility was evaluated. Samples were collected before and after vegetation removal from the system which consists of two densely vegetated settling basins (0.35 ha), an artificial stream, and a 3-ha surface flow wetland. Bulrush (Scripus spp.) and cattail (Typha domingensis) were the dominant plant species. The average inflow of chlorinated secondary effluent during the first two months of the actual study was 1.9  m3 min-1 while the inflow for backwash water treatment ranged from 0.21 to 0.42 m3 min-1. The system was able to reduce TSS and BOD5 to tertiary effluent standards; however, monitoring of chloride concentrations revealed that wetland evapotranspiration is probably enriching pollutant concentrations in the wetland outflow. Coliphage removal from the filter backwash was 97 and 35% during 1999 and 2000, respectively. However, when secondary effluent entered the system, coliphage removal averaged 65%. After vegetation removal, pH and coliphage density increased significantly (