Vertical stratification of the water microbiome in an electric water heater tank: implications for premise plumbing opportunistic pathogens.

Hot water systems are the most frequent environment associated with the prevalence and growth of opportunistic premise plumbing pathogens (OPPPs). Previous studies identified water heaters as a source of waterborne diseases and concluded that design variables may contribute to their prevalence. A multifaceted approach was used to investigate the vertical stratification of the microbiome and selected OPPPs in an electric water heater tank connected to a home plumbing system simulator.

Potassium ferrate's disinfecting ability: a study on human adenovirus, , and microbial indicators under varying pH and water temperature conditions.

Ferrate (Fe(VI): HFeO /FeO), a potent oxidant, has been investigated as an alternative chemical disinfectant in water treatment due to its reduced production of disinfection by-products. In this study, we assessed the disinfecting ability of potassium ferrate against a variety of microorganisms, including waterborne pathogens, under varying pH and water temperature conditions. We presented CT values, a metric of ferrate concentrations (C) and contact time (T), to quantify microbial inactivation rates.

Assessing residential activity in a home plumbing system simulator: monitoring the occurrence and relationship of major opportunistic pathogens and phagocytic amoebas.

Opportunistic premise plumbing pathogens (OPPPs) have been detected in buildings' plumbing systems causing waterborne disease outbreaks in the United States. In this study, we monitored the occurrence of OPPPs along with free-living amoeba (FLA) and investigated the effects of residential activities in a simulated home plumbing system (HPS). Water samples were collected from various locations in the HPS and analyzed for three major OPPPs: , nontuberculous mycobacterial species (e.

Inactivation efficacy and mechanisms of wavelength-specific UV sources for various strains of Legionella pneumophila serogroup 1.

Infections of Legionnaires' disease in the United States caused by Legionella have increased ninefold between the years 2000-2018. Legionella harbored in biofilms or inside amoeba within premise plumbing can be more resistant to disinfectants, thus causing treatment challenges. Ultraviolet-light emitting diodes (UV-LEDs) are an emerging water disinfection technology with several advantages over conventional UV lamps.

A comparison of methods to detect low levels of Salmonella enterica in surface waters to support antimicrobial resistance surveillance efforts performed in multiple laboratories.

Developing effective and sensitive detection methods for antimicrobial resistant Salmonella enterica from surface water is a goal of the National Antimicrobial Resistance Monitoring System (NARMS). There are no specified methods for recovery of S. enterica in surface waters in the U.

Ciprofloxacin- and azithromycin-resistant bacteria in a wastewater treatment plant.

The occurrence of antibiotic-resistant bacteria (ARB) in wastewater treatment plants (WWTPs) has become an occupational and environmental concern. WWTPs are engineered systems that treat wastewater to meet public health standards before release into the environment. The residuals, as either effluent or solids, are then discharged or beneficially recycled into the environment.

Understanding Microbial Loads in Wastewater Treatment Works as Source Water for Water Reuse.

Facing challenges in water demands and population size, particularly in the water-scarce regions in the United States, the reuse of treated municipal wastewater has become a viable potential to relieve the ever-increasing demands of providing water for (non-)potable use. The objectives of this study were to assess microbial quality of reclaimed water and to investigate treatability of microorganisms during different treatment processes. Raw and final treated effluent samples from three participating utilities were collected monthly for 16 months and analyzed for various microbial pathogens and fecal indicator organisms.

Comparison of two culture methods for the enumeration of Legionella pneumophila from potable water samples.

Legionella infections have steadily increased in the United States over the last 20 years, and most of these infections have been attributed to contaminated water. The gold standard for confirmation of Legionella presence in water is culturing with Buffered Charcoal Yeast Extract (BCYE) agar. Following many modifications, this method is still time-consuming, expensive, and can take longer than 10 days for full confirmation.

Closed Genome and Plasmid Sequences of Legionella pneumophila AW-13-4, Isolated from a Hot Water Loop System of a Large Occupational Building.

Unused water in unoccupied buildings can become stagnant, with reductions in temperature and levels of disinfectant resulting in increased microbial growth. We report the closed and complete genome and plasmid of strain AW-13-4 (serogroup 1), which was isolated from a hot water loop system of a large building.

Legionellosis and Recent Advances in Technologies for Control in Premise Plumbing Systems: A Review.

This review discusses , among the most prolific and publicly well-known waterborne pathogens, and advances in potential treatment technologies. The number of cases associated with continues to rise, as does its public awareness. Currently, cases associated with premise plumbing account for the largest number of legionellosis cases in the United States.

Efficacy of inactivation of human enteroviruses by dual-wavelength germicidal ultraviolet (UV-C) light emitting diodes (LEDs).

The efficacy of germicidal ultraviolet (UV-C) light emitting diodes (LEDs) was evaluated for inactivating human enteroviruses included on the United States Environmental Protection Agency (EPA)'s Contaminant Candidate List (CCL). A UV-C LED device, emitting at peaks of 260 nm and 280 nm and the combination of 260∣280 nm together, was used to measure and compare potential synergistic effects of dual wavelengths for disinfecting viral organisms. The 260 nm LED proved to be the most effective at inactivating the CCL enteroviruses tested.

Draft Genome Sequences of Seven Legionella pneumophila Isolates from a Hot Water System of a Large Building.

Public health data show that a significant fraction of the nation's waterborne disease outbreaks are attributable to premise plumbing. We report the draft genome sequences of seven serogroup 1 isolates from hot water lines of a large building. Genomic analysis identified the isolates as belonging to sequence type 1.

Survey of US wastewater for carbapenem-resistant Enterobacteriaceae.

A survey for antibiotic-resistant (AR) Escherichia coli in wastewater was undertaken by collecting samples from primary clarifiers and secondary effluents from seven geographically dispersed US wastewater treatment plants (WWTPs). Samples were collected at each WWTP in cool and summer months and cultured using selective media. The resulting isolates were characterized for resistance to imipenem, ciprofloxacin, cefotaxime, and ceftazidime, presence of carbapenemase and extended-spectrum beta-lactamase (ESBL) genes, and phylogroups and sequence types (STs).

Applicability of integrated cell culture reverse transcriptase quantitative PCR (ICC-RTqPCR) for the simultaneous detection of the four human enteric enterovirus species in disinfection studies.

A newly developed integrated cell culture reverse transcriptase quantitative PCR (ICC-RTqPCR) method and its applicability in UV disinfection studies is described. This method utilizes a cell culture system coupled with four RTqPCR assays to detect four species of human enterovirus (e.g.

Evaluating UV-C LED disinfection performance and investigating potential dual-wavelength synergy.

A dual-wavelength UV-C LED unit, emitting at peaks of 260 nm, 280 nm, and the combination of 260|280 nm together was evaluated for its inactivation efficacy and energy efficiency at disinfecting Escherichia coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores, compared to conventional low-pressure and medium-pressure UV mercury vapor lamps. The dual-wavelength unit was also used to measure potential synergistic effects of multiple wavelengths on bacterial and viral inactivation and DNA and RNA damage. All five UV sources demonstrated similar inactivation of E.

Applicability of UV resistant Bacillus pumilus endospores as a human adenovirus surrogate for evaluating the effectiveness of virus inactivation in low-pressure UV treatment systems.

Recent studies have demonstrated the potential to use Bacillus pumilus endospores as a surrogate for human adenovirus (HAdV) in UV disinfection studies. The use of endospores has been limited by observations of batch-to-batch variation in UV sensitivity. This study reports on a propagation method that utilizes a commercially available medium to produce UV tolerant B.

Determining pathogen and indicator levels in class B municipal organic residuals used for land application.

Biosolids are nutrient-rich organic residuals that are currently used to amend soils for food production. Treatment requirements to inactivate pathogens for production of Class A biosolids are energy intensive. One less energy intensive alternative is to treat biosolids to Class B standards, but it could result in higher pathogen loads.

Development of a sensitive detection method for stressed E. coli O157:H7 in source and finished drinking water by culture-qPCR.

A sensitive and specific method that also demonstrates viability is of interest for detection of E. coli O157:H7 in drinking water. A combination of culture and qPCR was investigated.

Chlorine disinfection of blended municipal wastewater effluents.

Blending is used in the wastewater industry to manage wet-weather events. Wastewater is treated through primary clarification, with flows in excess of the hydraulic capacity of the secondary system being directed to effluent disinfection. Before disinfection, the primary clarified effluent is "blended" with effluents that have been treated through the secondary system.

Occurrence of antibiotic-resistant uropathogenic Escherichia coli clonal group A in wastewater effluents.

Isolates of Escherichia coli belonging to clonal group A (CGA), a recently described disseminated cause of drug-resistant urinary tract infections in humans, were present in four of seven sewage effluents collected from geographically dispersed areas of the United States. All 15 CGA isolates (1% of the 1,484 isolates analyzed) exhibited resistance to trimethoprim-sulfamethoxazole (TMP-SMZ), accounting for 19.5% of the 77 TMP-SMZ-resistant isolates.

The widespread occurrence of the enterohemolysin gene ehlyA among environmental strains of Escherichia coli.

The putative virulence factor enterohemolysin, encoded by the ehlyA gene, has been closely associated with the pathogenic enterohemorrhagic Escherichia coli (EHEC) group. Escherichia coli isolates from effluents from seven geographically dispersed municipal wastewater treatment plants were screened for the presence of enterohemolysin. A total of 338 E.

Detection of intrinsic vancomycin resistant enterococci in animal and human feces.

Fecal samples from animal species and humans were analyzed by quantitative culture for enterococci and vancomycin resistant enterococci (VRE). Each host species carried enterococci which exhibited intrinsic intermediate resistance to vancomycin and sensitivity to teicoplanin (Van C phenotype). The carriage rate in humans was 9%.