Identification, Comparison, and Profiling of Selected Diarrhoeagenic Pathogens from Diverse Water Sources and Human...

Ingestion of contaminated aqueous resources frequently precipitates severe enteric conditions like dysentery, typhoid fever, and hepatitis, which remain leading causes of morbidity in developing regions. Prior research has shown that the presence of diarrhoeagenic pathogens in municipal and natural supplies poses a persistent global health threat. Traditional surveillance often relies on phenotypic assays that may lack the resolution needed to trace transmission pathways between environmental reservoirs and mammalian hosts during localized outbreaks. Identifying specific virulence factors and antimicrobial resistance markers remains essential for understanding the pathogenicity of circulating bacterial strains. Existing monitoring frameworks frequently overlook the genetic overlap between environmental isolates and clinical specimens, leading to incomplete risk assessments. This absence of evidence motivated a comprehensive genomic investigation into the distribution of enteric bacteria across diverse matrices including wastewater and groundwater.

This investigation identifies and characterizes specific enteric microbes across 3168 environmental and 135 biological samples using high-resolution molecular techniques to establish a baseline for regional water safety. Researchers sought to compare the genetic signatures of pathogens found in wastewater, groundwater, and treated supplies with those from human and animal excreta. The team aimed to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) and other high-risk organisms using advanced whole-genome sequencing (WGS). Mapping the distribution of virulence genes across different water sources provides a clearer picture of potential infection risks for local populations and informs future infrastructure investments. Establishing a link between environmental contamination and faecal shedding helps refine public health interventions and sanitation strategies. The project evaluates the efficacy of current water treatment standards in eliminating resistant bacterial lineages that carry genes like acrA and baeR.

Investigators collected 3168 aqueous specimens from various sources including wastewater and groundwater alongside 135 faecal samples from both human and animal subjects for comparative analysis. Initial screening utilized culture-based techniques to isolate presumptive colonies of Vibrio cholerae, Shiga toxin-producing Escherichia coli, and Escherichia coli O157:H7. Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) mass spectrometry provided rapid proteomic identification of 555 distinct isolates recovered from the samples. Polymerase Chain Reaction (PCR) assays targeted specific virulence determinants to assess the pathogenic potential of the recovered strains before they were subjected to comprehensive genomic analysis. Whole-Genome Sequencing (WGS) enabled high-resolution profiling of the entire genetic complement, allowing for the detection of specific markers like hcp1/tssD1. Bioinformatic pipelines analyzed the sequencing data to detect overlapping resistance markers and virulence factors across wastewater, treated water, and stool specimens.

Whole-Genome Sequencing (WGS) identified STEC as the dominant species, appearing in 92.9% of the analyzed isolates across all sample types, confirming its widespread environmental distribution. Culture-based screening initially suggested high presumptive prevalence for Vibrio cholerae at 37.1% and E. coli O157:H7 at 22.7% in the initial cohort. Proteomic analysis via MALDI-TOF reclassified the Vibrio cholerae isolates specifically as Vibrio albensis, highlighting the necessity of high-precision identification tools. Wastewater samples exhibited the highest STEC prevalence at 60%, while treated water and groundwater showed rates of 54.1% and 36.8% respectively, highlighting the persistence of these microbes. PCR testing detected virulence genes in 46.4% of water isolates and 66% of stool specimens, indicating a high potential for pathogenicity. Genomic profiling revealed thirteen virulence genes and five resistance markers, including acrA and baeR, that overlapped between treated water and faecal samples.

The significant genetic overlap between treated water and faecal isolates indicates that current purification processes may not fully eliminate hazardous diarrhoeagenic pathogens from the municipal supply. These findings suggest that environmental reservoirs serve as central nodes for the dissemination of antimicrobial resistance genes like hlyE and tssD1. Enhanced monitoring protocols must integrate genomic surveillance to accurately assess the public health risks linked to diverse water sources and faecal contamination in urban environments. The presence of virulent STEC strains in groundwater highlights a vulnerability in rural and peri-urban infrastructure that requires immediate attention. Future research should focus on the survival mechanisms of Vibrio albensis within municipal distribution networks to prevent potential outbreaks. Strengthening water quality standards and treatment protocols is imperative to mitigate the transmission of enteric diseases between animals, humans, and the environment.