Freshwater Fish as a Bioindicator for Escherichia coli (E. coli) in Contaminated River Systems in Michigan
Location
Hager-Lubbers Exhibition Hall
Description
Escherichia coli (Migula 1895) (E. coli) contamination in freshwater systems poses a significant public health risk, with sources including wildlife, agricultural runoff, and wastewater discharge. Recent studies suggest that fish may serve as an additional vector for E.coli transmission, yet little research has explored species-specific bacterial retention and potential human exposure. This study investigated (1) whether different fish species accumulate varying concentrations of E. coli, (2) the influence of abiotic and biotic factors on E.coli retention, and (3) the potential for bacterial transfer from fish to humans. Field sampling was conducted in four West Michigan stream systems classified as either impaired (>300 CFU/100mL) or unimpaired (<100 CFU/100mL). Three fish species—Brown Trout (Salmo trutta), Mottled Sculpin (Cottus bairdii), and Creek Chub (Semotilus atromaculatus)—were sampled using electrofishing, and mucus swabs were analyzed using IDEXX Colilert-18™ and Imaging Flow Cytometry (IFCM). Results showed that Creek Chub exhibited significantly higher E.coli concentrations than Brown Trout and Mottled Sculpin (p < 0.05), potentially due to differences in mucus properties. Principal Component Analysis (PCA) indicated that fish size inversely correlated with E.coli load, though abiotic factors such as water temperature and discharge were not significant predictors. Hand swab analysis demonstrated an accumulation of E.coli over consecutive fish handling events, suggesting a potential risk of bacterial transfer to anglers. These findings highlight the need for further investigation into fish as bioindicators of waterborne pathogens and reinforce the importance of hygiene practices in recreational fishing.
Freshwater Fish as a Bioindicator for Escherichia coli (E. coli) in Contaminated River Systems in Michigan
Hager-Lubbers Exhibition Hall
Escherichia coli (Migula 1895) (E. coli) contamination in freshwater systems poses a significant public health risk, with sources including wildlife, agricultural runoff, and wastewater discharge. Recent studies suggest that fish may serve as an additional vector for E.coli transmission, yet little research has explored species-specific bacterial retention and potential human exposure. This study investigated (1) whether different fish species accumulate varying concentrations of E. coli, (2) the influence of abiotic and biotic factors on E.coli retention, and (3) the potential for bacterial transfer from fish to humans. Field sampling was conducted in four West Michigan stream systems classified as either impaired (>300 CFU/100mL) or unimpaired (<100 CFU>/100mL). Three fish species—Brown Trout (Salmo trutta), Mottled Sculpin (Cottus bairdii), and Creek Chub (Semotilus atromaculatus)—were sampled using electrofishing, and mucus swabs were analyzed using IDEXX Colilert-18™ and Imaging Flow Cytometry (IFCM). Results showed that Creek Chub exhibited significantly higher E.coli concentrations than Brown Trout and Mottled Sculpin (p < 0.05), potentially due to differences in mucus properties. Principal Component Analysis (PCA) indicated that fish size inversely correlated with E.coli load, though abiotic factors such as water temperature and discharge were not significant predictors. Hand swab analysis demonstrated an accumulation of E.coli over consecutive fish handling events, suggesting a potential risk of bacterial transfer to anglers. These findings highlight the need for further investigation into fish as bioindicators of waterborne pathogens and reinforce the importance of hygiene practices in recreational fishing.