New and improved methods for F+ coliphage culture, detection, and typing to monitor water and shellfish for fecal contamination Public Deposited

Downloadable Content

Download PDF
Last Modified
  • March 21, 2019
  • Love, David Clifford
    • Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
  • Human fecal contamination of coastal recreational water and in shellfishing water is a public health concern because of disease risks to bathers and shellfish consumers, and resulting economic costs of illnesses and beach or shellfishing closures. Coastal managers monitor water and shellfish quality using microbial fecal indicators. In this study, six such indicator microbes (F+ and somatic coliphages, enterococci, fecal coliforms, E. coli, and Clostridium perfringens) were evaluated and compared in estuarine water and shellfish from nine United States estuaries. Bacterial indicator methods and three F+ or somatic coliphage methods detected significantly more microbes in water at human-impacted stations than at non-human impacted or pristine stations. In shellfish, fecal coliform levels were not predictive of human fecal impacts (p=0.183), unlike E. coli (p=0.023). F+ coliphages were nearly significant in predicting human fecal impacts in shellfish (p =0.073), and were detected in 66% of shellfish samples, using the two-step enrichment assay, the most sensitive F+ coliphage method for both water and shellfish. Genogrouping of F+ RNA isolates found 85.4% (n=877) group I, 11.4% (n=117) group II, 3.4% (n=31) group III, and 0.2% (n=2) group IV isolates in water and shellfish for microbial source tracking. The F+ RNA genotyping rates among estuaries ranged from 96.6% to 100%. This information on the occurrence, levels, types, sources of microbial indicators and on the performance of methods informs the design of human health effects studies on marine bathing waters and choices of fecal indicators for management decisions. Simple, rapid and reliable fecal indicator tests are needed to better monitor and manage waters and wastes. This study developed, optimized, and validated a coliphage culture latex agglutination and typing (CLAT) assay to detect individual F+ coliphage serogroups. CLAT had a sensitivity of 96.4% (185/192 samples) and 98.2% (161/164 samples), and a specificity of 100% (34/34 samples) and 97.7% (129/132 samples) for F+ RNA and F+ DNA coliphages, respectively. This particle agglutination technique for rapid and simple detection and grouping of F+ coliphages provides a new and improved tool to monitor the microbiological quality of drinking, recreational, shellfishing, and other waters.
Date of publication
Resource type
Rights statement
  • In Copyright
  • Sobsey, Mark
Degree granting institution
  • University of North Carolina at Chapel Hill
  • Open access

This work has no parents.