Comparison of methods for the detection of coliphages in recreational water at two California, United States beaches

Abstract

Methods for detection of two fecal indicator viruses, F+ and somatic coliphages, were evaluated for application to recreational marine water. Marine water samples were collected during the summer of 2007 in Southern California, United States from transects along Avalon Beach (n=186 samples) and Doheny Beach (n=101 samples). Coliphage detection methods included EPA method 1601 - two-step enrichment (ENR), EPA method 1602 - single agar layer (SAL), and variations of ENR. Variations included comparison of two incubation times (overnight and 5-h incubation) and two final detection steps (lysis zone assay and a rapid latex agglutination assay). A greater number of samples were positive for somatic and F+ coliphages by ENR than by SAL (p<0.01). The standard ENR with overnight incubation and detection by lysis zone assay was the most sensitive method for the detection of F+ and somatic coliphages from marine water, although the method takes up to three days to obtain results. A rapid 5-h enrichment version of ENR also performed well, with more positive samples than SAL, and could be performed in roughly 24h. Latex agglutination-based detection methods require the least amount of time to perform, although the sensitivity was less than lysis zone-based detection methods. Rapid culture-based enrichment of coliphages in marine water may be possible by further optimizing culture-based methods for saline water conditions to generate higher viral titers than currently available, as well as increasing the sensitivity of latex agglutination detection methods.

Norovirus and human adenovirus occurrence and diversity in recreational water in a karst aquifer in the Yucatan Peninsula, Mexico

“…In Mexico, viruses are not considered in water quality regulations, although elsewhere, somatic and male F+ specific coliphages have been exploited effectively as potential viral indicators of faecal contamination in a variety of aquatic environments (U.S. EPA ; Jofre et al ). Despite the value of such tests, methods for recovering and detecting coliphages can be influenced by several variables, including the efficiency with which the pathogen can be concentrated from different types and volumes of water sampled (Contreras‐Coll et al ; Rodríguez et al ), raising the necessity to determine the efficiency of these methods for different water environments. Previous studies have shown that double layer assay methods together with very low water volumes (10 ml) were used successfully to enumerate somatic and male F+ specific coliphages in groundwater samples from the YP karst aquifer.…”

Application of bacteriophage MS2 in preliminary simulation of inactivation rate of pathogenic viruses in commercial beef and chicken packaging

“…First, the bacteria were cultured on a Tryptone Soya Agar (TSA) culture medium containing ampicillin and streptomycin antibiotics and incubated at 37 °C overnight. A colony was then taken from the culture medium and inoculation in a Tryptone Soya Broth (TSB) containing the antibiotics above until it reached 0.1–0.5 optical density at 600 nm wavelength at 37 °C (Rodríguez et al ., 2012).…”

Development of monitoring tools based on electrical impedance spectroscopy for water treatment and integrated process for wastewater recovery

“…In order to ensure that water sources are not contaminated or polluted, fecal indicator bacteria or viruses, for example coliphages and Bacteriodes fragilis phages are being monitored when the analysis of water samples of public health concern is carried out (Rodríguez et al, 2012). Point source contamination is revealed when there is presence of fecal indicator bacteria or viruses.…”

“…The presence of coliphages has been used for the correlation of fecal contamination and this is particularly advantageous because it serves as a complementary method to bacterial indicators. In particular, the enumeration of coliphages appears to be much simpler (Leclerc et al, 2000;Rodríguez et al, 2012).…”

“…To ensure that water sources are free from microbial pollutants or contamination, fecal indicator bacteria or phages (e.g. coliphages and Bacteriodes fragilis phages) are typically monitored when analyzing water samples for microorganisms of public health concern (Rodríguez et al, 2012). The presence of fecal indicator bacteria or viruses reflects the presence of point-source contamination or fecal contamination.…”