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Swimming in ocean water, including ocean water at beaches not impacted by known point sources of pollution, is an increasing health concern. This study was an initial evaluation of the presence of indicator microbes and pathogens and the association among the indicator microbes, pathogens, and environmental conditions at a subtropical, recreational marine beach in south Florida impacted by non-point sources of pollution. Twelve water and eight sand samples were collected during four sampling events at high or low tide under elevated or reduced solar insolation conditions. The analyses performed included analyses of fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli, enterococci, and Clostridium perfringens), human-associated microbial source tracking (MST) markers (human polyomaviruses [HPyVs] and Enterococcus faecium esp gene), and pathogens (Vibrio vulnificus, Staphylococcus aureus, enterovirus, norovirus, hepatitis A virus, Cryptosporidium spp., and Giardia spp.). The enterococcus concentrations in water and sand determined by quantitative PCR were greater than the concentrations determined by membrane filtration measurement. The FIB concentrations in water were below the recreational water quality standards for three of the four sampling events, when pathogens and MST markers were also generally undetectable. The FIB levels exceeded regulatory guidelines during one event, and this was accompanied by detection of HPyVs and pathogens, including detection of the autochthonous bacterium V. vulnificus in sand and water, detection of the allochthonous protozoans Giardia spp. in water, and detection of Cryptosporidium spp. in sand samples. The elevated microbial levels were detected at high tide and under low-solar-insolation conditions. Additional sampling should be conducted to further explore the relationships between tidal and solar insolation conditions and between indicator microbes and pathogens in subtropical recreational marine waters impacted by non-point source pollution.

Fecal contamination has been a leading problem associated with the impairment of surface waters in the State of Michigan. However, the source of the contamination and the possible presence of pathogens has not been adequately addressed. In this preliminary study, nine major rivers located in the Lower Peninsula of Michigan were investigated for the presence of fecal coliforms, Escherichia coli, enterococci, coliphage, and enteric viruses. Five sites (56%) exceeded the allowable limits set for recreational waters based on E. coli concentrations for the State of Michigan. Three (33%) of these sites (Grand, Kalamazoo, and Rouge rivers) tested positive for the presence of viable enteric viruses. The presence of enteric viruses and elevated levels of microbial indicators suggest that these waters may pose a threat to the health of individuals using them for recreational activities. Several new genotypic and phenotypic characterization methods have emerged that have the ability to define human and animal sources of fecal indicators. Previously, we developed a host-associated molecular marker for Enterococcus faecium, which is human specific and targets the sequence for the enterococcal surface protein (esp). When the nine rivers were screened for the marker, two (Grand and Rouge rivers) were found to be positive, implying the presence of human fecal contamination. This study suggests a preliminary approach for validating the use of molecular markers for identifying sources of fecal pollution in the Great Lakes Region and the human health risks associated with pathogenic viruses. [ABSTRACT FROM AUTHOR]

Current virus-recovery procedures using negatively charged microporous filters provide an inexpensive, reliable method for the recovery and detection of enteroviruses from water and wastewater; however, adjustment of the test samples to pH 3.5 to promote enterovirus adsorption results in significant inactivation of bacteriophage and an inability to simultaneously recover them from large volumes of water using this procedure. Procedures specifically designed for the detection of bacteriophage are currently in use but generally are only effective for small volumes of water. Positively charged filters can be used to recover both enteroviruses and bacteriophage from large volumes of water at neutral pH; however, the filters are expensive. The addition of manganese chloride to test solutions at pH 3.5 prior to filtration through negatively charged Filterite[sup ®] filters allowed for sampling of larger volumes of water by reducing the inactivation of bacteriophage and increasing the recovery of PRD1, MS2, and naturally isolated bacteriophage by a factor of four or five when compared with recoveries from solutions without MnCl[sub 2] . This method provides an inexpensive, reliable alternative to large-volume bacteriophage recovery procedures that use positively charged filters at neutral pH.Key words: bacteriophage, water, recovery, microporous filters.Les méthodes courantes d'isolement des virus utilisant des filtres microporeux à charge négative demeurent une façon peu coûteuse et fiable pour détecter et isoler les entérovirus dans l'eau et dans les eaux usées. Par contre, pour augmenter l'adsorption des entérovirus, il faut ajuster à 3,5 le pH de l'échantillon à tester, ce qui entraîne une inactivation significative des bactériophages et il devient impossible d'isoler simultanément ces deux groupes de virus dans des gros volumes d'eau en utilisant cette méthode. Il existe actuellement des méthodes spécifiquement adaptées pour la détection des bactériophages mais règle générale, elles sont efficaces seulement avec des faibles volumes d'eau. Il est possible d'utiliser des filtres chargés positivement pour isoler simultanément les entérovirus et les bactériophages à partir de gros volumes d'eau à pH neutre mais, par contre, les filtres sont dispendieux. L'addition de chlorure de manganèse dans les échantillons ajustés à pH 3,5 avant la filtration avec des filtres Filterite[sup ®] chargés négativement a permis de traiter adéquatement des plus gros volumes d'eau en diminuant l'inactivation des bactériophages et en augmentant l'isolement de PRD1, MS2 et des bactériophages isolés naturellement par un facteur de 4 à 5 comparativement à la récupération de ces virus dans les échantillons ne contenant pas de MnCl[sub 2] . Cette méthode représente une alternative peu coûteuse et fiable comparativement aux méthodes suggérées utilisant des filtres à charge positive à pH neutre pour isoler des phages dans des gros volumes d'eau.Mots clés : bactériophage, l'eau, récupération, filtres microporeux.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Investigates the direct and indirect effects of mono-, di-, and trivalent salts on the adsorption of several viruses to microporous filters at different pH values. Enhanced adsorption of viruses due to indirect effects; Reduction in the pH of the water due to the salts.