Presence of Pathogens and Indicator Microbes at a Non-Point Source Subtropical Recreational Marine Beach

Abstract

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.Global estimates indicate that each year more than 120 million cases of gastrointestinal disease and 50 million cases of severe respiratory diseases are caused by swimming and bathing in wastewater-polluted coastal waters (42). Swimming-related illness is attributed predominantly to exposure to microbial pathogens, which enter the water through point sources, such as sewage outfalls. Water quality at beaches may also be impacted by non-point sources, such as storm water runoff, sand resuspension, animal fecal inputs, and human bather shedding (8,12,22,47,59).The concentration of indicator microorganisms in a body of recreational water is used to estimate the health risk to bathers. These microbes serve as surrogates for microbial pathogens. Studies show that the U.S. Environmental Protection Agency (EPA)-recommended indicator microbe for marine beaches, enterococci, shows a significant correlation with illness in marine beaches impacted by point source pollution (38,54). However, a similar correlation has not been identifi...

Spatial variability in airborne bacterial communities across land-use types and their relationship to the bacterial communities of potential source environments

“…Future work will need to integrate molecular surveys of airborne communities with atmospheric chemical transport models across more extensive sample sets in order to more confidently determine bacterial sources and map their atmospheric trajectories over extended time periods. However, just as we can use bacterial taxa indicative of animal feces to track fecal contamination of bodies of water (Brownell et al, 2007;Abdelzaher et al, 2010;Wery et al, 2010) or use bacterial communities on the hands of different individuals to identify touched objects , we may be able to use bacterial taxa indicative of possible source environments to identify and compare inputs of bacteria with the atmosphere.…”

Routine screening of harmful microorganisms in beach sands: Implications to public health

“…Numerous studies have shown that beach sand may serve as a reservoir for pathogens harmful to human health and indicator microbes that can be released into surrounding waters through tidal action or run-off (Alm et al, 2003;Whitman and Nevers, 2003;Boehm and Weisberg, 2005;Beversdorf et al, 2007;Colford et al, 2007;Fleisher et al, 2010;Ge et al, 2010;Sinigalliano et al, 2010;Abdelzaher et al, 2010). Several authors have reported that both indicator bacteria and potential pathogens occur in beach sands of both freshwater and marine environments (Sanchez et al, 1986;Ghinsberg et al, 1994Ghinsberg et al, , 1995Obiri-Danso and Jones, 2000;Desmarais et al, 2002;Sato et al, 2005;Vantarakis et al, 2005;Beversdorf et al, 2007;Bonilla et al, 2007;Vogel et al, 2007;Hartz et al, 2008;Abdelzaher et al, 2010).…”

“…Pinto et al (2012) found elevated levels of fecal indicators and parasites in the sand of beaches from São Paulo, Brazil. Abdelzaher et al (2010) found that enterococci in sand beaches of a south Florida, USA beach correlated with supplemental FIB (fecal coliforms, E. coli, and Clostridium perfringens) in both water and sand samples. Pathogens were detected predominantly during the same sampling event that resulted in the highest indicator microbe levels.…”

“…Several authors have reported that both indicator bacteria and potential pathogens occur in beach sands of both freshwater and marine environments (Sanchez et al, 1986;Ghinsberg et al, 1994Ghinsberg et al, , 1995Obiri-Danso and Jones, 2000;Desmarais et al, 2002;Sato et al, 2005;Vantarakis et al, 2005;Beversdorf et al, 2007;Bonilla et al, 2007;Vogel et al, 2007;Hartz et al, 2008;Abdelzaher et al, 2010). In fact, bacterial cell numbers can be substantially higher in the sand than in nearby waters; for example in the Great Lakes region of the US, E. coli in sand can be found at levels of 10 to 100 times higher than adjacent waters, generally ranging from 10 3 to 10 4 CFU/g at an enclosed beach to 10 1.5 to 10 2.5 CFU/g at open beaches (Burton et al, 1987;Doyle et al, 1992;Irvine and Pettibone, 1993;Oshiro and Fujioka, 1995;Whitman and Nevers, 2003;Yamahara et al, 2007).…”

“…Enterococci have been detected in beach sediments where there may not be a clear, nearby source of sewage (Whitman and Nevers, 2003;Shibata et al, 2004;Abdelzaher et al, 2010;Badgley et al, 2010;Wright et al, 2011); sources of enterococci from sewage are relatively easier to identify and control. Harmful bacteria resident in beach sediments can be resuspended in surrounding waters as a result of agitation from recreational activity or storms during the summer season (Abdallah et al, 2005).…”