Percorrer por autor "Weiskerger, Chelsea"
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- Climate Change Impacts on Microbiota in Beach Sand and Water: Looking AheadPublication . Brandão, João; Weiskerger, Chelsea; Valério, Elisabete; Pitkänen, Tarja; Meriläinen, Päivi; Avolio, Lindsay; Heaney, Christopher D.; Sadowsky, Michael J.Beach sand and water have both shown relevance for human health and their microbiology have been the subjects of study for decades. Recently, the World Health Organization recommended that recreational beach sands be added to the matrices monitored for enterococci and Fungi. Global climate change is affecting beach microbial contamination, via changes to conditions like water temperature, sea level, precipitation, and waves. In addition, the world is changing, and humans travel and relocate, often carrying endemic allochthonous microbiota. Coastal areas are amongst the most frequent relocation choices, especially in regions where desertification is taking place. A warmer future will likely require looking beyond the use of traditional water quality indicators to protect human health, in order to guarantee that waterways are safe to use for bathing and recreation. Finally, since sand is a complex matrix, an alternative set of microbial standards is necessary to guarantee that the health of beach users is protected from both sand and water contaminants. We need to plan for the future safer use of beaches by adapting regulations to a climate-changing world.
- Effects of a Changing Earth on Microbial Dynamics and Human Health Risks in the Water/Sand ContinuumPublication . Weiskerger, Chelsea; Brandão, João; Robinson, Clare; Staley, Chris M.; Kleinheinz, Greg; Nshimyimana, Jean Pierre; Kinzelman, Julie; Nevers, Meredith B; Sadowsky, Michael Jay; Phanikumar, Mantha S; Whitman, Richard; Edge, Tom Andrew; Piggot, Alan; Boehm, Alexandria; Aslan, Asli; Badgley, Brian; Heaney, Christopher; Symonds, Erin; Solo-Gabriele, Helena; Fleisher, Jay; Harwood, Jody; Yamahara, Kevan; Vogel, Laura; Jordão, Luisa; Avolio, Lindsay; Merilainen, Paivi; Pitkanen, Tarja; Warish, Ahmed; Staley, Zachery; Klaus, JamesHumans may be exposed to microbial pathogens at recreational beaches via environmental sources such as water and sand. Although infectious disease risk from exposure to waterborne pathogens, and the fecal indicator bacteria (FIB) used to monitor water quality are active areas of research, sand is a relatively unexplored reservoir of pathogens and FIB. Sand and water at beaches experience continuous exchange of microorganisms, and these habitats provide unique advantages and challenges to pathogen introduction, growth, and persistence. Models of FIB and pathogen fate and transport in beach habitats can aid prediction of the risk of infectious disease from recreational water use, but filling knowledge gaps is necessary for accurate modeling. Climate change predictions estimate an increase in global temperatures of 2.5 – 10° F, sea level rise, and intensification of storms and precipitation in some regions. Other global change factors like population growth and urbanization may exacerbate predicted impacts. These changes can alter microbial population dynamics in beach habitats, and may consequently affect the assumptions and relationships used in numerical models. We discuss literature on microbial population and transport dynamics in sand/beach habitats, with an emphasis on how climate change and other anthropogenic influences (e.g., land use, urbanization) should be considered when using and developing models.
- Health risk posed by direct ingestion of yeasts from polluted river waterPublication . Steffen, Heidi Christa; Smith, Katrin; van Deventer, Corné; Weiskerger, Chelsea; Bosch, Caylin; Brandão, João; Wolfaardt, Gideon; Botha, AlfredRiver water is an essential human resource that may be contaminated with hazardous microorganisms. However, the risk of yeast infection through river water exposure is unclear because it is highly dependant on individual susceptibility and has therefore not been well-studied, to date. To evaluate this undefined risk, we analysed the fungal communities in less polluted (LP) and highly polluted (HP) river water, as determined using principal coordinate analysis of pollution indicators. We enumerated culturable yeasts using a thermally selective isolation procedure (37 °C) and thus promoted the growth of potentially opportunistic species. Yeast species identified as clinically relevant were then tested for antifungal resistance. In addition, we propose a quantitative microbial risk assessment (QMRA) framework to quantitatively assess the potential risk of yeast infection. Our results indicated that pollution levels significantly altered fungal communities (p = 0.007) and that genera representing opportunistic and pathogenic members were significantly more abundant in HP waters (p = 0.038). Additionally, the yeast species Candida glabrata and Clavispora lusitaniae positively correlated with other pollution indicators, demonstrating the species' indicator potential. Our QMRA results further indicate that higher risk of infection is associated with increased water pollution levels (considering both physicochemical and bacterial indicators). Furthermore, yeast species with higher pathogenic potential present an increased risk of infection despite lower observed concentrations in the river water. Interestingly, the bloom of Meyerozyma guilliermondii during the wet season suggests that other environmental factors, such as dissolved oxygen levels and water turbulence, might affect growth characteristics of yeasts in river water, which consequently affects the distribution of annual infection risks. The presence of antifungal resistant yeasts, observed in this study, could further contribute to variation in risk distribution. Research on the ecophysiology of yeasts in these environments is therefore necessary to ameliorate the uncertainty and sensitivity of the proposed QMRA model. In addition to the vital knowledge on opportunistic and pathogenic yeast occurrence in river water and their observed association with pollution, this study provides valuable methods and insights to initiate future QMRAs of yeast infections.
- Incorporating Sand Dynamics into Beach Water Quality Science and PolicyPublication . Weiskerger, Chelsea; Brandão, JoãoWater quality monitoring and science at nearshore/beach areas is largely limited to microbial/bacterial contamination of water. However, recent research has found that the sand at beaches can be more contaminated than the water itself. Given that most beachgoers spend more time in the sand than the water, they are potentially exposing themselves to higher concentrations of microbes than previously thought. Dynamic exchange of microbes between water and sand has been observed in marine and freshwater systems across the world. Microbes are often deposited from the water, into the sand at the beach during intermediate wave events. When wave energy is high enough, these accumulated microbes can be washed out of the sand and back into the water in a process deemed resuspension. This is in addition to the microbes in the sand that come from humans, wildlife, and waste materials. Within the sand, microbes can move around via spaces between sand grains and may also form biofilms attached to sand grains. When beachgoers play in the sand or the water, they expose themselves to the bacteria contained in it. This may lead to compromised health conditions, including respiratory, gastroenteric, and ear infections. By focusing monitoring and research efforts on water quality at the expense of sand conditions, we may be unintentionally putting beachgoers in danger with our existing protocols. The good news is, researchers are beginning to understand how sand and water interact to form the microbial community at beaches. Collaborative field and numerical modeling studies have characterized the impacts of sand on beach health, and there has been a shift in scientific focus to the entire beach system, or “beachscape”, rather than just the water. The political realm is also beginning to get involved, with discussions of including sand impacts and dynamics in recreational water guidelines currently underway. The issue of recreational water quality is the epitome of a one health challenge – microbial communities are impacted by human and environmental factors, wildlife usage, and even meteorological conditions. These microbial communities can then feed back to the human system by infecting beachgoers from both the water and the sand. In terms of human health, the paramount goal is to minimize the chance of infection in beachgoers, which will lead to increased visitation at beaches as well as social and economic gains for nearshore areas via tourism. By broadening research foci to the entire beachscape, we can better understand what may make the system dangerous to beachgoers, and we can improve beach management for human, economic, and environmental health. A recurring issue in natural resources is the disconnect between research and policy outcomes. The prospective inclusion of sand as a source of microbial contamination at beaches in future beach health guidelines is a concerted and encouraging attempt to bridge that disconnect. Though policy discussions are ongoing, there is promise that research into sand-water interactions will influence human health, environmental health, and policy outcomes as they relate to marine and nearshore systems.
- Strategies for Monitoring Microbial Life in Beach Sand for Protection of Public HealthPublication . Brandão, João; Valério, Elisabete; Weiskerger, Chelsea; Veríssimo, Cristina; Sarioglou, Konstantina; Novak Babič, Monika; Solo-Gabriele, Helena M.; Sabino, Raquel; Rebelo, Maria TeresaThe 2021 revised guidelines of the World Health Organization recommend monitoring the quality of sand in addition to water at recreational beaches. This review provides background information about the types of beaches, the characteristics of sand, and the microbiological parameters that should be measured. Analytical approaches are described for quantifying fungi and fecal indicator bacteria from beach sand. The review addresses strategies to assess beach sand quality, monitoring approaches, sand remediation, and the proposed way forward for beach sand monitoring programs. In the proposed way forward, recommendations are provided for acceptable levels of fungi given their distribution in the environment. Additional recommendations include evaluating FIB distributions at beaches globally to assess acceptable ranges of FIB levels, similar to those proposed for fungi.