scholarly journals Persistence and Differential Survival of Fecal Indicator Bacteria in Subtropical Waters and Sediments

2005 ◽  
Vol 71 (6) ◽  
pp. 3041-3048 ◽  
Author(s):  
Kimberly L. Anderson ◽  
John E. Whitlock ◽  
Valerie J. Harwood

ABSTRACT Fecal coliforms and enterococci are indicator organisms used worldwide to monitor water quality. These bacteria are used in microbial source tracking (MST) studies, which attempt to assess the contribution of various host species to fecal pollution in water. Ideally, all strains of a given indicator organism (IO) would experience equal persistence (maintenance of culturable populations) in water; however, some strains may have comparatively extended persistence outside the host, while others may persist very poorly in environmental waters. Assessment of the relative contribution of host species to fecal pollution would be confounded by differential persistence of strains. Here, freshwater and saltwater mesocosms, including sediments, were inoculated with dog feces, sewage, or contaminated soil and were incubated under conditions that included natural stressors such as microbial predators, radiation, and temperature fluctuations. Persistence of IOs was measured by decay rates (change in culturable counts over time). Decay rates were influenced by IO, inoculum, water type, sediment versus water column location, and Escherichia coli strain. Fecal coliform decay rates were significantly lower than those of enterococci in freshwater but were not significantly different in saltwater. IO persistence according to mesocosm treatment followed the trend: contaminated soil > wastewater > dog feces. E. coli ribotyping demonstrated that certain strains were more persistent than others in freshwater mesocosms, and the distribution of ribotypes sampled from mesocosm waters was dissimilar from the distribution in fecal material. These results have implications for the accuracy of MST methods, modeling of microbial populations in water, and efficacy of regulatory standards for protection of water quality.

2013 ◽  
Vol 76 (6) ◽  
pp. 967-974 ◽  
Author(s):  
DONNA M. PAHL ◽  
ADRIANA TELIAS ◽  
MICHAEL NEWELL ◽  
ANDREA R. OTTESEN ◽  
CHRISTOPHER S. WALSH

Consumption of fresh tomatoes (Solanum lycopersicum) has been implicated as the cause of several foodborne illness outbreaks in the United States, most notably in cases of salmonellosis. How the levels of fecal indicator organisms (FIOs) in water relate to the counts of these microorganisms on the tomato fruit surface is unknown, although microbial water quality standards exist for agricultural use. This study utilized four types of FIOs currently and historically used in microbial water quality standards (Enterobacteriaceae, total coliforms, fecal coliforms, and Escherichia coli) to monitor the water quality of two surface ponds and a groundwater source. The groundwater tested contained significantly lower counts of all FIOs than the two surface water sources (P < 0.05). Considerable variability in bacterial counts was found in the surface water sources over the course of the season, perhaps explained by environmental variables, such as water temperature, pH, precipitation, and air temperature (R2 of 0.13 to 0.27). We also monitored the fruit surface of grape tomatoes treated with overhead applications of the different water sources over the 2009 and 2010 growing seasons. The type of water source and time of year significantly affected the populations of FIOs in irrigation water (P < 0.05). Despite up to 5-log differences in fecal coliforms and 3-log differences in E. coli between the water sources, there was little difference in the populations measured in washes taken from tomato fruits. This lack of association between the aforementioned FIOs present in the water samples and on the tomato fruit surface demonstrates the difficulty in developing reliable metrics needed for testing of agricultural water to ensure the effectiveness of food safety programs.


2006 ◽  
Vol 4 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Sylvie Seurinck ◽  
Martin Verdievel ◽  
Willy Verstraete ◽  
Steven D. Siciliano

From April to June 2001, a monitoring study at Oostende (Belgium) was conducted to obtain an insight into fecal pollution impairing water quality at this coastal area. Eight sampling sites were selected based on the historically low water quality at these sites compared to the remainder of the area. Indicator organisms such as fecal coliforms, Escherichia coli and fecal streptococci were monitored by plating. A real-time PCR assay for quantification of the human-specific HF183 Bacteroides 16S rRNA genetic marker was used to detect human fecal pollution at the sampling sites. Human fecal pollution was detected at all sampling sites. However, the frequency of detection ranged from 30–100% and the amount of human-specific Bacteroides markers recorded varied between the sampling sites. Concentrations of 107 human-specific Bacteroides markers per l to levels below the detection limit of the real-time PCR assay were recorded. Our results indicate that human fecal pollution is a re-occurring problem in certain areas. Of all the environmental parameters monitored during the study, only rainfall was strongly related to the detection of the indicator organisms and the human-specific Bacteroides marker.


1993 ◽  
Vol 27 (7-8) ◽  
pp. 287-294 ◽  
Author(s):  
S. Lerman ◽  
O. Lev ◽  
A. Adin ◽  
E. Katzenelson

The Israel Ministry of Health is now revising its regulations for the assurance of safe water quality in public swimming pools. Since it is not possible to monitor each of the pathogenic microorganisms, it is often recommended to monitor indicator bacteria which provide indirect information on the water quality in the swimming pool. Three indicator microorganisms are often recommended: coliform counts (total coliforms, fecal coliforms or E. Coli), staphylococcus aureus and pseudomonas aeruginosa. A four year survey of the water quality of swimming pools in the Jerusalem District was conducted in order to determine whether the monitoring of all three indicators is necessary to assure safe water quality or is it sufficient to monitor only a single microorganism. A statistical analysis, conducted by using several different statistical techniques, reveals that the populations of the three indicator organisms are significantly interdependent but the correlations between each pair of these indicators are not sufficient to base a prediction of any of the organisms based on the measurements of the others. Therefore, it is concluded that monitoring of all three indicators should be recommended in order to provide an adequate picture of the water quality in swimming pools.


1983 ◽  
Vol 29 (10) ◽  
pp. 1261-1269 ◽  
Author(s):  
W. J. Robertson ◽  
R. S. Tobin

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.


Author(s):  
Asja Korajkic ◽  
Brian McMinn ◽  
Valerie Harwood

Fecal pollution of recreational waters can cause scenic blight and pose a threat to public health, resulting in beach advisories and closures. Fecal indicator bacteria (total and fecal coliforms, Escherichia coli, and enterococci), and alternative indicators of fecal pollution (Clostridium perfringens and bacteriophages) are routinely used in the assessment of sanitary quality of recreational waters. However, fecal indicator bacteria (FIB), and alternative indicators are found in the gastrointestinal tract of humans, and many other animals and therefore are considered general indicators of fecal pollution. As such, there is room for improvement in terms of their use for informing risk assessment and remediation strategies. Microbial source tracking (MST) genetic markers are closely associated with animal hosts and are used to identify fecal pollution sources. In this review, we examine 73 papers generated over 40 years that reported the relationship between at least one indicator and one pathogen group or species. Nearly half of the reports did not include statistical analysis, while the remainder were almost equally split between those that observed statistically significant relationships and those that did not. Statistical significance was reported less frequently in marine and brackish waters compared to freshwater, and the number of statistically significant relationships was considerably higher in freshwater (p < 0.0001). Overall, significant relationships were more commonly reported between FIB and pathogenic bacteria or protozoa, compared to pathogenic viruses (p: 0.0022–0.0005), and this was more pronounced in freshwater compared to marine. Statistically significant relationships were typically noted following wet weather events and at sites known to be impacted by recent fecal pollution. Among the studies that reported frequency of detection, FIB were detected most consistently, followed by alternative indicators. MST markers and the three pathogen groups were detected least frequently. This trend was mirrored by reported concentrations for each group of organisms (FIB > alternative indicators > MST markers > pathogens). Thus, while FIB, alternative indicators, and MST markers continue to be suitable indicators of fecal pollution, their relationship with waterborne pathogens, particularly viruses, is tenuous at best and influenced by many different factors such as frequency of detection, variable shedding rates, differential fate and transport characteristics, as well as a broad range of site-specific factors such as the potential for the presence of a complex mixture of multiple sources of fecal contamination and pathogens.


2013 ◽  
Vol 80 (5) ◽  
pp. 1588-1594 ◽  
Author(s):  
Orin C. Shanks ◽  
Catherine A. Kelty ◽  
Lindsay Peed ◽  
Mano Sivaganesan ◽  
Thomas Mooney ◽  
...  

ABSTRACTCalves make up about 16% of the current bovine population in the United States and can excrete high levels of human pathogens in their feces. We describe the density and distribution of genetic markers from 9 PCR- and real-time quantitative PCR-based assays, including CF128, CF193, CowM2, CowM3, GenBac3, Entero1, EC23S857, CampF2, and ttr-6, commonly used to help assess ambient surface water quality. Each assay was tested against a collection of 381 individual bovine fecal samples representing 31 mother and calf pairings collected over a 10-month time period from time of birth through weaning. Genetic markers reported to be associated with ruminant and/or bovine fecal pollution were virtually undetected in calves for up to 115 days from birth, suggesting that physiological changes in calf ruminant function impact host-associated genetic marker shedding. In addition, general fecal indicator markers forBacteroidales,Escherichia coli, andEnterococcusspp. exhibited three separate trends across time, indicating that these bacteria respond differently to age-related physiological and dietary changes during calf development. The results of this study suggest that currently available PCR-based water quality indicator technologies can under- or overestimate fecal pollution originating from calves and identify a need for novel calf-associated source identification methods.


2001 ◽  
Vol 44 (4) ◽  
pp. 97-101 ◽  
Author(s):  
M. Rojas Oropeza ◽  
N. Cabirol ◽  
S. Ortega ◽  
L. P. Castro Ortiz ◽  
A. Noyola

In this work, two egg-shaped, 5L-volume, anaerobic sludge digesters were used, one under mesophilic conditions (35°C, M1), and the other under thermophilic conditions (55°C, T1). Both digesters were fed with the purged sludge from an anaerobic treatment plant (start-up period) and from an activated sludge plant (stabilization period), treating municipal wastewaters. The purpose of the study was to establish the technical feasibility of the anaerobic thermophilic sludge treatment comparatively, during the stages of start-up and stabilization of the process, for removing pathogenic microorganisms and parasites efficiently. The results show that, in both stages, the anaerobic thermophilic digester presents higher efficiency on the removal of pathogens and parasites, than the mesophilic digester. Anaerobic thermophilic digestion is close to complying with the EPA (1996) limits for “Class A” type biosolids, referring to the number of parasitic helminth eggs (0.25 HELarval/gTS), and to the pathogen indicator fecal coliforms (&lt;1000 MPN/gTS). Therefore, the results show that thermophilic anaerobic digestion of biologic sludge may be considered as a suitable technology for the production of Class A biosolids, for further use in agriculture without restrictions.


1992 ◽  
Vol 26 (9-11) ◽  
pp. 2185-2189 ◽  
Author(s):  
S. R. Rippey ◽  
W. D. Watkins

The densities of several microbial indicator organisms, including fecal coliforms, enterococci, Clostridiumperfrinaens, and a male-specific bacteriophage group, were determined in the pre- and post-chlorinated effluents of three wastewater treatment plants during a rainfall event when the plants were operating near maximum flow capacity. These studies were undertaken to determine the effects of elevated flow rates on the relative rates of inactivation of the microbial indicators due to chlorine disinfection. Three distinctly different responses to chlorine treatment were observed. The vegetative bacterial organisms (fecal coliforms and enterococci) were most sensitive, the male-specific bacteriophage group was considerably more refractory, and c. perfringens, a bacterial spore-former, was highly resistant to inactivation by the disinfecting agent. These findings are significant for two reasons. First, the vegetative bacterial indicators did not reliably index the decay rates of the bacterial virus under the field conditions experienced. This has important public health ramifications to consumers of certain seafood products and to marine recreationists. Second, because of the highly refractory nature of the c. perfrinaens spore, this microbial indicator has practical use in assessing the magnitude of the impacts (source strengths) of sewage contaminated wastewaters on estuarine and marine environments.


Author(s):  
Rianna T. Murray ◽  
Rachel E. Rosenberg Goldstein ◽  
Elisabeth F. Maring ◽  
Daphne G. Pee ◽  
Karen Aspinwall ◽  
...  

Although many U.S. homes rely on private wells, few studies have investigated the quality of these water sources. This cross-sectional study evaluated private well water quality in Maryland, and explored possible environmental sources that could impact water quality. Well water samples (n = 118) were collected in four Maryland counties and were analyzed for microbiological and chemical contaminants. Data from the U.S. Census of Agriculture were used to evaluate associations between the presence of animal feeding operations and well water quality at the zip code level using logistic regression. Overall, 43.2% of tested wells did not meet at least one federal health-based drinking water standard. Total coliforms, fecal coliforms, enterococci, and Escherichia coli were detected in 25.4%, 15.3%, 5.1%, and 3.4% of tested wells, respectively. Approximately 26%, 3.4%, and <1% of wells did not meet standards for pH, nitrate-N, and total dissolved solids, respectively. There were no statistically significant associations between the presence of cattle, dairy, broiler, turkey, or aquaculture operations and the detection of fecal indicator bacteria in tested wells. In conclusion, nearly half of tested wells did not meet federal health-based drinking water standards, and additional research is needed to evaluate factors that impact well water quality. However, homeowner education on well water testing and well maintenance could be important for public health.


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