Assessment of the decay rates of microbial source tracking molecular markers and faecal indicator bacteria from different sources

2018 ◽  
Vol 125 (6) ◽  
pp. 1938-1949 ◽  
Author(s):  
E. Ballesté ◽  
C. García-Aljaro ◽  
A.R. Blanch
2016 ◽  
Vol 82 (22) ◽  
pp. 6757-6767 ◽  
Author(s):  
Marek Kirs ◽  
Roberto A. Caffaro-Filho ◽  
Mayee Wong ◽  
Valerie J. Harwood ◽  
Philip Moravcik ◽  
...  

ABSTRACTIdentification of sources of fecal contaminants is needed to (i) determine the health risk associated with recreational water use and (ii) implement appropriate management practices to mitigate this risk and protect the environment. This study evaluated human-associatedBacteroidesspp. (HF183TaqMan) and human polyomavirus (HPyV) markers for host sensitivity and specificity using human and animal fecal samples collected in Hawaii. The decay rates of those markers and indicator bacteria were identified in marine and freshwater microcosms exposed and not exposed to sunlight, followed by field testing of the usability of the molecular markers. Both markers were strongly associated with sewage, although the cross-reactivity of the HF183TaqMan (also present in 82% of canine [n= 11], 30% of mongoose [n= 10], and 10% of feline [n= 10] samples) needs to be considered. Concentrations of HF183TaqMan in human fecal samples exceeded those in cross-reactive animals at least 1,000-fold. In the absence of sunlight, the decay rates of both markers were comparable to the die-off rates of enterococci in experimental freshwater and marine water microcosms. However, in sunlight, the decay rates of both markers were significantly lower than the decay rate of enterococci. While both markers have their individual limitations in terms of sensitivity and specificity, these limitations can be mitigated by using both markers simultaneously; ergo, this study supports the concurrent use of HF183TaqMan and HPyV markers for the detection of sewage contamination in coastal and inland waters in Hawaii.IMPORTANCEThis study represents an in-depth characterization of microbial source tracking (MST) markers in Hawaii. The distribution and concentrations of HF183TaqMan and HPyV markers in human and animal fecal samples and in wastewater, coupled with decay data obtained from sunlight-exposed and unexposed microcosms, support the concurrent application of HF183TaqMan and HPyV markers for sewage contamination detection in Hawaii waters. Both markers are more conservative and more specific markers of sewage than fecal indicator bacteria (enterococci andEscherichia coli). Analysis of HF183TaqMan (or newer derivatives) is recommended for inclusion in future epidemiological studies concerned with beach water quality, while better concentration techniques are needed for HPyV. Such epidemiological studies can be used to develop new recreational water quality criteria, which will provide direct information on the absence or presence of sewage contamination in water samples as well as reliable measurements of the risk of waterborne disease transmission to swimmers.


2013 ◽  
Vol 80 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Adelumola Oladeinde ◽  
Thomas Bohrmann ◽  
Kelvin Wong ◽  
S. T. Purucker ◽  
Ken Bradshaw ◽  
...  

ABSTRACTUnderstanding the survival of fecal indicator bacteria (FIB) and microbial source-tracking (MST) markers is critical to developing pathogen fate and transport models. Although pathogen survival in water microcosms and manure-amended soils is well documented, little is known about their survival in intact cow pats deposited on pastures. We conducted a study to determine decay rates of fecal indicator bacteria (Escherichia coliand enterococci) and bovine-associated MST markers (CowM3, Rum-2-bac, and GenBac) in 18 freshly deposited cattle feces from three farms in northern Georgia. Samples were randomly assigned to shaded or unshaded treatment in order to determine the effects of sunlight, moisture, and temperature on decay rates. A general linear model (GLM) framework was used to determine decay rates. Shading significantly decreased the decay rate of theE. colipopulation (P< 0.0001), with a rate of −0.176 day−1for the shaded treatment and −0.297 day−1for the unshaded treatment. Shading had no significant effect on decay rates of enterococci, CowM3, Rum-2-bac, and GenBac (P> 0.05). In addition,E. colipopulations showed a significant growth rate (0.881 day−1) in the unshaded samples during the first 5 days after deposition. UV-B was the most important parameter explaining the decay rate ofE. colipopulations. A comparison of the decay behaviors among all markers indicated that enterococcus concentrations exhibit a better correlation with the MST markers thanE. coliconcentrations. Our results indicate that bovine-associated MST markers can survive in cow pats for at least 1 month after excretion, and although their decay dynamic differs from the decay dynamic ofE. colipopulations, they seem to be reliable markers to use in combination with enterococci to monitor fecal pollution from pasture lands.


2010 ◽  
Vol 62 (3) ◽  
pp. 586-593 ◽  
Author(s):  
P. Roslev ◽  
A. S. Bukh ◽  
L. Iversen ◽  
H. Sønderbo ◽  
N. Iversen

Sources of faecal pollution in coastal recreational waters may be identified by analysing different host associated microorganisms or molecular markers. However, the microbial targets are often present at low numbers in moderately impacted waters, and often exhibit significant temporal and spatial variability in waters with fluctuating faecal loads. This patchy occurrence can limit successful detection of relevant targets in microbial source tracking studies. In this study, we explored the possibility for using the blue mussel (Mytilus edulis) as a biosampler for accumulation of faecal bacteria relevant for microbial source tracking. Non-contaminated blue mussels were transferred to three coastal recreational waters affected by faecal pollution of unknown origin. Molecular markers associated with animal and human waste were targeted by PCR and compared in seawater and mussel samples. The results demonstrated that transplanted mussels in simple enclosures accumulated and retained elevated levels of molecular markers associated with different types of faecal pollution. The targets included a novel putative human associated E. coli subgroup B2 VIII clone, and animal and human associated markers in enterococci (esp, M19, M66, M90, and M91). Human (sewage) associated markers including esp and M66 were sometimes not detectable in seawater samples despite known wastewater contamination, whereas the markers were detectable in mussels. We suggest that transplanted mussels should be considered as potential biosamplers in studies focusing on identifying source of faecal pollution in low or moderately impacted recreational waters. Bioaccumulation of molecular markers in mussels for several days may represent the water quality better than traditional grab samples from the water column.


2013 ◽  
Vol 79 (8) ◽  
pp. 2682-2691 ◽  
Author(s):  
W. Ahmed ◽  
T. Sritharan ◽  
A. Palmer ◽  
J. P. S. Sidhu ◽  
S. Toze

ABSTRACTThis study was aimed at evaluating the host specificity and host sensitivity of two bovine feces-associated bacterial (BacCow-UCD and cowM3) and one viral [bovine adenovirus (B-AVs)] microbial source tracking (MST) markers by screening 130 fecal and wastewater samples from 10 target and nontarget host groups in southeast Queensland, Australia. In addition, 36 water samples were collected from a reservoir and tested for the occurrence of all three bovine feces-associated markers along with fecal indicator bacteria (FIB),Campylobacterspp.,Escherichia coliO157, andSalmonellaspp. The overall host specificity values of the BacCow-UCD, cowM3, and B-AVs markers to differentiate between bovine and other nontarget host groups were 0.66, 0.88, and 1.00, respectively (maximum value of 1.00). The overall host sensitivity values of these markers, however, in composite bovine wastewater and individual bovine fecal DNA samples were 0.93, 0.90, and 0.60, respectively (maximum value of 1.00). Among the 36 water samples tested, 56%, 22%, and 6% samples were PCR positive for the BacCow-UCD, cowM3, and B-AVs markers, respectively. Among the 36 samples tested, 50% and 14% samples were PCR positive for theCampylobacter16S rRNA andE. coliO157rfbEgenes, respectively. Based on the results, we recommend that multiple bovine feces-associated markers be used if possible for bovine fecal pollution tracking. Nonetheless, the presence of the multiple bovine feces-associated markers along with the presence of potential zoonotic pathogens indicates bovine fecal pollution in the reservoir water samples. Further research is required to understand the decay rates of these markers in relation to FIB and zoonotic pathogens.


2020 ◽  
Vol 178 ◽  
pp. 106068
Author(s):  
Dana Gonzalez ◽  
David Keeling ◽  
Hannah Thompson ◽  
Allison Larson ◽  
Jack Denby ◽  
...  

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