scholarly journals Lack of Direct Effects of Agrochemicals on Zoonotic Pathogens and Fecal Indicator Bacteria

2012 ◽  
Vol 78 (22) ◽  
pp. 8146-8150 ◽  
Author(s):  
Zachery R. Staley ◽  
Jacob K. Senkbeil ◽  
Jason R. Rohr ◽  
Valerie J. Harwood

ABSTRACTAgrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival ofEscherichia coli,Enterococcus faecalis,Salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect.

2018 ◽  
Vol 84 (16) ◽  
Author(s):  
Christina Frick ◽  
Julia Vierheilig ◽  
Rita Linke ◽  
Domenico Savio ◽  
Horst Zornig ◽  
...  

ABSTRACTQuantitative information regarding the presence ofEscherichia coli, intestinal enterococci, andClostridium perfringensin poikilotherms is notably scarce. Therefore, this study was designed to allow a systematic comparison of the occurrence of these standard fecal indicator bacteria (SFIB) in the excreta of wild homeothermic (ruminants, boars, carnivores, and birds) and poikilothermic (earthworms, gastropods, frogs, and fish) animals inhabiting an alluvial backwater area in eastern Austria. With the exception of earthworms, the average concentrations ofE. coliand enterococci in the excreta of poikilotherms were equal to or only slightly lower than those observed in homeothermic excreta and were 1 to 4 orders of magnitude higher than the levels observed in the ambient soils and sediments. Enterococci reached extraordinarily high concentrations in gastropods. Additional estimates of the daily excreted SFIB (E. coliand enterococcus) loads (DESL) further supported the importance of poikilotherms as potential pollution sources. The newly established DESL metric also allowed comparison to the standing stock of SFIB in the sediment and soil of the investigated area. In agreement with its biological characteristics, the highest concentrations ofC. perfringenswere observed in carnivores. In conclusion, the long-standing hypothesis that only humans and homeothermic animals are primary sources of SFIB is challenged by the results of this study. It may be necessary to extend the fecal indicator concept by additionally considering poikilotherms as potential important primary habitats of SFIB. Further studies in other geographical areas are needed to evaluate the general significance of our results. We hypothesize that the importance of poikilotherms as sources of SFIB is strongly correlated with the ambient temperature and would therefore be of increased significance in subtropical and tropical habitats and water resources.IMPORTANCEThe current fecal indicator concept is based on the assumption that the standard fecal indicator bacteria (SFIB)Escherichia coli, intestinal enterococci, andClostridium perfringensmultiply significantly only in the guts of humans and other homeothermic animals and can therefore indicate fecal pollution and the potential presence of pathogens from those groups. The findings of the present study showed that SFIB can also occur in high concentrations in poikilothermic animals (i.e., animals with body temperatures that vary with the ambient environmental temperature, such as fish, frogs, and snails) in an alluvial backwater area in a temperate region, indicating that a reconsideration of this long-standing indicator paradigm is needed. This study suggests that poikilotherms must be considered to be potential primary sources of SFIB in future studies.


2013 ◽  
Vol 79 (7) ◽  
pp. 2488-2492 ◽  
Author(s):  
Asja Korajkic ◽  
Brian R. McMinn ◽  
Valerie J. Harwood ◽  
Orin C. Shanks ◽  
G. Shay Fout ◽  
...  

ABSTRACTUsingin situsubtropical aquatic mesocosms, fecal source (cattle manure versus sewage) was shown to be the most important contributor to differential loss in viability of fecal indicator bacteria (FIB), specifically enterococci in freshwater andEscherichia coliin marine habitats. In this study, sunlight exposure and indigenous aquatic microbiota were also important contributors, whose effects on FIB also differed between water types.


2011 ◽  
Vol 77 (24) ◽  
pp. 8765-8774 ◽  
Author(s):  
Zachery R. Staley ◽  
Jason R. Rohr ◽  
Valerie J. Harwood

ABSTRACTWater bodies often receive agrochemicals and animal waste carrying fecal indicator bacteria (FIB) and zoonotic pathogens, but we know little about the effects of agrochemicals on these microbes. We assessed the direct effects of the pesticides atrazine, malathion, and chlorothalonil and inorganic fertilizer onEscherichia coliand enterococcal survival in simplified microcosms held in the dark.E. colistrain composition in sediments and water column were positively correlated, but none of the agrochemicals had significant direct effects onE. colistrain composition or on densities of culturable FIBs. In a companion study, microcosms with nondisinfected pond water and sediments were exposed to or shielded from sunlight to examine the potential indirect effects of atrazine and inorganic fertilizer onE. coli. The herbicide atrazine had no effect onE. coliin dark-exposed microcosms containing natural microbial and algal communities. However, in light-exposed microcosms, atrazine significantly loweredE. colidensities in the water column and significantly increased densities in the sediment compared to controls. This effect appears to be mediated by the effects of atrazine on algae, given that atrazine significantly reduced phytoplankton, which was a positive and negative predictor ofE. colidensities in the water column and sediment, respectively. These data suggest that atrazine does not directly affect the survival of FIB, rather that it indirectly alters the distribution and abundance ofE. coliby altering phytoplankton and periphyton communities. These results improve our understanding of the influence of agricultural practices on FIB densities in water bodies impacted by agricultural runoff.


2015 ◽  
Vol 81 (14) ◽  
pp. 4801-4808 ◽  
Author(s):  
M. D. Stocker ◽  
Y. A. Pachepsky ◽  
R. L. Hill ◽  
D. R. Shelton

ABSTRACTOnce released, manure-borne bacteria can enter runoff via interaction with the thin mixing layer near the soil surface. The objectives of this work were to document temporal changes in profile distributions of manure-borneEscherichia coliand enterococci in the near-surface soil layers after simulated rainfalls and to examine differences in survival of the two fecal indicator bacteria. Rainfall simulations were performed in triplicate on soil-filled boxes with grass cover and solid manure application for 1 h with rainfall depths of 30, 60, and 90 mm. Soil samples were collected weekly from depth ranges of 0 to 1, 1 to 2, 2 to 5, and 5 to 10 cm for 1 month. Rainfall intensity was found to have a significant impact on the initial concentrations of fecal indicator bacteria in the soil. While total numbers of enterococci rapidly declined over time,E. colipopulations experienced initial growth with concentration increases of 4, 10, and 25 times the initial levels at rainfall treatment depths of 30, 60, and 90 mm, respectively.E. colipopulations grew to the approximately the same level in all treatments. The 0- to 1-cm layer contained more indicator bacteria than the layers beneath it, and survival of indicator bacteria was better in this layer, with decimation times between 12 and 18 days after the first week of growth. The proportion of bacteria in the 0- to 1-cm layer grew with time as the total number of bacteria in the 0- to 10-cm layer declined. The results of this work indicate the need to revisit the bacterial survival patterns that are assumed in water quality models.


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.


2018 ◽  
Vol 94 (11) ◽  
Author(s):  
Karen Shapiro ◽  
Mary Silver ◽  
Barbara A Byrne ◽  
Terra Berardi ◽  
Beatriz Aguilar ◽  
...  

2012 ◽  
Vol 78 (12) ◽  
pp. 4225-4232 ◽  
Author(s):  
Catherine A. Kelty ◽  
Manju Varma ◽  
Mano Sivaganesan ◽  
Richard A. Haugland ◽  
Orin C. Shanks

ABSTRACTVery little is known about the density and distribution of fecal indicator bacteria (FIB) genetic markers measured by quantitative real-time PCR (qPCR) in fecal pollution sources. Before qPCR-based FIB technologies can be applied to waste management and public health risk applications, it is vital to characterize the concentrations of these genetic markers in pollution sources (i.e., untreated wastewater and animal feces). We report the distribution of rRNA genetic markers for several general FIB groups, includingClostridiumspp.,Escherichia coli, enterococci, andBacteroidales, as determined by qPCR on reference collections consisting of 54 primary influent sewage samples collected from treatment facilities across the United States and fecal samples representing 20 different animal species. Based on raw sewage sample collection data, individual FIB genetic markers exhibited a remarkable similarity in concentration estimates from locations across the United States ranging from Hawaii to Florida. However, there was no significant correlation between genetic markers for most FIB combinations (P> 0.05). In addition, large differences (up to 5 log10copies) in the abundance of FIB genetic markers were observed between animal species, emphasizing the importance of indicator microorganism selection and animal source contribution for future FIB applications.


Oceanography ◽  
2008 ◽  
Vol 21 (3) ◽  
pp. 98-106 ◽  
Author(s):  
Karen Knee ◽  
Rose Leopold ◽  
Ella Madsen ◽  
Adina Paytan

Sign in / Sign up

Export Citation Format

Share Document