Influences of sample interference and interference controls on quantification of enterococci fecal indicator bacteria in surface water samples by the qPCR method

2012 ◽  
Vol 46 (18) ◽  
pp. 5989-6001 ◽  
Author(s):  
Richard A. Haugland ◽  
Shawn Siefring ◽  
Jennifer Lavender ◽  
Manju Varma
2014 ◽  
pp. 111-134 ◽  
Author(s):  
Richard L. Whitman ◽  
Meredith B. Nevers ◽  
Katarzyna Przybyla-Kelly ◽  
Muruleedhara N. Byappanahalli

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2824
Author(s):  
Daniel Salvador ◽  
Maria Filomena Caeiro ◽  
Fátima Serejo ◽  
Paulo Nogueira ◽  
Rui Neves Carneiro ◽  
...  

Monitoring the quality of water is a requisite to prevent outbreaks related to waterborne diseases, predominantly caused by pathogens like enteric viruses, usually transmitted via the fecal-oral route. This study aimed to survey a group of enteric viruses (Enterovirus, Norovirus genogroups I and II, and hepatitis A virus) in two surface water sources of drinking water, also intending to evaluate the extent of their elimination in the two water treatment plants (WTPs) involved in drinking water production. Correlations between these viruses and fecal indicator bacteria (FIB) were also evaluated. Positive samples for viral RNA were recurrently found by reverse transcription quantitative PCR (RT-qPCR) and quantified, in genomic copies per liter (gc/L) of sampled water. Viral RNAs were detected in 14 out of 27 samples of surface water, and 21 out of 36 samples of drinking water, NoV II having been the most frequently detected in both (0–78.6 gc/L and 0–12.5 gc/L, respectively). Both WTPs showed variable efficacies in the elimination of viral RNA. Only one correlation was found with FIB, between NoV II and intestinal enterococci. These results recommend the monitoring of enteric viruses over time and their inclusion in the mandatory analysis of water quality.


Author(s):  
Zahra Mirshekar ◽  
Ali Shahryari ◽  
Mohamad Gharekhan Alostani ◽  
Rahim Aali

Introduction: As recommended by World Health Organization, consumption of the fungal contaminated water does not cause to serious infection, but may lead to healthy or aesthetic problems. The aim of this research was to assess the occurrence of fungi in water and its relationship with fecal indicator bacteria. Materials and Methods: 110 water samples were collected from different location of water distribution systems in Aliabad-e Katul City, North of Iran during April to November 2018. Enumeration of coliforms bacteria and fungi were performed by multiple tube fermentation and membrane filtration method, respectively; as described in Standard Methods. Results: Our results showed that fungi and total coliform were detected in 31 (28.4%) and 26 (23.9%) samples, respectively. Among samples of fungi positive, 22 (20.2%), 7 (6.4%), and 5 (4.6%) water samples were positive for Aspergillus sp., Rhizopus sp., and Penicillium sp., respectively. However, none faecal coliform and E. coli were observed in all examined samples, proposing the absence of faecal pollution in water. The mean and SD residual chlorine and pH were 0.55 ± 0.23 (mg/l) and 7.30 ± 0.30, respectively. The statistical analysis showed a remarkable difference between the prevalence of total coliforms and fungal species (P < 0.001). Conclusion: Presence of potential opportunistic pathogens fungi in potable water can be considered as a health risk, especially for immuno-suppressed individuals. Therefore, cleaning the processes such as biofilm removal and addition of the free chlorine concentration can be effective to decrease fungi contamination and total coliform from water distribution system.


2012 ◽  
Vol 58 (12) ◽  
pp. 1405-1410 ◽  
Author(s):  
Emilie Lyautey ◽  
Alain Hartmann ◽  
David R. Lapen ◽  
Edward Topp

Listeria monocytogenes is a facultative intracellular pathogen distributed in the environment. Reference isolation methods include an enrichment step. We compared 2 protocols: one based on enrichment and the other on direct plating, with respect to the efficiency of isolation of L. monocytogenes from surface water samples. From March to May 2006, 126 surface water samples were collected biweekly from 24 discrete sampling sites located in the South Nation River basin (Ontario). Presumptive Listeria spp. were isolated using the 2 methods, and L. monocytogenes isolates were confirmed based on colony morphology and amplification of 3 pathogenicity genes: iap, inlA, and hlyA. Listeria monocytogenes was detected in 31 water samples using the enrichment approach and in 27 using the direct-plating approach, with only 13 samples positive using both approaches. No correlation was observed between the ability of the enrichment procedure to fail in the detection of the pathogenic bacterium and the abundance of several indicator bacteria. The proportion of samples carrying isolates from serovar groups 1/2a, 3a; 1/2b, 3b, 7; 4b, 4d, 4e; and Listeria spp. was significantly different between the 2 approaches. This data indicate that a direct-plating approach would be suitable for the detection of L. monocytogenes in water samples, but that enrichment and direct-plating protocols both have specific biases.


2006 ◽  
Vol 6 (2) ◽  
pp. 47-53 ◽  
Author(s):  
D. Simazaki ◽  
M. Asami ◽  
T. Nishimura ◽  
S. Kunikane ◽  
T. Aizawa ◽  
...  

Nationwide surveys of 1,4-dioxane and methyl-t-butyl ether (MTBE) levels in raw water used for the drinking water supply were conducted at 91 water treatment plants in Japan in 2001 and 2002, prior to the revision of the drinking water quality standards. 1,4-dioxane was widely and continuously detected in raw water samples and its occurrence was more frequent and its concentrations higher in groundwater than in surface water. However, its maximum concentration in raw water was much lower than its new standard value (50 μg/L), which was determined as a level of 10−5 excessive cancer risk to humans. Trace levels of MTBE were also detected in several surface water samples.


Author(s):  
Kamran Bashir ◽  
Zhimin Luo ◽  
Guoning Chen ◽  
Hua Shu ◽  
Xia Cui ◽  
...  

Griseofulvin (GSF) is clinically employed to treat fungal infections in humans and animals. GSF was detected in surface waters as a pharmaceutical pollutant. GSF detection as an anthropogenic pollutant is considered as a possible source of drug resistance and risk factor in ecosystem. To address this concern, a new extraction and enrichment method was developed. GSF-surface molecularly imprinted polymers (GSF-SMIPs) were prepared and applied as solid phase extraction (SPE) sorbent. A dispersive solid phase extraction (DSPE) method was designed and combined with HPLC for the analysis of GSF in surface water samples. The performance of GSF-SMIPs was assessed for its potential to remove GSF from water samples. The factors affecting the removal efficiency such as sample pH and ionic strength were investigated and optimized. The DSPE conditions such as the amount of GSF-SMIPs, the extraction time, the type and volume of desorption solvents were also optimized. The established method is linear over the range of 0.1–100 µg/mL. The limits of detection and quantification were 0.01 and 0.03 µg/mL respectively. Good recoveries (91.6–98.8%) were achieved after DSPE. The intra-day and inter-day relative standard deviations were 0.8 and 4.3% respectively. The SMIPs demonstrated good removal efficiency (91.6%) as compared to powder activated carbon (67.7%). Moreover, the SMIPs can be reused 10 times for water samples. This is an additional advantage over single-use activated carbon and other commercial sorbents. This study provides a specific and sensitive method for the selective extraction and detection of GSF in surface water samples.


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