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Title, abstract, keywords Journal/book title
Water Research Volume 40, Issue 13 , July 2006, Pages 2463-2476
doi:10.1016/j.watres.2006.04.040 Copyright 2006 Elsevier Ltd All rights reserved.
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Review

Alternative indicators of fecal pollution: Relations with pathogens and conventional indicators, current methodologies for direct pathogen monitoring and future application perspectives
Olga Savichtchevaa and Satoshi Okabe , a,
aDepartment of Urban and Environmental Engineering, Graduate School of Engineering, Hokkaido University, North-13, West-8, Kita-ku, 060-8628 Sapporo, Japan
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Received 16 June 2005; revised 22 March 2006; accepted 25 April 2006. Available online 30 June 2006.

Abstract

The ecological and survival characteristics of bacterial, viral and parasitic pathogens vary under environmental conditions, indicating that probably no single indicator organism can predict the presence of all enteric pathogens for all types of waters and different hostassociated fecal pollution. If there are true correlations between indicator organisms and pathogens, it is necessary to find out to what extent and under which circumstances these organisms can be used as reliable indicators of fecal pollution. Application of conventional and alternative fecal indicators has greatly enhanced our abilities to predict and reduce health risk associated with the use of surface waters. New molecular-based techniques have shown that combined use of conventional and alternative indicators for fecal pollution increases both the detection sensitivity and specificity of fecal pollution and associated pathogens. In this review, we, therefore, summarize the advantages and limitations of conventional and alternative fecal indicators in terms of predicting pathogen presence as well as current and future methodologies for direct pathogen monitoring in environmental waters. This manuscript is mainly focused on the relationships between microbial fecal indicators and the presence of pathogens, which have not previously been summarized yet and could nicely supplement with recent literature reviews on microbial source tracking. Keywords: Microbial source tracking; Fecal pollution; Fecal indicator microorganisms; Alternative indicators of fecal pollution; Molecular-based techniques

Article Outline

1. Introduction 2. Alternative indicators of fecal pollution 3. Fecal anaerobes 3.1. Bacteroides spp. 3.2. Bifidobacterium spp. 3.3. Clostridium perfringens 4. Viral indicators 4.1. Bacteroides fragilis bacteriophage 4.2. Coliphages (F-specific RNA coliphage)
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5. Chemical compounds 6. Correlation between alternative and conventional fecal indicators with pathogens 7. Combined application of alternative and conventional fecal indicators 8. Methods for direct monitoring of pathogens in water environment 9. Conclusions and future directions Acknowledgements References

1. Introduction

Concerns with water quality have increased in recent years, in part due to frequent contamination of coastal and inland water resources by waterborne bacterial, viral and protozoan pathogens. The feces of animals may contain a variety of pathogenic microorganisms such as Campylobacter, Salmonella, Shigella, Yersinia, Aeromonas, Pasteurella, Franciella, Leptospira, Vibrio, some protozoa and several virus groups (Hurst et al., 2002). Fecal pollution could lead to the transmission of pathogens and, therefore, to waterborne diseases. This fecal material can be originated from point source discharges such as raw sewage, storm water, effluent from wastewater treatment plants and industrial sources (Seurinck et al., 2005). In addition, non-point source discharges such as agriculture, forestry, wildlife and urban run-off can also impair water quality (Seurinck et al., 2005). If the origin of fecal contamination and pathogens could be correctly identified, management and remediation efforts could be allocated in more-cost effective and efficient manner. Since the pathogens appear intermittently in natural waters at low concentrations, and detection and quantification of each pathogenic bacterium is labor-intensive and not easy to perform for most cases, the routine microbiological water analyses are based on detection of indicator organisms, which share the same habitats. The ideal fecal indicator should fulfill each and every one of the certain criteria such as consistently presence in the feces, inability to multiply outside the intestinal tract, be at least as resistant as the pathogens to environmental conditions and to disinfection, have a strong association with the presence of pathogenic microorganisms, and allow simple laboratory methodology (Hurst et al., 2002). Historically, fecal indicator bacteria (FIB) including total and fecal coliforms and enterococci have been used in many countries as a monitoring tool for microbiological impairment of water and for prediction of presence of bacterial, viral and protozoan pathogens. These microorganisms are of fecal origin from higher mammals and birds, and their presence in water may indicate fecal pollution and possible association with enteric pathogens. However, numerous limitations associated with their application including short survival in water body (McFeters et al., 1974; McFeters, 1990), non-fecal source (Scott et al., 2002; Simpson et al., 2002), ability to multiply after releasing into water column (Desmarais et al., 2002; Solo-Gabriele et al., 2000), great weakness to the disinfection process (Hurst et al., 2002), inability to identify the source of fecal contamination (point and non-point) (Field et al., 2003), low levels of correlation with the presence of pathogens and low sensitivity of detection methods have been widely reported (Horman et al., 2004; Winfield and Groisman, 2003). As a result, none of the bacterial indicators currently used meet all ideal criteria established for water quality. Difficulties related to conventional fecal indicators could be partly circumvented by using alternative biological and chemical fecal indicators including fecal anaerobes (genera Bacteroides (Bernhard and Field, 2000) and Bifidobacterium (Resnick and Levin, 1981)), Bacteroides fragilis phage (Jofre et al., 1986), coliphages (Borrego et al., 1987) and fecal organic compounds such as coprostanol (Leeming and Nichols, 1996). A big advantage of alternative indicators usage is that the source of fecal contamination and pathogens can be identified by using recently developed molecular tools (Scott et al., 2002; Simpson et al., 2002). Moreover, since one indicator might not represent the relative abundance of all pathogenic bacteria, viruses and protozoa, combined application of alternative indicators with conventional ones could lead to more comprehensive results about fecal contamination and its association with pathogenic microorganisms. Currently, there are very few review papers critically evaluating the relationships between conventional and alternative fecal indicators and the presence of bacterial, viral and protozoan pathogens (Horman et al., 2004; Noble and Fuhrman, 2001; Payment et al., 2000). In this review the application of alternative fecal indicators and their correlations with pathogens will be, therefore, emphasized. The advantages and disadvantages of currently used and alternative fecal indicators will be critically evaluated in terms of reliability for predicting fecal pollution and pathogen presence. Furthermore, current methodologies for direct monitoring of pathogens in environmental waters and future research directions will be discussed.

3.2. Bifidobacterium spp.
Ecological distribution of Bifidobacterium spp. is highly variable in animals (Bonjoch et al., 2004). Although feces from humans, chickens, cows, dogs, pigs, horses, cats, sheep, beavers, goats, and turkeys were investigated, Bifidobacterium spp. was isolated from only feces of humans and swine (Resnick and Levin, 1981). They were also frequently detected mainly from raw sewage and septic tanks (human feces), even though there was no significant difference in the concentrations of fecal coliforms, enterococci, or clostridia between human and animal fecal samples (Bonjoch et al., 2004; Resnick and Levin, 1981). Therefore, unlike Bifidobacterium spp., none of these conventional parameters can discriminate the origin of fecal pollution. This conclusion has been also confirmed for tropical freshwaters (Carrillo et al., 1985). PCR, multiplex PCR and real-time PCR approaches with strain-specific primers have been recently developed and applied for detection and quantification of host-associated
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Bifidobacterium spp. (Bonjoch et al., 2004; Matsuki et al., 2004; Nebra et al., 2003). During summer months Bifidobacterium spp. was no longer detectable after 59 days in water at 23 C and 30 C. However, these microorganisms have enhanced their persistence at low temperatures, surviving more than 4 weeks at 10 C (Maus and Ingham, 2003; Nebra et al., 2003; Rhodes and Kator, 1999). The relatively short survival time is presently a problem in terms of recovery of these microorganisms from water body. High background levels of predators and Gram-positive rods and cocci could prevent growth and/or detection of Bifidobacterium spp. in the aquatic environment (Rhodes and Kator, 1999). The transit time before filtration of environmental sample must be kept to a minimum (3 h), since only 60 70% of the population would be recovered (Resnick and Levin, 1981). At present, there is still little information about the persistence of Bifidobacterium markers in water environments and their geographical distributions. Similar to the application of Bacteroides spp., comprehensive studies on survival ability and correlation with presence of pathogens and waterborne diseases outbreaks should be further performed.
3.3. Clostridium perfringens
C. perfringens has been successfully used as fecal indicator for sewage-contaminated streams, ocean environments (Hurst et al., 2002) and sea water (Roll and Fujioka, 1997). As the majority of clostridia population forms spore, they are extremely resistant to the environmental stress and persist for longer time than other indicator bacteria (e.g., fecal coliforms and fecal streptococci) and most of pathogens do (Davies et al., 1995; Horman et al., 2004; Medema et al., 1997). Temperature and predators did not significantly affect the survival rates of this microorganism. Therefore, spores of C. perfringens represent one of the most conservative indicators of fecal pollution. Spore-forming bacteria are especially useful to determine the ultimate fate of sewage or storm water released into water body. C. perfringens may be ideal microorganisms to evaluate the completeness of disinfection in drinking water treatment processes (Payment and Franco, 1993; Payment et al., 2000). A criticism of proposed C. perfringens usage is that they have extended viability and wide distributions in aquatic sediments. Spores of C. perfringens can be detected even in long distance from contamination sites, indicating remote or old fecal pollution (Desmarais et al., 2002; Sorensen et al., 1989). Additionally, their concentrations vary among different animal species. Feces of cattle, horse and sheep contain less C. perfringens than human feces do (Sorensen et al., 1989). Similar to many alternative fecal indicators, C. perfringens standards have not yet been evaluated based on epidemiological studies on the acceptable risk associated with fecal pollution.

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al., 2004) in various environmental waters. Multiplex PCR format has been rather recognized as a rapid and highly sensitive tool for simultaneous detection of many microorganisms in a single PCR tube (Franck et al., 1998; Fukushima et al., 2002). Clinical isolates of V. cholera and those from the environments can be distinguished on the basis of multiplex PCR for the presence of V. cholera O1, O139, non-O1, and non-O139 strains (Singh et al., 2001). Real-time PCR technique, which uses fluorescence-based detection of target gene sequence, allows real time quantitative monitoring of organisms of interest (Heid et al., 1996; Hein et al., 2001; Huijsdens et al., 2002; Malinen et al., 2003; Matsuki et al., 2004; Novga et al., 2000). Applications of 5 nuclease PCR for quantitative detection of Listeria monocytogenes and Campylobacter jejuni have been described (Novga et al., 2000) as well as multiplex real-time PCR technology for detection and quantification of E. coli O157:H7 (Ibekwe et al., 2002). Terminal restriction fragment length polymorphism (T-RFLP) and length heterogeneity PCR take advantages of unique genetic markers to discriminate between different microorganisms that allows identifying the origin of fecal pollution (Bernhard and Field, 2000a and Bernhard and Field, 2000b; Blackwood et al., 2003; Nagashima et al., 2003). Recent advances in molecular characterization of Cryptosporidium spp. achieved sensitive identification and differentiation of this pathogen in water samples for the evaluation of the fecal contamination source (Xiao et al., 2001). A small-subunit rRNA (SSU rRNA) genebased nested PCR-restriction fragment length polymorphism (RFLP) technique was developed and applied for the differentiation of Cryptosporidium spp. and C. parvum strains in fecal samples from humans and animals (Xiao et al., 2001). Fingerprinting techniques such as amplified fragment length polymorphism (AFLP) and enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) have been used to determine the differences in host-specific E. coli strains with respect to their pathogenicity (Guan et al., 2002; Leung et al., 2004; Parveen et al., 1999). In this respect, the repetitive sequencebased polymerase chain reaction (rep-PCR) has been successfully used to classify the number of different bacterial species, which has been impossible to do based on the standard culture-based methods (Dombek et al., 2000; Seurinck et al., 2003). Despite that the PCR-based methods have been widely applied for direct pathogen detection, some problematic issues still exist. Interpreting the results from a PCR assay is more complicated than simple conclusion about presence or absence of pathogens. A positive result certainly provides an indication of pathogen contamination, while a negative result is very difficult to interpret without knowing the precise detection limit for the assay (Loge et al., 2002). Detection limits depend on series of factors including volume of filtered water sample (Loge et al., 2002), the efficiency of nucleic acid extraction (Head et al., 1998), the presence of inhibitory compounds in the PCR reaction (Loge et al., 2002) and formation of chimeric PCR products (Kreader, 1996). The PCR efficiency also depends on chosen PCR conditions and specificity of primer sets. To increase the detection probability of pathogens, pre-culturing was sometimes conducted. This step, however, does not allow quantitative measurements of pathogens; only presence or absence of pathogens can be evaluated. Importantly, DNA-based PCR methods do not show the ability to distinguish between viable and non-viable organisms since DNA of both live and dead cells can be amplified. In this respect, detection of SSU rRNA seems to be a promising tool for both detection of certain microorganisms and estimation of their viability in the environments since the copy numbers of it have certain relationship to the metabolic activity. For this reason, reverse transcription PCR (Burtscher and Wuertz, 2003), real time RT-PCR (Fey et al., 2004; Gibson et al., 1996), multiplex RT-PCR, fluorescence in situ hybridazation (FISH) (Amann and Schleifer, 1995) and DNA microarray techniques (Chizhikov et al., 2001) have received increasing attentions. Application of these methods seems to be promising as a tool for detection and quantification of viable microorganisms in the studies where survival ability of specific organisms is under special interest. For example, quantitative RT-PCR has been successfully used for quantification of the metabolically active Salmonella spp. in different environmental water samples (Fey et al., 2004). Whole cell in situ hybridization (FISH) with fluorescently labeled oligonucleotide probes has been widely introduced to environmental microbial ecology (Head et al., 1998; Okabe et al., 1999). Based on designed probes, binding complimentary rRNA sequences, this method allows to detect metabolically active microbial community of interest and also to quantify them (Pernthaler and Amann, 2004; Savichtcheva et al., 2005). This technique was applied for rapid detection, identification, and enumeration of E. coli cells in municipal wastewaters (Stender et al., 2001). Genome sequencing projects have stimulated radical changes in experimental methodology from those focused on one gene at a time to those aimed to study thousands of genes or proteins at once. Thus, DNA microarray-based technologies have revolutionized the ability to simultaneously carry out hundreds or thousands of hybridization reactions at a time, showing massive screening capacity resulting in a high level of sensitivity, specificity, and output capacity (Vora et al., 2004). The DNA microarray technique has been successfully applied for detection of microbial virulence factors (Chizhikov et al., 2001; Vora et al., 2004) and for quantification of bacterial DNAs in environmental samples (Cho and Tiedji,

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2002). Genetic characterization of Salmonella enterica strains (Alvarez et al., 2003) and detection of different pathogens including enterohemorrhagic E. coli (EHEC) O157:H7 (Vora et al., 2004), six species of Listeria genus (Volokhov et al., 2002), and human group A rotaviruses (Chizhikov et al., 2002) have also been performed using the microarray analyses. Further works on PCR-based assay, e.g., maximizing nucleic acid extraction and PCR amplification, might improve detection limits of these promising molecular techniques for direct pathogen monitoring in different water bodies. Spatial and temporal variations, reproducibility and reliability of the results, and stability of used genetic markers are crucial for direct detection of pathogens as well as for microbial source tracking. Additionally, technical expertise, equipments and professional staffs engaged in these studies are often limited for many countries. Thus, the need for the improvement and development of reproducible, reliable and easy to perform techniques is still of great interest.
9. Conclusions and future directions
Until now, little is still known about survival/persistence of both indicator microorganisms and bacterial, protozoan and viral pathogens under different environmental conditions within primary and secondary habitats, which is central in pathogen impact. The better understanding of the sources of microbial contaminants (human versus animal), their transport, prevalence, and fate in water environments, and the resulting public health risks is urgently needed. The development of alternative fecal indicators to replace or to combine with conventional ones requires additional adequate investigation and epidemiological survey on their applications. It has become more evident that combination of traditional culture-dependent methods for conventional fecal indicators with molecular-based techniques can successfully lead to more conclusive results of fecal contamination. The distribution of host-specific genetic markers including humans has not been extensively investigated yet, leaving a large space for additional future researches on identification of the source of fecal pollution. In addition, further collaborative development of methodologies and studies on fecal indicators suitable for different climatic regions are still important tasks for environmental microbiologists to provide a more futuristic vision of environmental monitoring.

Acknowledgments

Olga Savichtcheva was supported by Japanese Government (MONBUKAGAKUSHO) scholarship. We thank Dr. Tsukasa Ito, Dr. Karla Patricia Santos Oliveira Rodriguez Esquerre, Noriko Okayama and Herto Dwi Ariesyady for valuable assistance and discussions during preparation of the manuscript.

References

Alvarez et al., 2003 J. Alvarez, S. Porwollik, I. Laconcha, V. Gisakis, A.B. Vivanco, I. Gonzalez, S. Echenagusia, N. Zabala, F. Blackmer, M. McClelland, A. Rementeria and J. Garaizar, Detection of a Salmonella enterica serovar California strain spreading in Spanish feed mills and genetic characterization with DNA microarrays, Appl. Environ. Microbiol. 69 (2003), pp. 75317534. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Amann and Schleifer, 1995 R.I. Amann and K.-H. Schleifer, Phylogenetic identification and in situ detection of individual microbial cells without cultivation, Microbiol. Rev. 59 (1995), pp. 143169. Abstract + References in Scopus | Cited By in Scopus Audicana et al., 1995 A. Audicana, I. Perales and J.J. Borrego, Modification of kanamycin esculinazide agar to improve selectivity in the enumeration of fecal streptococci from water samples, Appl. Environ. Microbiol. 61 (1995), pp. 41784183. Abstract + References in Scopus | Cited By in Scopus Avelar et al., 1998 K.E.S. Avelar, S.R. Moraes, LJ.F. Pinto, W.das G.S. Souza, R.M.C.P. Domingues and M.C. de S. Ferreira, Influence of stress conditions on Bacteroides fragilis survival and protein profiles, Zentralbl. Bakteriol. 287 (1998), pp. 399409. Abstract + References in Scopus | Cited By in Scopus Boehm et al., 2003 A.B. Boehm, J.A. Fuhrman, R.D. Mrse and S.B. Grant, Tired approach for identification of a human fecal pollution source at a recreational beach: case study at Avalon Bay, Catalina Island, California, Environ. Sci. Technol. 37 (2003), pp. 673680. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-lVersion=0&_userid=2139813&md5=bea2f2745c756b9134853fc1b400256c

Page 10 of 18

Bej et al., 1990 A.K. Bej, R.J. Steffan, J. DiCesare, L. Haff and R.M. Atlas, Detection of coliform bacteria in water by polymerase chain reaction and gene probes, Appl. Environ. Microbiol. 56 (1990), pp. 307314. Abstract + References in Scopus | Cited By in Scopus Bej et al., 1991 A.K. Bej, S.C. McCarty and R.M. Atlas, Detection of coliform bacteria and Escherichia coli by multiple polymerase chain reaction: comparison with defined substrate and plating methods for water quality monitoring, Appl. Environ. Microbiol. 57 (1991), pp. 24292432. Abstract + References in Scopus | Cited By in Scopus Bernhard and Field, 2000a A.E. Bernhard and K.G. Field, Identification of nonpoint sources of fecal pollution in coastal waters by using host-specific 16S ribosomal DNA genetic markers from fecal anaerobes, Appl. Environ. Microbiol. 66 (2000), pp. 15871594. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Bernhard and Field, 2000b A.E. Bernhard and K.G. Field, A PCR assay to discriminate human and ruminant feces on the basis of host differences in Bacteroides Prevotella genes encoding 16S rRNA, Appl. Environ. Microbiol. 66 (2000), pp. 45714574. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Blackwood et al., 2003 C.B. Blackwood, T. Marsh, S.-H. Kim and E.A. Paul, Terminal restriction fragment length polymorphism data analysis for quantitative comparison of microbial communities, Appl. Environ. Microbiol. 69 (2003), pp. 926932. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Bonjoch et al., 2004 X. Bonjoch, E. Balleste and A.R. Blanch, Multiplex PCR with 16S rRNA gene-targeted primers of Bifidobacterium spp. to identify sources of fecal pollution, Appl. Environ. Microbiol. 70 (2004), pp. 31713175. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Borrego et al., 1990 J. Borrego, R. Cornax, M.A. Morinigo, E. Martinez-Manzanares and P. Romero, Coliphages as an indicator of faecal pollution in water. Their survival and productive infectivity in natural aquatic environments, Water Res. 24 (1990), pp. 111116. Abstract | Abstract + References | PDF (428 K) | Abstract + References in Scopus | Cited By in Scopus Borrego et al., 1987 J.J. Borrego, M.A. Morinigo, A. de Vicente, R. Cornax and P. Romero, Coliphages as an indicator of faecal pollution in water. Its relationship with indicator and pathogenic microorganisms, Water Res. 21 (1987), pp. 14731480. Abstract | Abstract + References | PDF (682 K) | Abstract + References in Scopus | Cited By in Scopus Burtscher and Wuertz, 2003 C. Burtscher and S. Wuertz, Evaluation of the use of PCR and reverse transcriptase PCR for detection of pathogenic bacteria in biosolids from anaerobic digestors and aerobic composters, Appl. Environ. Microbiol. 69 (2003), pp. 46184627. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Carrillo et al., 1985 M. Carrillo, E. Estrada and T.C. Hazen, Survival and enumeration of the fecal indicator Bifidobacterium adolescentis and E. coli in tropical rain forest watershed, Appl. Environ. Microbiol. 50 (1985), pp. 468476. Abstract + References in Scopus | Cited By in Scopus Cornax et al., 1991 R. Cornax, M.A. Morinigo, M.C. Balebona, D. Castro and J. Borrego, Significance of several bacteriophage groups as indicators of sewage pollution in marine waters, Water Res. 25 (1991), pp. 673678. Abstract | Abstract + References | PDF (520 K) | Abstract + References in Scopus | Cited By in Scopus Chizhikov et al., 2001 V. Chizhikov, A. Rasooly, K. Chumakov and D.D. Levy, Microarray analysis of microbial virulence factors, Appl. Environ. Microbiol. 67 (2001), pp. 32583263. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Chizhikov et al., 2002 V. Chizhikov, M. Wagner, A. Ivshina, Y. Hoshino, A.Z. Kapikian and K. Chumakov, Detection and genotyping of human group A rotaviruses by oligonucleotide microarray hybridization, J. Clin. Microbiol. 40 (2002), pp. 23982407. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Cho and Tiedji, 2002 J.-C. Cho and J.M. Tiedji, Quantitative detection of microbial genes by using DNA microarrays, Appl. Environ. Microbiol. 68 (2002), pp. 14251430. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Chung and Sobsey, 1993 H. Chung and M.D. Sobsey, Comparative survival of indicator viruses and enteric viruses in seawater and sediments, Water Sci. Technol. 27 (1993), pp. 425428. Abstract + References in Scopus | Cited By in Scopus Davies et al., 1995 C.M. Davies, J.A.H. Long, M. Donald and N.J. Ashbolt, Survival of fecal microorganisms in marine and freshwater sediments, Appl. Environ. Microbiol. 61 (1995), pp. 18881896. Abstract + References in Scopus | Cited By in Scopus Desmarais et al., 2002 T.R. Desmarais, H.M. Solo-Gabriele and C.J. Palmer, Influence of soil on fecal indicator organisms in a tidally influenced subtropical environment,Appl.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-lVersion=0&_userid=2139813&md5=bea2f2745c756b9134853fc1b400256c Page 11 of 18
Environ. Microbiol. 68 (2002), pp. 11651172. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Dick and Field, 2004 L.K. Dick and K.G. Field, Rapid estimation of numbers of fecal Bacteroidetes by use of a quantitative PCR assay for 16 S rRNA genes, Appl. Environ. Microbiol. 70 (2004), pp. 6955697. Dombek et al., 2000 P.E. Dombek, L.K. Jonhson, S.T. Zimmerley and M.J. Sadowsky, Use of repetitive DNA sequences and the PCR to differentiate Escherichia coli isolates from human and animal sources, Appl. Environ. Microbiol. 66 (2000), pp. 25722577. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Dutka et al., 1974 B.J. Dutka, A.S.Y. Chau and J. Coburn, Relationship between bacterial indicators of water pollution and fecal sterols, Water Res. 8 (1974), pp. 10471055. Abstract | Abstract + References | PDF (552 K) | Abstract + References in Scopus | Cited By in Scopus Dutka et al., 1987 B.J. Dutka, A.E. Shaarawi and M.T. Martins, North and south american studies on the potential of coliphage as a water quality indicator, Water Res. 21 (1987), pp. 11271134. Abstract | Abstract + References | PDF (627 K) | Abstract + References in Scopus | Cited By in Scopus Fawell, 2003 J. Fawell, A perspective on drinking water standards in different parts of the world. In: Y. Watanabe and N. Funamizu, Editors, Water Resources and Water Supply in the 21st Century, Hokkaido University Press, Sapporo, Japan (2003), pp. 4959. Fey et al., 2004 A. Fey, S. Eichler, S. Flavier, R. Christen, M.G. Hofle and C.A. Guzman, Establishment of a real-time PCR-based approach for accurate quantification of bacterial RNA targets in water, using Salmonella as a model organism, Appl. Environ. Microbiol. 70 (2004), pp. 36183623. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Fiksdal et al., 1985 L. Fiksdal, J.S. Maki, S.J. LaCroix and J.T. Staley, Survival and detection of Bactreoides spp., prospective indicator bacteria, Appl. Environ. Microbiol. 49 (1985), pp. 148150. Abstract + References in Scopus | Cited By in Scopus Field et al., 2003 K.G. Field, A.E. Bernhard and T.J. Brodeur, Molecular approaches to microbiological monitoring: fecal source detection, Environmental Monitoring and Assessment 81 (2003), pp. 313326. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Figueras et al., 1996 M.J. Figueras, I. Inza, F.L. Polo, M.T. Feliu and J. Guarro, A fast method for the confirmation of fecal streptococci from M-enterococcus medium, Appl. Environ. Microbiol. 62 (1996), pp. 21772178. Abstract + References in Scopus | Cited By in Scopus Fout et al., 2003 G.S. Fout, B.C. Martinson, M.W.N. Moyer and D.R. Dahling, A multiplex reverse transcription-PCR method for detection of human enteric viruses in groundwater, Appl. Environ. Microbiol. 69 (2003), pp. 31583164. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Franck et al., 1998 S.M. Franck, B.T. Bosworth and H.W. Moon, Multiplex PCR for enteropathogenic, attaching and effacing, and shiga-toxin-producing E. coli strains from calves, J. Clin. Microbiol. 36 (1998), pp. 17951797. Abstract + References in Scopus | Cited By in Scopus Franks et al., 1998 A.H. Franks, H.J.M. Harmsen, G.C. Raangs, G.J. Jansen, F. Schut and G.W. Welling, Variation of bacterial populations in human feces measured by fluorescent in situ hybridization with group-specific 16S rRNA-targeted oligonucleotide probes, Appl. Environ. Microbiol. 64 (1998), pp. 33363345. Abstract + References in Scopus | Cited By in Scopus Fukushima et al., 2002 M. Fukushima, K. Kakinuma and R. Kawaguchi, Phylogenetic analysis of Salmonella, Shigella, and E. coli strains on the basis of the gyrB gene sequence, J. Clin. Microbiol. 40 (2002), pp. 27792785. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Gibson et al., 1996 U.E.M. Gibson, C.A. Heid and P.M. Williams, A novel method for real time quantitative RT-PCR, Genome Methods 6 (1996), pp. 9951001. Abstract + References in Scopus | Cited By in Scopus Guan et al., 2002 S. Guan, R. Xu, S. Chen, J. Odumeru and C. Gyles, Development of a procedure for discriminating among E. coli isolates form animal and human sources, Appl. Environ. Microbiol. 68 (2002), pp. 26902698. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Haramoto et al., 2004 E. Haramoto, H. Katayama and S. Ohgaki, Detection of noroviruses in tap water in Japan by means of a new method for concentrating enteric viruses in large

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-lVersion=0&_userid=2139813&md5=bea2f2745c756b9134853fc1b400256c Page 12 of 18
volumes of freshwater, Appl. Environ. Microbiol. 70 (2004), pp. 21542160. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Havelaar and Pot-Hogeboom, 1988 A.H. Havelaar and W.M. Pot-Hogeboom, F-specific RNA-bacteriophages as model viruses in water hygiene: ecological aspects, Water Sci. Technol. 20 (1988), pp. 399407. Abstract + References in Scopus | Cited By in Scopus Head et al., 1998 I.M. Head, J.R. Saunders and R.W. Pickup, Microbial evolution, diversity, and ecology: a decade of ribosomal RNA analysis of uncultivated microorganisms, Microbial Ecology 35 (1998), pp. 121. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Heid et al., 1996 C.A. Heid, J. Stevens, K.J. Livak and P.M. Williams, Real time quantitative PCR, Genome Methods 6 (1996), pp. 986994. Abstract + References in Scopus | Cited By in Scopus Hein et al., 2001 I. Hein, A. Lehner, P. Rieck, K. Klein, E. Brandl and M. Wagner, Comparison of different approaches to quantify Staphylococcus aureus cells by real-time quantitative PCR and application of this technique for examination of cheese, Appl. Environ. Microbiol. 67 (2001), pp. 31223126. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Horman et al., 2004 A. Horman, R. Rimhanen-Finne, L. Maunula, C.-H. von Bonsdorff, N. Torvela, A. Heikinheimo and M.-L. Hanninen, Campylobacter spp., Giardia spp., Cryptosporidium spp., Noroviruses, and indicator organisms in surface water in southwestern Finland, 20002001, Appl. Environ. Microbiol. 70 (2004), pp. 8795. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Huijsdens et al., 2002 X.W. Huijsdens, R.K. Linskens, M. Mak, S.G.M. Meuwissen, C.M.J.E. Vandenbroucke-Grauls and P.H.M. Savelkoul, Quantification of bacterial adherent to gastrointestinal mucosa by real-time PCR, J. Clin. Microbiol. 40 (2002), pp. 44234427. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Hurst et al., 2002 C.J. Hurst, R.L. Crawford, G.R. Knudsen, M.J. McInerney and L.D. Stetzenbach, Manual of Environmental Microbiology (second ed), ASM Press, Washington, DC (2002). IAWPRC Study Group on Health Related Water Microbiology, 1991 IAWPRC Study Group on Health Related Water Microbiology, Bacteriophages as model viruses in water quality control, Water Res. 25 (1991), pp. 529545. Ibekwe et al., 2002 A.M. Ibekwe, P.M. Watt, C.M. Grieve, V.K. Sharma and S.R. Lyons, Multiplex fluorogenic real-time PCR for detection and quantification of Escherichia coli O157:H7 in dairy wastewater wetlands, Appl. Environ. Microbiol. 68 (2002), pp. 4853 4862. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Isobe et al., 2002 K.O. Isobe, M. Tarao, M.P. Zakaria, N.H. Chiem, L.Y. Minh and H. Takada, Quantitative application of fecal sterols using gas chromatography mass spectrometry to investigate fecal pollution in tropical waters: western Malaysia and Mekong Delta, Vietnam, Environ. Sci. Technol. 36 (2002), pp. 44974507. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Isobe et al., 2004 K.O. Isobe, M. Tarao, N.H. Chiem, L.Y. Minh and H. Takada, Effect of environmental factors on the relationship between concentrations of coprostanol and fecal indicator bacteria in tropical (Mekong Delta) and temperate (Tokyo) freshwaters, Appl. Environ. Microbiol. 70 (2004), pp. 814821. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Jofre et al., 1986 J. Jofre, A. Bosch, F. Lucena, R. Girones and C. Tartera, Evaluation of Bacteroides fragilis bacteriophages as indicators of the virulogical quality of water, Water Sci. Technol. 18 (1986), pp. 167173. Abstract + References in Scopus | Cited By in Scopus Kinzelman et al., 2003 J. Kinzelman, C. Ng, E. Lackson, S. Gradus and R. Bagley, Enterococci as indicators of lake Michigan recreational water quality: comparison of two methodologies and their impacts on public health regulatory events, Appl. Environ. Microbiol. 69 (2003), pp. 9296. Full Text via CrossRef Kong et al., 2002 R.Y.C. Kong, S.K.Y. Lee, T.W.F. Law, S.H.W. Law and R.S.S. Wu, Rapid detection of six types of bacterial pathogens in marine waters by multiplex PCR, Water Res. 36 (2002), pp. 28022812. SummaryPlus | Full Text + Links | PDF (251 K) | Abstract + References in Scopus | Cited By in Scopus Kott et al., 1974 Y. Kott, N. Roze, S. Sperber and N. Betzer, Bacteriophages as viral pollution indicators, Water Res. 8 (1974), pp. 165171. Abstract | Abstract + References | PDF (450 K) | Abstract + References in Scopus | Cited By in Scopus Kreader, 1995 C.A. Kreader, Design and evaluation of Bacteroides DNA probes for the specific detection of human fecal pollution, Appl. Environ. Microbiol. 61 (1995), pp. 1171

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-lVersion=0&_userid=2139813&md5=bea2f2745c756b9134853fc1b400256c Page 13 of 18
1179. Abstract + References in Scopus | Cited By in Scopus Kreader, 1996 C.A. Kreader, Relief of amplification inhibition in PCR with bovine serum albumin or T4 gene 32 protein, Appl. Environ. Microbiol. 62 (1996), pp. 11021106. Abstract + References in Scopus | Cited By in Scopus Kreader, 1998 C.A. Kreader, Persistence of PCR-detectable Bacteroides distasonis from human feces in river water, Appl. Environ. Microbiol. 64 (1998), pp. 41034105. Abstract + References in Scopus | Cited By in Scopus Kueh et al., 1995 C.S.W. Kueh, T.-Y. Tam, T. Lee, S.L. Wong, O.L. Lloyd, I.T.S. Yu, T.W. Wong, J.S. Tam and D.C.J. Basset, Epidemiological study of swimming-associated illnesses relating to bathing-beach water quality, Water Sci. Technol. 31 (1995), pp. 14. Abstract + References in Scopus | Cited By in Scopus Leclerc et al., 1996 H. Leclerc, L.A. Devriese and D.A.A. Mossel, Taxonomical changes in intestinal (faecal) enterococci and streptococci: consequences on their use as indicators of faecal contamination in drinking water, J. Appl. Bacteriol. 81 (1996), pp. 459466. Abstract + References in Scopus | Cited By in Scopus Leeming and Nichols, 1996 R. Leeming and P.D. Nichols, Concentrations of coprostanol that correspond to existing bacterial indicator guideline limits, Water Res. 30 (1996), pp. 29973006. SummaryPlus | Full Text + Links | PDF (950 K) | Abstract + References in Scopus | Cited By in Scopus Lemarchand and Lebaron, 2003 K. Lemarchand and P. Lebaron, Occurrence of Salmonella spp. and Cryptosporidium spp. in a French coastal watershed: relationship with fecal indicators, FEMS Microbiol. Lett. 218 (2003), pp. 203209. SummaryPlus | Full Text + Links | PDF (229 K) | Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Leung et al., 2004 K.T. Leung, R. Mackereth, Y.-C. Tien and E. Topp, A comparison of AFLP and ERIC-PCR analyses for discriminating Escherichia coli from cattle, pig and human sources, FEMS Microbial Ecol 47 (2004), pp. 111119. SummaryPlus | Full Text + Links | PDF (311 K) | Abstract + References in Scopus | Cited By in Scopus Lipp et al., 2001 E.K. Lipp, S.A. Farrah and J.B. Rose, Assessment and impact of microbial fecal pollution and human enteric pathogens in a coastal community, Mar. Pollut. Bull. 42 (2001), pp. 286293. SummaryPlus | Full Text + Links | PDF (668 K) | Abstract + References in Scopus | Cited By in Scopus Lofstrom et al., 2004 C. Lofstrom, R. Knutsson, C.E. Axelsson and P. Radstrom, Rapid detection of Salmonella spp. in animal feed samples by PCR after culture enrichment, Appl. Environ. Microbiol. 70 (2004), pp. 6975. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Loge et al., 2002 F.J. Loge, D.E. Thompson and D.R. Call, PCR detection of specific pathogens in water: a risk-based analysis, Environ. Sci. Technol. 36 (2002), pp. 27542759. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Lubeck et al., 2003a P.S. Lubeck, P. Wolffs, S.L.W. On, P. Ahrens, P. Radstrom and J. Hoorfar, Toward an international standards for PCR-based detection of food-borne thermotolerant Campylobacters: assay development and analytical validation, Appl. Environ. Microbiol. 69 (2003), pp. 56645669. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Lubeck et al., 2003b P.S. Lubeck, N. Cook, M. Wagner, P. Fach and J. Hoorfar, Toward an international standard for PCR-based detection of food-borne thermotolerant Campylobacters: validation in a multicenter collaborative trial, Appl. Environ. Microbiol. 69 (2003), pp. 56705672. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Macy, 1979 J. Macy, The biology of gastrointestinal bacteroides, Annu. Rev. Microbiol. 33 (1979), pp. 561594. Abstract + References in Scopus | Cited By in Scopus Malorny et al., 2003 B. Malorny, J. Hoorfar, C. Bunge and R. Helmuth, Multicenter validation of the analytical accuracy of Salmonella PCR: towards an international standards, Appl. Environ. Microbiol. 69 (2003), pp. 290296. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Malinen et al., 2003 E. Malinen, A. Kassinen, T. Rinttila and A. Palva, Comparison of realtime PCR with SYBR Green 1 or 5 -nuclease assays and dot-blot hybridization with rDNAtargeted oligonucleotide probes in quantification of selected faecal bacteria, Microbiology 149 (2003), pp. 269277. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Matsuki et al., 2004 T. Matsuki, K. Watanabe, J. Fujimoto, Y. Kado, T. Takada, K. Matsumoto and R. Tanaka, Quantitative PCR with 16S rRNA-gene-targeted specieshttp://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-lVersion=0&_userid=2139813&md5=bea2f2745c756b9134853fc1b400256c Page 14 of 18

specific primers for analysis of human intestinal bifidobacteria, Appl. Environ. Microbiol. 70 (2004), pp. 167173. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Matsuki et al., 2002 T. Matsuki, K. Watanabe, J. Fujimoto, Y. Miyamoto, T. Takada, K. Matsumoto, H. Oyaizu and R. Tanaka, Development of 16S rRNA-gene-targeted groupspecific primers for the detection and identification of predominant bacteria in human feces, Appl. Environ. Microbiol. 68 (2002), pp. 54455451. Abstract + References in Scopus | Cited By in Scopus Maus and Ingham, 2003 J.E. Maus and S.C. Ingham, Employment of stressful conditions during culture production to enhance subsequent cold- and acid-tolerance of bifidobacteria, Journal of Applied Microbiology 95 (2003), pp. 146154. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus McFeters et al., 1974 G.A. McFeters, G.K. Bissonnette, J.J. Jezeski, C.A. Thomson and D.G. Stuart, Comparative survival of indicator bacteria and enteric pathogens in well water, Appl. Environ. Microbiol. 27 (1974), pp. 823829. Abstract + References in Scopus | Cited By in Scopus McFeters, 1990 G.A. McFeters, Drinking Water Microbiology: Progress and Recent Developments, Springer, New York (1990). Medema et al., 1997 G.J. Medema, M. Bahar and F.M. Schets, Survival of Cryptosporidium parvum, of Escherichia coli, faecal enterococci and Clostridium perfringens in river water: influence of temperature and autochthonous microorganisms, Water Sci. Technol. 35 (1997), pp. 249252. Abstract | Abstract + References in Scopus | Cited By in Scopus Morinigo et al., 1990 M.A. Morinigo, R. Cornax, M.A. Munoz, P. Romero and J.J. Borrego, Relationships between Salmonella spp. and indicator microorganisms in polluted natural waters, Water Res. 24 (1990), pp. 117120. Abstract | Abstract + References | PDF (358 K) | Abstract + References in Scopus | Cited By in Scopus Nagashima et al., 2003 K. Nagashima, T. Hisada, M. Sato and J. Mochizuki, Application of new primer-enzyme combinations to terminal restriction fragment length polymorphism profiling of bacterial populations in human feces, Appl. Environ. Microbiol. 69 (2003), pp. 12511262. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Nebra et al., 2003 Y. Nebra, X. Bonjoch and A.R. Blanch, Use of Bifidobacterium dentium as an indicator of the origin of fecal water pollution, Appl. Environ. Microbiol. 69 (2003), pp. 26512656. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Noble and Fuhrman, 2001 R.T. Noble and J.A. Fuhrman, Enteroviruses detected by reverse transcriptase polymerase chain reaction from the coastal waters of Santa Monica Bay, California: low correlation to bacterial indicator levels, Hydrobiologia 460 (2001), pp. 175 184. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Novga et al., 2000 H.K. Novga, K. Rudi, K. Naterstad, A. Holck and D. Lillehaug, Application of 5 -nuclease PCR for quantitative detection of Listeria monocytogenes in pure cultures, water, skim milk, and unpasteurized whole milk, Appl. Environ. Microbiol. 66 (2000), pp. 42664271. Okabe et al., 1999 S. Okabe, H. Satoh and Y. Watanabe, In situ analysis of nitrifying biofilms as determined by in situ hybridization and the use of microelectrodes, Appl. Environ. Microbiol. 65 (1999), pp. 31823191. Abstract + References in Scopus | Cited By in Scopus Ootsubo et al., 2002 M. Ootsubo, T. Shimizu, R. Tanaka, T. Sawabe, K. Tajima and Y. Ezura, Oligonucleotide probe for detecting Enterobacteriaceae by in situ hybridization, J. Appl. Microbiol. 93 (2002), pp. 6068. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Ootsubo et al., 2003 M. Ootsubo, T. Shimizu, R. Tanaka, T. Sawabe, K. Tajima, M. Yoshimizu, Y. Ezura, T. Ezaki and H. Oyaizu, Seven-hours fluorescence in situ hybridization technique for enumeration of Enterobacteriaceae in food and environmental samples, Journal of Applied Microbiology 94 (2003), pp. 19. Osawa et al., 1981 S. Osawa, K. Furuse and I. Watanabe, Distribution of ribonucleic acid coliphages in animals, Appl. Environ. Microbiol. 41 (1981), pp. 164168. Abstract + References in Scopus | Cited By in Scopus Ottson and Stenstrom, 2003 J. Ottson and T.A. Stenstrom, Faecal contamination of greywater and associated microbial risks, Water Res. 37 (2003), pp. 645655. Panicker et al., 2004 G. Panicker, M.L. Myers and A.K. Bej, Rapid detection of Vibrio vulnificus in shellfish and gulf of Mexico water by real-time PCR, Appl. Environ. Microbiol. 70 (2004), pp. 498507. Full Text via CrossRef | Abstract + References in Scopus | Cited

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-lVersion=0&_userid=2139813&md5=bea2f2745c756b9134853fc1b400256c Page 15 of 18
By in Scopus Parveen et al., 1999 S. Parveen, K.M. Portier, K. Robinson, L. Edmiston and M.L. Tamplin, Discriminant analysis of ribotype profiles of Escherichia coli for differentiating human and nonhuman sources of fecal pollution, Appl. Environ. Microbiol. 65 (1999), pp. 31423147. Abstract + References in Scopus | Cited By in Scopus Payment and Franco, 1993 P. Payment and E. Franco, Clostridium perfringens and somatic coliphages as indicators of the efficiency of drinking water treatment for viruses and protozoan cysts, Appl. Environ. Microbiol. 59 (1993), pp. 24182424. Abstract + References in Scopus | Cited By in Scopus Payment et al., 2000 P. Payment, A. Berte, M. Prvost, B. Mnard and B. Barbeau, Occurrence of pathogenic microorganisms in the Saint Lawrence River (Canada) and comparison of health risks for populations using it as their source of drinking water, Can. J. Microbiol. 46 (2000), pp. 565576. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Pernthaler and Amann, 2004 A. Pernthaler and R. Amann, Simultaneous fluorescent in situ hybridization of mRNA and rRNA in environmental bacteria, Appl. Environ. Microbiol. 70 (2004), pp. 54265433. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Polo et al., 1998 F. Polo, M.J. Figueras, I. Inza, J. Sala, J.M. Fleisher and J. Guarro, Relationship between presence of Salmonella and indicators of fecal pollution in aquatic habitats, FEMS Microbiology Letters 160 (1998), pp. 253256. SummaryPlus | Full Text + Links | PDF (144 K) | Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Resnick and Levin, 1981 I.G. Resnick and M.A. Levin, Assessment of bifidobacteria as indicator of human fecal pollution, Appl. Environ. Microbiol. 42 (1981), pp. 433438. Abstract + References in Scopus | Cited By in Scopus Rhodes and Kator, 1999 M.W. Rhodes and H. Kator, Sorbitol-fermenting bifidobacteria as indicators of diffuse human faecal pollution in estuarine watersheds, J. Appl. Microbiol. 87 (1999), pp. 528535. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Rolfe et al., 1977 R.D. Rolfe, D.J. Hentges, J.T. Barrett and B.J. Campbell, Oxygen tolerance of human intestinal anaerobes, Am. J. Clin. Nutr. 30 (1977), pp. 17621769. Abstract + References in Scopus | Cited By in Scopus Roll and Fujioka, 1997 B.M. Roll and R.S. Fujioka, Sources of faecal indicator bacteria in a brackish tropical stream and their impact on recreational water quality, Water Sci. Technol. 35 (1997), pp. 179186. Abstract | Abstract + References in Scopus | Cited By in Scopus Rozen and Belkin, 2001 Y. Rozen and S. Belkin, Survival of enteric bacteria in seawater, FEMS Microbiology Reviews 25 (2001), pp. 513529. SummaryPlus | Full Text + Links | PDF (248 K) | Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Savichtcheva et al., 2005 O. Savichtcheva, N. Okayama, T. Ito and S. Okabe, Application of a direct fluorescent-based live/dead staining combined with fluorescent in situ hybridization for assessment of survival rate of Bacteroides spp. in oxygenated water, Biotechnol. Bioeng. 92 (2005), pp. 356363. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Scott et al., 2002 T. Scott, J.B. Rose, T.M. Jenkins, S.R. Farrah and J. Lukasik, Microbial source tracking: current methodology and future directions, Appl. Environ. Microbiol. 68 (2002), pp. 57965803. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Seurinck et al., 2003 S. Seurinck, W. Verstraete and S.D. Siciliano, Use of 16S-23S rRNA intergenic spacer region PCR and repetitive extragenic palindromic PCR analyses of Escherichia coli isolates to identify nonpoint fecal sources, Appl. Environ. Microbiol. 69 (2003), pp. 49424950. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Seurinck et al., 2005 S. Seurinck, T. Defoirdt, W. Verstraete and A.D. Siciliano, Detection and quantification of the human-specific HF183 Bacteroides 16S rRNA genetic marker with real-time PCR for assessment of human faecal pollution in freshwaters, Environmental Microbiology 7 (2005), pp. 249259. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Simpson et al., 2002 J.M. Simpson, J.W. Santo Domingo and D.J. Reasoner, Microbial source tracking: state of the science, Environ. Sci. Technol. 24 (2002), pp. 52795288. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus

Page 16 of 18

Simpson et al., 2004 J.M. Simpson, J.W. Santo Domingo and D.J. Reasoner, Assessment of equine fecal contamination: the search for alternative bacterial source-tracking targets, FEMS Microbiol. Ecol. 47 (2004), pp. 6575. SummaryPlus | Full Text + Links | PDF (1195 K) | Abstract + References in Scopus | Cited By in Scopus Singh et al., 2001 D.V. Singh, M.H. Matte, G.R. Matte, S. Jiang, F. Sabeena, B.N. Shukla, S.C. Sanyal, A. Huq and R.R. Colwell, Molecular analysis of Vibrio cholerae O1, O139, non-O1, and non-O139 strains: clonal relationships between clinical and environmental isolates, Appl. Environ. Microbiol. 67 (2001), pp. 910921. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Sinton et al., 1993 L.W. Sinton, A.M. Donnison and C.M. Hastie, Faecal streptococci as faecal pollution indicators: a review. Part 1: taxonomy and enumeration, New Zealand J. Mar. FreshWater Res. 27 (1993), pp. 101115. Sinton et al., 2002 L.W. Sinton, C.H. Hall, F.A. Lynch and R.J. Davies-Colley, Sunlight inactivation of fecal indicator bacteria and bacteriophages from waste stabilization pond effluent in fresh and saline waters, Appl. Environ. Microbiol. 68 (2002), pp. 11221131. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Solo-Gabriele et al., 2000 H.M. Solo-Gabriele, M.A. Wolfert, T.R. Desmarais and C.J. Palmer, Sources of E. coli in a coastal subtropical environment, Appl. Environ. Microbiol. 66 (2000), pp. 230237. Abstract + References in Scopus | Cited By in Scopus Sorensen et al., 1989 D.L. Sorensen, S.G. Eberl and R.A. Dicksa, Clostridium perfringens as a point source indicator in non-point polluted streams, Water Res. 23 (1989), pp. 191 197. Abstract | Abstract + References | PDF (571 K) | Abstract + References in Scopus | Cited By in Scopus Stender et al., 2001 H. Stender, A.J. Broomer, K.O.H. Perry-OKeefe, J.J. Hyldig-Nielsen, A. Sage and J. Coull, Rapid detection, identification, and enumeration of E. coli cells in municipal water by chemiluminescent in situ hybridization, Appl. Environ. Microbiol. 67 (2001), pp. 142147. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Tartera and Jofre, 1987 C. Tartera and J. Jofre, Bacteriophages active against Bacteroides fragilis in sewage-polluted waters, Appl. Environ. Microbiol. 53 (1987), pp. 16321637. Abstract + References in Scopus | Cited By in Scopus Tartera et al., 1988 C. Tartera, J. Jofre and F. Lucena, Relationship between numbers of enteroviruses and bacteriophages infecting Bacteroides fragilis in different environmental samples, Environ. Technol. Lett. 9 (1988), pp. 407410. Abstract + References in Scopus | Cited By in Scopus Tartera et al., 1989 C. Tartera, F. Lucena and J. Jofre, Human origin of Bacteroides fragilis bacteriophages present in the environment, Appl. Environ. Microbiol. 55 (1989), pp. 2696 2701. Abstract + References in Scopus | Cited By in Scopus Van Dolsen and Geldreich, 1971 D.J. Van Dolsen and E.E. Geldreich, Relationships of salmonellae to fecal coliforms in bottom sediments, Water Res. 5 (1971), pp. 10791087. Volokhov et al., 2002 D. Volokhov, A. Rasooly, K. Chumakov and V. Chizhikov, Identification of Listeria species by microarray-based assay, J. Clin. Microbiol. 40 (2002), pp. 47204728. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Vora et al., 2004 G.J. Vora, C.E. Meador, D.A. Stenger and J.D. Andreadis, Nucleic acid amplification strategies for DNA microarray-based pathogen detection, Appl. Environ. Microbiol. 70 (2004), pp. 30473054. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Wellinghausen et al., 2001 N. Wellinghausen, C. Frost and R. Marre, Detection of Legionellae in hospital water samples by quantitative real-time LightCycler PCR, Appl. Environ. Microbiol. 67 (2001), pp. 39853993. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Winfield and Groisman, 2003 M.D. Winfield and E.A. Groisman, Role of nonhost environment in the lifestyle of Salmonella and E. coli, Appl. Environ. Microbiol. 69 (2003), pp. 36873694. Full Text via CrossRef | Abstract + References in Scopus | Cited By in Scopus Wood et al., 1998 J. Wood, K. Scott, G. Avgustin, C.J. Newbold and H.J. Flint, Estimation of the relative abundance of different Bacteroides Prevotella ribotypes in gut samples by restriction enzyme profiling of PCR-amplified 16S rRNA gene sequences, Appl. Environ. Microbiol. 64 (1998), pp. 36833689. Abstract + References in Scopus | Cited By in Scopus Xiao et al., 2001 L. Xiao, A. Singh, J. Limor, T.K. Graczyk, S. Gradus and A. Lal, Molecular characterization of Cryptosporidium oocysts in samples of raw water and