摘要:

AbstractColiphages may be suitable alternative indicators of fecal pollution in natural waters. The relationship between coliphage and fecal coliform numbers may be expressed by log10transformed linear regression equations in surface waters (correlation coefficient,r2= 0.5872;p<0.001) and in well waters (r2= 0.4767;p<0.001). Using the American Public Health Association 919C single agar layer method, coliphages can be enumerated easily and at less cost and more rapidly than coliform enumeration methods. In adapting this test for use in a field test kit, however, further modifications and simplifications are required.The use of 2,3,5‐triphenyl tetrazolium chloride (TPTZ) to enhance plaque visibility while helpful, was not essential. Matched‐pairt‐test analysis showed no significant difference between the plaque numbers enumerated with or without TPTZ to help plaque visibility.TheEscherichia coliC host bacteria can be maintained either as a frozen preparation or dried on to paper disks with protective milk colloids. In the latter procedure, a resuscitation period of 18–24 h in broth at 30°C was found to be satisfactory in giving plaque numbers in the test that were not significantly different than when frozen host was used.A portable field kit has been designed to carry out a total of eight tests. The kit includes the media, the bacterial host, petri dishes, syringes, receptacles, and a camping gas cylinder. It measures 38 cm by 25.5 cm by 33.5 cm and weighs about 6.4 kg. Using the kit, the test procedure for a water sample can be carried out in unde

ISSN:0884-8181    

DOI:10.1002/tox.2540030503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractNowhere is the importance of accurate determination of recent human fecal contamination greater than in the tropics. The diversity of waterborne diseases and their severity is greatest in tropical environments. Since most of the countries in tropical climates are underdeveloped, with large populations that are undernourished, ill‐housed, with poor medical services, waterborne diseases may have a much greater effect on public health in the tropics than in temperate areas. Universally, tropical areas accept water maximum contaminant levels developed by temperate nations, despite the obvious differences in tropical climates. High densities of total and fecal coliform bacteria have been detected in pristine streams and in groundwater samples collected from many tropical parts of the world, even in epiphytic vegetation 10 m above ground in the rain forest of Puerto Rico. Nucleic acid (DNA) analyses ofEscherichia colifrom pristine tropical environs has indicated that they are identical to clinical isolates ofE. coli.Many tropical source waters have been shown to have enteric pathogens in the complete absence of coliforms. Diffusion chamber studies withE. coliat several tropical sites reveal that this bacterium can survive indefinitely in most freshwaters in Puerto Rico. An evaluation of methods for the enumeration of fecal coliforms showed that currently used media have poor reliability as a result of large numbers of false positive and false negative results when applied to tropical water samples. Total and fecal coliform bacteria are not reliable indicators of recent biological contamination of waters in tropical areas. Fecal streptococci and coliphages in tropical waters violate the same underlying assumptions of indicator assays as the coliforms. Anaerobic bacteria likeBifidobacteriumspp. andClostridium perfringensshow some promise in terms of survival, but not in ease of enumeration and media specificity. The best course at present lies in using current techniques for direct enumeration of pathogens by fluorescent staining and nucleic acid analysis, and developing tropical maximum contaminant levels for certain resistant pathogens in tropical water

ISSN:0884-8181    

DOI:10.1002/tox.2540030504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractMethods used to detectLegionellainclude direct fluorescent antibody stain, genetic probe, and culturing. Culturing is preferred for detectingLegionella pneumophila(Lp) in water; however, recovery rates are affected by treatment of water samples. Experiments with water‐containing Lp showed that (a) a water storage temperature of 4°C results in a slower decline in numbers of Lp as compared with 25, 35, and 45°C; (b) a water sample containing Lp and nonlegionellae microflora is appropriate for quality control of selective media used to isolateLegionellafrom environmental water specimens; and (c) acid treatment and concentration of water by filtration are effective techniques for isolating Lp from environmental water samples, but they do not yield 100% recovery of Lp ce

ISSN:0884-8181    

DOI:10.1002/tox.2540030505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractDrinking and other types of waters in three Latin American countries were sampled for the presence of enteroviruses, rotaviruses, and coliphages. Large volumes of water and sewage were concentrated using a positively charged filter for the detection of enteric viruses. Statistical analyses indicated no correlation between the presence or absence of fecal coliforms, total coliforms, fecal streptococci, and viruses. Total coliforms and fecal streptococci were isolated in large numbers from pristine tropical rain forest streams, but no enteric viruses were detected in any of the same samples. All streams contaminated with sewage contained enteric viruses and high levels of indicator bacteria. These results indicate that at the present time there is no reliable indicator of the presence of viruses in waters. The presence of coliphages in waters seemed associated with fecal contamination. The large numbers of fecal streptococci and coliforms (both fecal and total) present in the waters sampled may not necessarily indicate that these waters are contaminated with fecal waste.

ISSN:0884-8181    

DOI:10.1002/tox.2540030506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractPeptide toxins from the cyanobacteriaMicrocystic aeruginosa, Oscillatoria agardhii, Nodularia spumigena, andAnabaena flos‐aquaewere isolated. Of these, only the cyclic peptide ofMicrocystishas been characterized structurally and toxicologically in detail. Preliminary studies of the other peptide toxins have indicated that they may be structurally related to the toxins ofMicrocystis.The morphological and ultrastructural effects of these toxins were studied using freshly isolated hepatocytes. The toxins caused identical morphological alterations in the hepatocytes. Numerous surface swellings appeared on the cell surface and finally the normal cell morphology was totally disrupted. During this process, however, the viability of the cells was not affected. These results are viewed in the light of recent results showing that these toxins could exhibit a specific interaction with the actin part of the cytoskeleton. The overall results indicate that all four toxins may be toxicologically closely relate

ISSN:0884-8181    

DOI:10.1002/tox.2540030507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe associations between traditional coliform/fecal coliform indicator tests and coliphage, Presence/Absence (P/A), A‐1 broth, and H2S paper strip tests are evaluated for Peruvian waters.Drinking water samples showed that the P/A test was the most sensitive, producing the greatest number of positive results. In drinking water, in some of the samples, the only indicator organisms present were coliphage. The incidence of coliphage in these potable water supplies reflects the probability of human pathogenic viruses also surviving the treatment processes accorded those sample

ISSN:0884-8181    

DOI:10.1002/tox.2540030508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper summarizes the results obtained from an International Development Research Centre (IDRC), Ottawa, Canada, funded study to evaluate the potential of using coliphage as an indicator of water quality. Raw water sample data indicated that the A‐1 test combined with the coliphage test would make an excellent screening program for health hazards in these waters. The superiority of the Presence/Absence test for detecting microbial health hazards in potable water was readily shown, while the H2S paper strip technique was found to be equally efficient for testing potable waters as traditional coliform water quality indicator

ISSN:0884-8181    

DOI:10.1002/tox.2540030509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe increasing demand for potable water in Southeast Asia warrants the need for a simple, rapid, and economical water quality test that can be used by unskilled personnel to monitor potential fecal contamination of drinking water supplies. The coliphage test is expected to fulfill this need since many advantages can be attributed to this test.In order to evaluate the use of the coliphage test, an intensive study to correlate the results of the coliphage test with three other water quality tests—viz., conventional five‐tube most probable number (MPN) fermentation test, the A1 broth five‐tube MPN test, and the membrane filtration test—was carried out. At least 1000 water samples were examined over a 20‐month period. Results of the tests showed that there is a consistent relationship between coliphages and fecal coliforms in river water, pond water, well water and rainwater, in that coliphages are frequently found when fecal coliforms are detected. On the other hand, correlation analyses have also showed that in water sources that are shallow and turbid due to residual sediments, correlation between coliphages and fecal coliforms was less significant. Further analyses have also indicated that the factors that most affected the coliphage tests were turbidity, pH, and dissolved oxygen. In the process of evaluating the coliphage procedure, it was found that the test can be performed at ambient temperatures and results can be obtained after 6–8 h of

ISSN:0884-8181    

DOI:10.1002/tox.2540030510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe Autoanalysis Colilert (AC) test is a modification of the defined substrate technology designed to enumerate specific target microbe(s) from a mixture. All ingredients are present in the tube or vessel in powdered form. The AC test is simple to perform—a measured amount of water is added to test tubes (for the most probable number test) or vessel [Presence/Absence (P/A) test]. After incubation, the development of a yellow color is specific for total coliforms. Fluorescence in the same tube(s) is specific forEscherichia coli.No confirmatory or completed tests need be performed. A national United States evaluation covering all sources and processing of water was conducted. The AC test was compared to multiple tube fermentation (quantitative) and P/A (qualitative)Standard Methodsprocedures. Testing protocol was that of the U.S. Environmental Protection Agency's Environmental Monitoring and Support Laboratory for establishing equivalency between methods. The quantitative comparison showed that the AC test was slightly more sensitive than MTF. For two of five sites it was more precise; for the other three it was equal. For the qualitative P/A the AC andStandard Methodsanalysis agreed 94%. Specificity of the AC method was established by subculturing a species of total coliform orE. colifrom positives. The AC test was easy to use, can be performed by large and small utilities, and is less expensive than current methods. It can simultaneously, specifically enumerate total coliforms andE. coliwithout the need for confirmatory test

ISSN:0884-8181    

DOI:10.1002/tox.2540030511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractKlebsiellaoccurs widely in nature and is often present in surface waters used for human consumption or for recreational purposes. The organism can survive in water distribution systems despite chlorination. Many strains give rise to a positive fecal coliform test even when they are the only organisms present in the water sample. The public health significance ofKlebsiellain water is therefore an important concern. In the pastKlebsiellawas thought to be a significant pathogen in the community causing serious primary pneumonia, but such cases are now extremely rare. SeriousKlebsiellainfections are today commonly seen only in hospital patients whose resistance has been impaired by their primary disease condition. There is no evidence that waterborneKlebsiellaplay any significant part in the epidemiology of these hospital‐acquired infections.Klebsiellain water supplies should therefore not to be considered a hazard to human healt

ISSN:0884-8181    

DOI:10.1002/tox.2540030512

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY