The optimization and application of two direct viable count methods for bacteria in distributed drinking water

Coallier, Josée; Prévost, Michèle; Rompré, A.; Duchesne, Daniel

doi:10.1139/m94-132

Cited by 53 publications

(42 citation statements)

References 20 publications

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“…Joux and LeBaron used an antibiotic cocktail to overcome this difficulty and then demonstrated the effectiveness of their improved DVC procedure (12). Second, it is often difficult to discriminate between elongated (fattened) cells and cells which are not elongated or fattened (6). Elongated cells may be smaller than the population average and may be missed during a count.…”

mentioning

confidence: 99%

Improved Direct Viable Count Procedure for Quantitative Estimation of Bacterial Viability in Freshwater Environments

Yokomaku

Yamaguchi

Nasu

2000

Appl Environ Microbiol

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confidence: 99%

Improved Direct Viable Count Procedure for Quantitative Estimation of Bacterial Viability in Freshwater Environments

Yokomaku

Yamaguchi

Nasu

2000

Appl Environ Microbiol

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“…The choice of the viability parameters in this study was based on the review of previous studies [21], [25], [27], [28] which described that the respiratory activity (CTC), substrate responsiveness (DVC assay) and cultivability were more direct methods for cell viability.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Chlorination on Escherichia Coli Viability in Drinking Water

Denisova

Mežule

Juhna

2014

Material Science and Applied Chemistry

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-The assessment of drinking water disinfection efficiency traditionally involves the estimation of faecal indicator inactivation rates in the form of reduction of cultivable counts. Widely described, viable but noncultivable (VBNC) state as a form of bacterial survival strategy in oligotrophic conditions is not considered in these estimations. The aim of the present research is to assess the effect of free chlorine disinfection on faecal indicator Escherichia coli in order to study the succession of cellular alterations in response to chlorine exposure. To determine the inactivation rates, cell ability to form colonies, ability to divide as such and metabolic activity have studied. 0.064 mg/L min -1 free chlorine has been needed to obtain 99 % inactivation of cultivable counts; however, 5 till 200 times higher disinfectant dose x contact time has been required to reduce cell ability to divide and metabolic activity, respectively. The results have shown that to determine correct drinking water disinfectant doses multiple cell viability parameters should be analyzed.

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“…This redox activity can be detected directly by epifluorescence microscopy and flow cytometry as well as spectrophotometry. The CTC reduction method has been used to detect viable or respiring cells of microorganisms in purified and drinking water 10,23,31,32) , groundwater 17) , aquatic ecosystems 9,14,26,28,[34][35][36][37][38] , sediment 16,28) , soil 7,33,45,46) and bioreactors 11) . This method also has been applied to wastewater and activated sludge systems 27,44) .…”

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confidence: 99%

An Improved Redox Dye-Staining Method Using 5-Cyano-2,3-Ditoryl Tetrazolium Chloride for Detection of Metabolically Active Bacteria in Activated Sludge

Yoshida

Hiraishi

2004

Microb. Environ.

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A fluorochrome-staining method using 5-cyano-2,3-ditoryl tetrazolium chloride (CTC) was improved to enhance the sensitivity of detection of metabolically active bacteria in activated sludge. The highest efficiency of CTC staining was obtained with 6 mM CTC in MOPS buffer at pH 6.5. CTC staining efficiency was also increased by adding a substrate mixture (0.05% peptone, 0.05% yeast extract and 1 mM glucose), Meldola's Blue as an electron transfer mediator and KCN. The bacterial counts detected by the CTC staining method thus improved accounted for 41-76% of the total counts in activated sludge with the average value being 54%. This value was approximately two-fold higher than those obtained by the traditional CTC staining assay which has been performed in phosphate buffer or phosphate-buffered saline without any addition of external substrate or electron transfer mediator. There was a high positive correlation between CTC-stained direct counts and the plate counts of aerobic chemoorganotrophic bacteria or viable cell counts measured using a LIVE/DEAD BacLight Bacterial Viability kit. The viable population in the activated sludges as measured by BacLight staining and plate counting accounted for 73±7.6% and 8.7±4.7% of the total population, respectively. These data suggested that most of the "viable but nonculturable" bacteria (i.e., BacLight-positive but unculturable population) potentially existing in the sludge system were so metabolically active as to be detectable by the improved CTC staining method.

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The optimization and application of two direct viable count methods for bacteria in distributed drinking water

Cited by 53 publications

References 20 publications

Improved Direct Viable Count Procedure for Quantitative Estimation of Bacterial Viability in Freshwater Environments

Improved Direct Viable Count Procedure for Quantitative Estimation of Bacterial Viability in Freshwater Environments

The Effect of Chlorination on Escherichia Coli Viability in Drinking Water

An Improved Redox Dye-Staining Method Using 5-Cyano-2,3-Ditoryl Tetrazolium Chloride for Detection of Metabolically Active Bacteria in Activated Sludge

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