New methods to assess bacterial injury in water

Zaske, S K; Dockins, William S.; Schillinger, John E.; McFeters, Gordon A.

doi:10.1128/aem.39.3.656-658.1980

Cited by 21 publications

(14 citation statements)

References 5 publications

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“…The present study has demonstrated that a substantial proportion of E. coli cells subjected to either UVA or simulated sunlight become sublethally damaged, reaching a point where they can no longer form colonies in air on an agar-based medium. Following the approach of Zaske et al (1980), the relative percentage of such injured cells can be calculated by comparing the aerobic plate count for unsupplemented medium (uninjured cells) with the equivalent count for anaerobic, pyruvate-supplemented medium (injured plus uninjured cells). On this basis, c. 99% of the cells of E. coli NCTC 8912 subjected to simulated sunlight for a period of 6 h were sublethally damaged, being capable of forming colonies only under anaerobic, pyruvate-supplemented conditions and not under aerobic conditions (Fig.…”

Section: Discussionmentioning

confidence: 99%

Oxygen and photoinactivation ofEscherichia coliin UVA and sunlight

Khaengraeng

Reed

2005

Journal of Applied Microbiology

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Aims: To establish the influence of oxygen on Escherichia coli before, during and after exposure to UVA or simulated sunlight. Methods and Results: Bacterial suspensions were exposed either to UVA or simulated sunlight. Conventional aerobic plate counts of illuminated cell suspensions were consistently lower than those obtained under conditions where reactive oxygen species (ROS) were neutralized, either (i) by the addition of the peroxide scavenger sodium pyruvate (0AE05% w/v) to the medium with subsequent incubation in an anaerobic jar or (ii) by culturing on a prereduced medium within an anaerobic cabinet, indicating that a substantial proportion of such cells are sublethally injured. While the presence of oxygen during the growth period resulted in a greater resistance of aerobically grown cells to simulated sunlight compared with their anaerobic counterparts, the extent of inactivation during illumination was directly related to the dissolved oxygen content of the water. Conclusions:The results show that, at each stage, oxygen has a marked influence on the observed colony count. Significance and Impact of the Study: Overall, the results indicate that future studies of bacteria exposed to UVA or sunlight should consider the effects of oxygen at every stage in the procedure, and especially during enumeration, where the inhibitory effects of ROS must be neutralized in order to obtain a valid count. An investigation of the effects of ROS neutralization on the counts of faecal bacteria under field conditions in natural waters is now required to establish the significance of these finding to solar water treatment.

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Section: Discussionmentioning

confidence: 99%

Oxygen and photoinactivation ofEscherichia coliin UVA and sunlight

Khaengraeng

Reed

2005

Journal of Applied Microbiology

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“…The extent of chlorine-induced injury was determined from differential counts on tryptone lactose yeast extract (TLY) and TLYD (TLY with 0·1% deoxycholate) agar plates (Zaske et al 1980). Both types of plates were inoculated, incubated, and counted as described above.…”

Section: Viable Plate Counts and Injury Assessmentmentioning

confidence: 99%

The use of multiple indices of physiological activity to access viability in chlorine disinfectedEscherichia coliO157:H7

Lisle

Pyle

McFeters

1999

Letters in Applied Microbiology

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R S. 1999. A suite of fluorescent intracellular stains and probes was used, in conjunction with viable plate counts, to assess the effect of chlorine disinfection on membrane potential (rhodamine 123; Rh123 and bis-(1,3-dibutylbarbituric acid) trimethine oxonol; DiBAC 4 (3)), membrane integrity (LIVE/DEAD BacLight kit), respiratory activity (5-cyano-2,3-ditolyl tetrazolium chloride; CTC) and substrate responsiveness (direct viable counts; DVC) in the commensal pathogen Escherichia coli O157:H7. After a 5 min exposure to the disinfectant, physiological indices were affected in the following order: viable plate counts × substrate responsiveness × membrane potential × respiratory activity × membrane integrity. In situ assessment of physiological activity by examining multiple targets, as demonstrated in this study, permits a more comprehensive determination of the site and extent of injury in bacterial cells following sublethal disinfection with chlorine. This approach to assessing altered bacterial physiology has application in various fields where detection of stressed bacteria is of interest.

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“…Flint (1987) showed that in the absence of other bacteria, i.e. in the absence of competitors, in sterile autoclaved river water E. coli could Discussion survive for up to 260 d, even at 2 5 T , without The factors which are considered most likely to any decline in numbers and without suffering affect the survival of non-indigenous bacteria in any of the apparent stress symptoms seen by others (Bissonnette et al 1975(Bissonnette et al , 1977Zaske et al 1980). As expected, the addition of a complex mixture of nutrients, in the form of synthetic sewage, to filtered-autoclaved lake water allowed the E. coli to increase in numbers in proportion to the amount of synthetic sewage added.…”

Section: N I T R O G E N a D D I T I O N Smentioning

confidence: 99%

The effects of nutrients on the survival of Escherichia coli in lake water

Lim

Flint

1989

Journal of Applied Bacteriology

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Escherichia coli was shown to survive without decline in viable counts for at least 12 d in filtered-autoclaved lake water. In unfiltered lake water there was a rapid decline in the viable count of E. coli. The addition of synthetic sewage to filtered-autoclaved lake water led to an increase in the viable count of E. coli at 15 degrees C and 37 degrees C and to an increase in the survival time of the E. coli in unfiltered water. The addition of phosphate and carbon sources (glucose, glycerol, succinate, acetate and lactose) did not significantly increase the survival time of E. coli in unfiltered water over the controls. The addition of ammonium sulphate and some amino acids (as nitrogen sources) to the unfiltered lake water did lead to an increase in the survival times for E. coli and this increase was proportional to the concentration of the added nitrogen source.

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New methods to assess bacterial injury in water

Abstract: Two methods are described for measurement of bacterial injury in water. Laboratory time preceding cell division measured with slide cultures and spheroplast formation after lysozyme treatment were accurate and rapid measurements of bacterial damage.

Cited by 21 publications

References 5 publications

Oxygen and photoinactivation ofEscherichia coliin UVA and sunlight

Oxygen and photoinactivation ofEscherichia coliin UVA and sunlight

The use of multiple indices of physiological activity to access viability in chlorine disinfectedEscherichia coliO157:H7

The effects of nutrients on the survival of Escherichia coli in lake water

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