Induction of Viable but Nonculturable (VBNC) state and the effect of multiple subculturing on the survival ofLegionella pneumophila strains in the presence of monochloramine

Türetgen, Irfan

doi:10.1007/bf03179460

Cited by 29 publications

(18 citation statements)

References 19 publications

(19 reference statements)

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“…The criterion used in our study describing the effect of ozone on cell viability is culturability (determination of colony counts). However, it was found by Turetgen (2008) that after monochloramine disinfection, Legionella pneumophila can completely lose their cultivability yet do not lose viability and therefore may be responsible for serious outbreaks that have occurred in countries across the world. Even after completely loosing cultivability, it is possible to find live cells in network water in the viable but nonculturable (VBNC) state (Turetgen 2008).…”

Section: Discussionmentioning

confidence: 99%

“…However, it was found by Turetgen (2008) that after monochloramine disinfection, Legionella pneumophila can completely lose their cultivability yet do not lose viability and therefore may be responsible for serious outbreaks that have occurred in countries across the world. Even after completely loosing cultivability, it is possible to find live cells in network water in the viable but nonculturable (VBNC) state (Turetgen 2008). The possibility of sublethal injury or the transition into a viable but nonculturable state after ozone treatment is not addressed experimentally in literature data.…”

Section: Discussionmentioning

confidence: 99%

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Effects of ozone on membrane permeability and ultrastructure in Pseudomonas aeruginosa

Zhang¹,

Wu²,

Zhang³

et al. 2011

Journal of Applied Microbiology

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Aims: To examine the mechanism of ozone‐induced damage to cytoplasmic membrane and cell ultrastructure of Pseudomonas aeruginosa ATCC27853. Methods and Results: Cell suspensions of Ps. aeruginosa ATCC27853 were treated with ozonated water. The leakages of cellular potassium (K+), magnesium (Mg2+) and adenosine triphosphate (ATP), determined by inductively coupled plasma/mass spectrometry (ICP/MS) and a commercial bioluminescence assay kit, were to assess ozone‐induced damage to the cytoplasmic membrane. Maximum leakages of K+ and Mg2+ were attained, respectively, at 0·53 mg l−1 ozone after 0·5 and 2 min with >99% inactivation of culturable bacteria, while that of ATP was achieved at 0·67 mg l−1 ozone after 1 min. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed that treated cells retained intact shapes and cytoplasm agglutinations and vacuoles occurred. Conclusions: Ozone inactivates Ps. aeruginosa ATCC27853 by the combined results of increased cytoplasmic membrane permeability and cytoplasm coagulation, rather than by severe membrane disruption and cell lysis. Significance and Impact of the Study: Pseudomonas aeruginosa is a common water‐related pathogen. These insights into the leakage of cytoplasmic components and ultrastructural changes provide evidence for the mechanisms of ozone‐mediated inactivation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effects of ozone on membrane permeability and ultrastructure in Pseudomonas aeruginosa

Zhang¹,

Wu²,

Zhang³

et al. 2011

Journal of Applied Microbiology

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“…The phenomenal 'viable but not culturable' (VBNC) state can also be induced in biofilm microenvironments. Transition into VBNC state is well-known for Legionella bacteria, especially in the presence of environmental stressors like disinfectants, pH alterations or changes in water temperature (Alleron et al, 2008;Türetgen, 2008). In distributed network systems, the VBNC bacteria might be a source of recontamination after disinfection is applied for Legionella control, even months after the end of the disinfection process.…”

Section: Resultsmentioning

confidence: 99%

“…In distributed network systems, the VBNC bacteria might be a source of recontamination after disinfection is applied for Legionella control, even months after the end of the disinfection process. Additionally, sublethal doses of disinfectant propagate transition to VBNC state (Türetgen, 2008). On the other hand, monochloramine shows construction material-dependent activity but has long residual activity in high temperature and pH levels (Türetgen and Cotuk, 2006;Joseph et al, 2001).…”

Section: Resultsmentioning

confidence: 99%

Survival of Biofilm‐Associated Legionella pneumophila Exposed to Various Stressors

Vatansever¹,

Türetgen²

2015

Water Environment Research

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The performance of a low cost and simple ceramic filter to a membrane bioreactor (MBR) process was evaluated for greywater treatment. The ceramic filter was submerged in an acrylic cylindrical column bioreactor. Synthetic greywater (prepared by shampoo, dish cleaner and laundry detergent) was fed continuously into the reactor. The filter effluent was obtained by gravitational pressure. The average flux performance was observed to be 11.5 LMH with an average hydraulic retention time of 1.7 days. Complete biodegradation of surfactant (methylene blue active substance removal: 99-100%) as well as high organic removal performance (biochemical oxygen demand: 97-100% and total organic carbon: >88%) was obtained. The consistency of flux (11.5 LMH) indicated that the filter can be operated for a long time without fouling. The application of this simple ceramic filter would make MBR technology cost-effective in developing countries for greywater reclamation and reuse. Water Environ. Res., 87, 233 (2015).

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“…The air-dried filter was placed on a microscope slide and observed with a 100 × oil immersion objective (Rodriguez et al, 1992). Images were taken from 10 different areas and the average number of bacteria on the surface was calculated (Turetgen, 2008).…”

Section: Epifluorescence Microscopy Analysismentioning

confidence: 99%

Investigating the effects of different physical and chemical stress factors on microbial biofilm

Vatansever

Türetgen

2018

WSA

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Microorganisms that adhere to surfaces in order to protect themselves from many adverse environmental conditions form a layer called biofilm. Biofilms protect bacteria from changing environmental conditions such as starvation, antibiotics, disinfectants, pH and temperature fluctuation, dryness and UV rays. In this study, biofilms were formed on surfaces of glass coupons in a cooling tower model system over a period of 180 days. The biofilms were treated with various stress factors monthly. These stress factors were: exposure to temperatures of 4°C and 60°C, pH of 3, 5, and 11, 3 M aqueous NaCl and distilled water, as well as, monochloramine at 2, 500, and 1 000 mg/L (ppm). Following the treatment with stress factors, both the numbers of actively respiring bacteria and the total bacteria in the biofilms were determined by CTC-DAPI staining. The aerobic heterotrophic plate counts (HPC) in the biofilms were determined by the conventional culture method of spread plating on R2A agar. The aim of this study was to determine the impact of these stressors on the model cooling tower biofilms. Of the stressors tested, those that had the greatest impact were a temperature of 60°C, pH of 3, 3 M NaCl, and monochloramine at both 500 and 1 000 mg/L. However, when using a non-culture-based viability assay (CTC-DAPI staining), an extremely high number of live bacteria were detected even after applying the most effective stress factors (with the exception of pH 3) of 60°C, 3 M NaCl, monochloramine at 500 and 1 000 mg/L. Results showed that biofilm protects the bacteria from extreme physical and chemical stress conditions. Additionally, the conventional culture technique cannot detect the presence of bacteria that have entered the viable but non-culturable (VBNC) phase; the use of different techniques, such as microscopy and cytometry (flow and solid-phase), is therefore important to obtain more accurate results.

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Induction of Viable but Nonculturable (VBNC) state and the effect of multiple subculturing on the survival ofLegionella pneumophila strains in the presence of monochloramine

Cited by 29 publications

References 19 publications

Effects of ozone on membrane permeability and ultrastructure in Pseudomonas aeruginosa

Effects of ozone on membrane permeability and ultrastructure in Pseudomonas aeruginosa

Survival of Biofilm‐Associated Legionella pneumophila Exposed to Various Stressors

Investigating the effects of different physical and chemical stress factors on microbial biofilm

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