Freezing Inactivation of <i>Escherichia Coli</i> and <i>Enterococcus Faecalis</i> in Water: Response of Different Strains

Gao, Wa; Leung, Ka Yin; Hawdon, N.

doi:10.2175/106143009x407348

Cited by 28 publications

(21 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It should again be noted that the initial sludge bacteria numbers were lower than expected possibly due to long transportation times. The findings of this research are in agreement with previously reported decreases in sludge microbial densities after freezethaw treatment (Sanin et al 1994;Chu et al 1999;Gao et al 2009). Sludge characteristics, freezing and storage temperatures, and number of freeze-thaw cycles are expected to affect the inactivation rates of microorganisms during freeze-thaw treatment.…”

Section: Resultssupporting

confidence: 93%

“…Freezing temperature, storage time, and freeze-thaw cycles affected the survival of Escherichia coli and Enterococcus faecalis, and greater inactivation efficiencies were achieved under longer storage time and higher freezing temperatures (Gao et al 2006(Gao et al , 2009. It was suggested that longer freezing times result in cell dehydration (Mazur 1965).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Diak

Örmeci

Proux³

2011

Water Science and Technology

View full text Add to dashboard Cite

Freeze-thaw conditioning of RBC (Rotating Biological Contactor) sludge was tested using a pilot-scale freezing bed placed in a mobile freezer operated at -10°C. Sludge samples from a remote mining exploration facility were flown in every 2 weeks, and added to the freezing bed in 8 layers of 10 cm thick. Approximately 4 months after the first layer of sludge was added, the pilot unit was removed from the freezer and thawed at ambient temperatures. After one day of thawing, the solids concentration increased from 2.6% to 16.2%. The final cake solids concentration was 21%. Melt water had increasing turbidity, COD, TSS, VSS, nitrogen and phosphorus concentrations during the thawing period. Freeze-thaw conditioning also decreased the initial densities of fecal coliforms and Salmonella in sludge. The results of this study showed that freeze-thaw technology successfully dewatered RBC sludge without the need for mechanical equipment, and is a sustainable option for sludge dewatering in cold and remote regions.

show abstract

Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Diak

Örmeci

Proux³

2011

Water Science and Technology

View full text Add to dashboard Cite

show abstract

“…They also observed increased inactivation of all the isolates proportional to the number of F/T cycles with higher resistance of E. faecalis . They did not observe higher resistance of E. coli , but the freezing duration is not indicated in the material and method section and they used water as liquid of conservation (15).…”

Section: Discussionmentioning

confidence: 99%

Aerobic bacteria as Escherichia coli can survive in ESwab^TM medium after a 3 month-freezing at −80°C but not after multiple thawing

Saliba

Carbonnelle

Lescat

2019

Preprint

View full text Add to dashboard Cite

14Pretesting of procedures for specimen conservation should be part of preliminary 15 studies for trials especially when quantification of bacteria must be performed in a second 16 time. Quantitative epidemiological studies of multidrug resistant organisms sampled from 17 rectal swabs could be then particularly favored. The aim of this preliminary study, was to 18 evaluate the performance of the flocked swab with liquefied Amies transport medium 19 ESwab TM , for the survival evaluation of aerobic bacteria, from rectal swab sampling 20 42 (5). Likewise, those species are also opportunistic pathogens and quantitative studies of the 43 prevalence, bacterial load and diversity of these species as well as E. coli in their natural 44 3 environment, which is the digestive gut, are essential (3, 6, 7). 45 Several steps in the analyses of bacteria from digestive gut are crucials and are directly 46 related to a good diagnostic performance in the Clinical Microbiology laboratory. For 47

show abstract

“…Both of the E. faecalis strains are considered to be opportunistic pathogenic. The procedures used by [23] were followed for cell solution preparation. The ATCC strain 51299 was vancomycin resistant.…”

Section: A Test Microbes and Cell Solution Preparationmentioning

confidence: 99%

Response of Different Strains of Enterococcus faecalis to UV Inactivation after Freezing

Gao¹,

Williams²

2013

IJESD

Self Cite

View full text Add to dashboard Cite

Abstract-Response of two strains of Enterococcus faecalis bacteria, ATCC strain 29212 and ATCC strain 51299 (vancomycin resistant) to UV inactivation after survived freezing treatment was examined. The test microorganisms were frozen at -7 °C, -15 °C or -30 °C with one, three or five freeze and thaw cycles prior to UV irradiation to investigate the effect of freezing temperature and freeze thaw cycles on the efficacy of UV inactivation. Experimental results suggest that freezing influenced the response of Enterococcus faecalis cells to UV irradiation. Freezing treated cells behaved differently compared to those had not frozen.Index Terms-Enterococcus faecalis, freezing treatment, UV disinfection, waterborne pathogens, water and wastewater treatment. I. INTRODUCTIONConventional municipal wastewater treatment systems can significantly reduce the population of microorganisms; however, after treatment wastewater treatment plant (WWTP) effluents may still contain high numbers of fecal bacteria. Published research data indicated that the portion of pathogenic and antibiotic resistant bacteria in WWTP effluent remained at significant concentrations or even increase [1]- [5]. Release of pathogenic and antibiotic resistant microorganisms with WWTP effluents is a growing public health concern [6], [7]. Multiple antibiotic resistant fecal coliforms and enterococci including vancomycin resistant Enterococcus (VRE) have been detected in influent, effluent, and sludge from municipal wastewater treatment plants [8][9]. WWTPs provide a favorable environment for gene transfer due to high bacterial densities and nutritional richness of the influents [4], [8], [9]. Applications of UV disinfection in water and wastewater treatment systems have increased in recent years in Canada. Numerous research has been carried out to find the correlations between water quality, bacterial sensitivity and UV disinfection efficiency [10]-[12], the impact of cold temperatures on UV disinfection processes, especially, the responses of the pathogenic microorganisms after experiencing freezing to UV is however seldom examined [13], [14]. As a treatment alternative, natural or mechanical freezing has been used for various water or wastewater treatment, sludge pre-treatment or conditioning, and desalination [15]-[19]. Depending on the requirements of the finished water quality, UV disinfection may be needed after freezing treatment. Waterborne microorganisms might behave differently to UV Manuscript received December 5, 2012; revised February 27, 2013. W. Gao is with Department of Civil Engineering, Lakehead University, Thunder Bay, ON, Canada (e-mail: wagao@lakeheadu.ca).irradiation after survived freezing compared to those without experience freezing [13], [14], [20]. A recent study by Williams at al. [14] revealed that after freezing waterborne microorganisms such as Escherichia coli, Enterococcus and Bacillus behaved differently to UV irradiation compared to those had not frozen. Freezing affected the response of these microbes, a lower UV inactivat...

show abstract

Freezing Inactivation of Escherichia Coli and Enterococcus Faecalis in Water: Response of Different Strains

Cited by 28 publications

References 28 publications

Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Aerobic bacteria as Escherichia coli can survive in ESwab^TM medium after a 3 month-freezing at −80°C but not after multiple thawing

Response of Different Strains of Enterococcus faecalis to UV Inactivation after Freezing

Contact Info

Product

Resources

About

Freezing Inactivation of Escherichia Coli and Enterococcus Faecalis in Water: Response of Different Strains

Cited by 28 publications

References 28 publications

Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Aerobic bacteria as Escherichia coli can survive in ESwabTM medium after a 3 month-freezing at −80°C but not after multiple thawing

Response of Different Strains of Enterococcus faecalis to UV Inactivation after Freezing

Contact Info

Product

Resources

About

Aerobic bacteria as Escherichia coli can survive in ESwab^TM medium after a 3 month-freezing at −80°C but not after multiple thawing