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The enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis is enhanced under conditions where reactive oxygen species are neautralised

หน่วยงาน Central Queensland University, Australia

รายละเอียด

ชื่อเรื่อง : The enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis is enhanced under conditions where reactive oxygen species are neautralised
นักวิจัย : Tandon, Puja. , Chhibber, Sanjay. , Reed, Robert (Robert H.)
คำค้น : TBA. , 929999 Health not elsewhere classified. , 060504 Microbial Ecology. , Escherichia coli. , Active oxygen. , Water , Microbial ecology. , Public health. , Chlorine disinfection -- Reactive oxygen species (ROS) -- Selective media -- Sublethal stress
หน่วยงาน : Central Queensland University, Australia
ผู้ร่วมงาน : -
ปีพิมพ์ : 2550
อ้างอิง : http://hdl.cqu.edu.au/10018/42424 , cqu:5455
ที่มา : Tandon, P, Chhibber, S & Reed, R 2007, 'The enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis is enhanced under conditions where reactive oxygen species are neautralised', Letters in Applied Microbiology, vol. 44, pp. 73-78.http://dx.doi.org/10.1111/j.1472-765X.2006.02024.x (viewed 29/3/10)
ความเชี่ยวชาญ : -
ความสัมพันธ์ : Letters in applied microbiology. United Kingdom. : Wiley-Blackwell Publishing Ltd., 2007. Vol. 44, (2007), p. 73-78 6 pages Refereed 0266-8254 , ACQUIRE [electronic resource] : Central Queensland University Institutional Repository.
ขอบเขตของเนื้อหา : -
บทคัดย่อ/คำอธิบาย :

Aim: To investigate the effect of neutralization of reactive oxygen species (ROS-neutralized conditions) on the enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis using selective and nonselective media. Methods: Pure cultures of E. coli NCTC8912 and Ent. faecalis NCTC775 were injured using dilute sodium hypochlorite, at free chlorine levels of 0.6 and 0.9 µg ml-1, respectively, and then enumerated at 37ºC by surface plate counts on nonselective nutrient (N) agar and on several selective media, either under (i) standard aerobic conditions; (ii) aerobic conditions using growth medium, supplemented with 0.05%-w/v sodium pyruvate, to neutralize peroxides; or (iii) conditions designed to neutralize ROS, using a combination of 0.05%-w/v sodium pyruvate in the growth medium, together with incubation in an anaerobic jar. Results: The counts obtained on the nonselective medium were lowest under aerobic conditions in unsupplemented medium, higher in pyruvate-supplemented (peroxide-neutralized) medium and highest for ROS-neutralized conditions. Counts for the selective media were often lower than those for nonselective N (nutrient) agar, with enhancement under peroxide-neutralized conditions and a further increase in counts under ROS-neutralized conditions. Broadly similar observations were made for three other strains of each organism. Conclusions: Chlorine-injured E. coli and Ent. faecalis become sensitive to ROS, giving higher counts under ROS-neutralized enumeration conditions than under conventional aerobic conditions. Significance and Impact of the Study: The enhancement in counts observed under ROS-neutralized conditions indicate that the addition of pyruvate to the growth medium may not fully counteract the effects of sublethal injury under aerobic conditions, which is a novel observation. Thus, ROS-neutralized conditions may be required for optimal enumeration of faecal indicator bacteria. Furthermore, the lower counts, obtained using selective media indicate that the sensitivity of chlorine-injured bacteria to selective agents is not necessarily reversed under ROS-neutralized conditions.

บรรณานุกรม :
Tandon, Puja. , Chhibber, Sanjay. , Reed, Robert (Robert H.) . (2550). The enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis is enhanced under conditions where reactive oxygen species are neautralised.
    กรุงเทพมหานคร : Central Queensland University, Australia.
Tandon, Puja. , Chhibber, Sanjay. , Reed, Robert (Robert H.) . 2550. "The enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis is enhanced under conditions where reactive oxygen species are neautralised".
    กรุงเทพมหานคร : Central Queensland University, Australia.
Tandon, Puja. , Chhibber, Sanjay. , Reed, Robert (Robert H.) . "The enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis is enhanced under conditions where reactive oxygen species are neautralised."
    กรุงเทพมหานคร : Central Queensland University, Australia, 2550. Print.
Tandon, Puja. , Chhibber, Sanjay. , Reed, Robert (Robert H.) . The enumeration of chlorine-injured Escherichia coli and Enterococcus faecalis is enhanced under conditions where reactive oxygen species are neautralised. กรุงเทพมหานคร : Central Queensland University, Australia; 2550.