Y Kott

Publications of Y Kott

• Bacteriophages of enteric bacteria in drinking water, comparison of their distribution in two countries.

  Authors: R Armon, R Araujo, Y Kott, F Lucena, J Jofre

  Journal of applied microbiology. 12/1997; 83(5):627-33.

  The presence of bacteriophages infecting enteric bacteria was tested in more than 1500 drinking water samples in Israel and Spain. Bacteriophages tested were somatic coliphages, F-specificThe presence of bacteriophages infecting enteric bacteria was tested in more than 1500 drinking water samples in Israel and Spain. Bacteriophages tested were somatic coliphages, F-specific bacteriophages and Bacteroides fragilis bacteriophages. The three groups of bacteriophage were isolated in 100 ml water samples by the presence/absence test with similar frequencies, which ranged from 4.4% for somatic coliphages to 6.1% for bacteriophages infecting Bact. fragilis. In contrast, the frequency of isolation of bacteriophages was significantly higher than the frequency of isolation of faecal coliforms, which averaged only 1.9%. No significant differences were observed between the frequencies of isolation between the samples tested in Spain and those tested in Israel. The percentage of groundwater samples containing faecal coliforms and somatic coliphages was reduced significantly by chlorination, despite known deficiencies. However, there was no effect on the occurrence of F-specific bacteriophages and Bact. fragilis bacteriophages.

• Comparison between the evaluation of bacterial regrowth capability in a turbidimeter and biodegradable dissolved organic carbon bioreactor measurements in water.

  Authors: Y Kott, F Ribas, J Frías, F Lucena

  Journal of applied microbiology. 10/1997; 83(3):347-52.

  In recent years, two different approaches to the study of biodegradable organic matter in distribution systems have been followed. The assimilable organic carbon (AOC) indicates the portion of theIn recent years, two different approaches to the study of biodegradable organic matter in distribution systems have been followed. The assimilable organic carbon (AOC) indicates the portion of the dissolved organic matter used by bacteria and converted to biomass, which is directly measured as total bacteria, active bacteria or colony-forming units and indirectly as ATP or increase in turbidity. In contrast, the biodegradable dissolved organic carbon (BDOC) is the portion of the dissolved organic carbon that can be mineralized by heterotrophic microorganisms, and it is measured as the difference between the inflow and the outflow of a bioreactor. In this study, at different steps in a water treatment plant, the bacterial regrowth capability was determined by the AOC method that measures the maximum growth rate by using a computerized Monitek turbidimeter. The BDOC was determined using a plug flow bioreactor. Measurements of colony-forming units and total organic carbon (TOC) evolution in a turbidimeter and of colony-forming units at the inflow/outflow of the bioreactor were also performed, calculating at all sampling points the coefficient yield (Y = cfu/delta TOC) in both systems. The correlations between the results from the bioreactor and turbidimeter have been calculated; a high correlation level was observed between BDOC values and all the other parameters, except for Y calculated from bacterial suspension measured in the turbidimeter.

• A simple, rapid and sensitive presence/absence detection test for bacteriophage in drinking water.

  Authors: R Armon, Y Kott

  The Journal of applied bacteriology. 05/1993; 74(4):490-6.

  A rapid, simple and sensitive direct bacteriophage presence detection method for 500 ml drinking water samples has been developed. The method includes a glass device consisting of a jar containingA rapid, simple and sensitive direct bacteriophage presence detection method for 500 ml drinking water samples has been developed. The method includes a glass device consisting of a jar containing the water sample and an immersible probe filled with solidified soft agar containing bacterial host cells. Host bacteria in logarithmic phase were added to the experimental volume and the probe was submerged. The entire device was incubated in a water bath at 36 degrees C. Plaques of somatic bacteriophage infecting Escherichia coli strain CN13, could be detected within 3 h. Male-specific bacteriophages infecting E. coli F+ amp were detected within 6 h. Bacteriophage infecting the anaerobe Bacteroides fragilis subsp. fragilis HSP40 were detected after 8 h. Application of this device and the associated technique, enabled a one-step detection of 1 pfu of E. coli or Bact. fragilis specific bacteriophage in 500 ml drinking water samples.

• Pig erythrocyte ghost cells used for concentration of enteric viruses from experimentally contaminated clinical specimens.

  Authors: R Armon, I Neeman, Y Kott

  Journal of medical virology. 01/1990; 29(4):256-60.

  A simple, rapid and efficient procedure of virus concentration from urine, cerebrospinal fluid (CSF), and feces was developed. Pig erythrocyte ghost cells were used to adsorb and elute such virusesA simple, rapid and efficient procedure of virus concentration from urine, cerebrospinal fluid (CSF), and feces was developed. Pig erythrocyte ghost cells were used to adsorb and elute such viruses as poliovirus LSC-1, echovirus 6, and human rotavirus (clinical isolate). In urine and CSF, the adsorption efficiency range was 80-100% and elution was from 85% to greater than 100%. In addition, poliovirus LSC-1 was used as an experimental model to examine this procedure under various clinical conditions, such as calcium, glucose, amino acids, and urea at high concentrations. These were added to normal urine specimens to simulate pathological conditions. The results suggest that pig erythrocyte ghost cells are an efficient matrix for adsorption and elution of enteric viruses found in clinical specimens of urine, CSF, and feces. This method might be useful in virus concentration from clinical specimens and for preparative microscopy and other clinical laboratory methods that require subsequent virus concentration.

• Ghost cells as sorption matrix for virus concentration from water.

  Authors: R Armon, Y Kott, I Neeman

  Applied and environmental microbiology. 07/1984; 47(6):1337-40.

  Pig erythrocyte membranes were used as adsorbent material for the concentration of bacteriophage phi x-174, MS-2, and f2 from 5 ml of saline solution. The adsorption was carried out at pH 3.5, andPig erythrocyte membranes were used as adsorbent material for the concentration of bacteriophage phi x-174, MS-2, and f2 from 5 ml of saline solution. The adsorption was carried out at pH 3.5, and the elution was carried out at pH 7.0. Compared with adsorption on 3% beef extract, bacteriophage adsorption on erythrocyte ghost cells yielded 93 to 100%, and elution was 92 to 100%, whereas beef extract organic flocculation yielded adsorption of 0 to 98.8% and elution of 61 to 86.6%. The same procedure but with poliovirus LSC-1 gave 100% adsorption and 91 to 129% elution.