Skip to main content

Comparison of Plate Counts, Petrifilm, Dipslides, and Adenosine Triphosphate Bioluminescence for Monitoring Bacteria in Cooling-Tower Waters

Buy Article:

$22.00 plus tax (Refund Policy)

Effective bacterial control in cooling-tower systems requires accurate and timely methods to count bacteria. Plate-count methods are difficult to implement on-site, because they are time- and labor-intensive and require sterile techniques. Several field-applicable methods (dipslides, Petrifilm, and adenosine triphosphate [ATP] bioluminescence) were compared with the plate count for two sample matrices—phosphate-buffered saline solution containing a pure culture of Pseudomonas fluorescens and cooling-tower water containing an undefined mixed bacterial culture.

For the pure culture, (1) counts determined on nutrient agar and plate-count agar (PCA) media and expressed as colony-forming units (CFU) per milliliter were equivalent to those on R2A medium ( p = 1.0 and p = 1.0, respectively); (2) Petrifilm counts were not significantly different from R2A plate counts ( p = 0.99); (3) the dipslide counts were up to 2 log units higher than R2A plate counts, but this discrepancy was not statistically significant ( p = 0.06); and (4) a discernable correlation ( r 2 = 0.67) existed between ATP readings and plate counts.

For cooling-tower water samples ( n = 62), (1) bacterial counts using R2A medium were higher (but not significant; p = 0.63) than nutrient agar and significantly higher than tryptone-glucose yeast extract (TGE; p = 0.03) and PCA ( p < 0.001); (2) Petrifilm counts were significantly lower than nutrient agar or R2A ( p = 0.02 and p < 0.001, respectively), but not statistically different from TGE, PCA, and dipslides ( p = 0.55, p = 0.69, and p = 0.91, respectively); (3) the dipslide method yielded bacteria counts 1 to 3 log units lower than nutrient agar and R2A ( p < 0.001), but was not significantly different from Petrifilm ( p = 0.91), PCA ( p = 1.00) or TGE ( p = 0.07); (4) the differences between dipslides and the other methods became greater with a 6-day incubation time; and (5) the correlation between ATP readings and plate counts varied from system to system, was poor ( r 2 values ranged from <0.01 to 0.47), and the ATP method was not sufficiently sensitive to measure counts below approximately 10 4 CFU/mL.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Data/Media
No Metrics

Keywords: Petrifilm; Pseudomonas fluorescens; adenosine triphosphate (ATP) bioluminescence; bacteria; bacterial enumeration; cooling towers; dipslides; heterotrophic plate count; plate counts

Document Type: Research Article

Publication date: 2009-04-01

More about this publication?
  • Water Environment Research (WER) is published monthly, including an annual Literature Review. A subscription to WER includes access to the latest content back to 1992, as well as access to fast track articles. An individual subscription is valid for 12 months from month of purchase.

    Water Environment Research (WER) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year.

    Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.
  • Editorial Board
  • Information for Authors
  • Submit a Paper
  • Subscribe to this Title
  • Membership Information
  • Information for Advertisers
  • WEF Bookstore
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more