Center for Biofilm Engineering News Update:  December, 2002 Volume 5, Issue 12   __________________________________________   Research Highlights   Paper Spotlight    Dosing Biocides against Biofilm, by Phil Stewart   One of the longstanding concepts used in the application of antimicrobial agents is the Concentration-Time or CT rule. This rule posits that the efficacy of an antimicrobial treatment will be proportional to the dose concentration and also to the dose duration. For example, the CT rule would predict that a 2h dose at 50 mg/l would have the same effect as a 10h dose of 10 mg/l. While simple and intuitive, our work suggests that the CT rule may mislead, especially when biofilms are involved. The important insight from this work is that the concentration dependence of killing differs profoundly between biofilms and planktonic cells. Dosing protocols developed using planktonic tests cannot be expected to yield optimal dosing strategies when targeting a biofilm. For all four of the antimicrobial agents we investigated – chlorine, glutaraldedhyde, DBNPA, and a quaternary ammonium compound – a stronger dependence on concentration was consistently observed in biofilm experiments. For example, a 200 mg/l dose of glutaraldehyde for 34 min was as effective as a 50 mg/l dose delivered for 650 min. The dose that was four times more concentrated was able to achieve the same effect as the low concentration dose in less than one-tenth the time. We suggest that biofilms are best controlled by using brief, but relatively high concentrations of antimicrobial agents rather than prolonged doses of lower concentration. Grobe, K. J., J. Zahller, and P. S. Stewart. (2002) Role of dose concentration in biocide efficacy against Pseudomonas aeruginosa biofilms. J Ind Microbiol Biotechnol 29:10-15.   _______   Engineered Biofilms to Detect Bioterrorism Agents   The CBE has received federal funding, via the Department of Defense (DOD), for a new initiative in the use of engineered biofilms in the detection of bioterrorism agents. This program is based on the well documented observation that microbial biofilms "trap" organic molecules, viruses, pathogenic bacteria, and fungal and protozoan cysts. Our partner in this cooperative project (MSE Technologies of Butte, MT) has also received extensive support for the development of a "biofilm trap," that will be installed in water distribution systems that are considered to be at risk from bioterrorism. The biofilms in this sidestream trap will capture the molecules, particles, or cells from the bulk fluid and will retain them for detailed analyses. These analyses will include online sensors that will rapidly confirm alarms raised by similar online sensors in the main water lines, but the fact that the biofilm traps will retain agents long after the main bolus has passed any given point will allow us to determine the point at which the agent was introduced, and PCR and other analyses will allow us to attribute the source of the agent in question. The Biofilm Consortium (CBE and MSE) is currently bidding for a large DOD contract to supply needed biofilm expertise to all research groups that are involved in the detection and attribution of any terrorist agents that might be delivered via water distribution systems, because it is widely agreed that biofilms exert a profound effect on the "fate and transport" of these agents.   _______   Biofilms Advance Prostatitis Research   Dr. Richard Veeh will be collaborating with Drs. Rod Donlan and Lisa Hodges of the Center for Disease Control (CDC) on a prostatitis project recently funded by the National Center for Infectious Disease. The CDC is the primary recipient of the $101,000 grant. Collaboratively the researchers will be working on the development of an in vitro model for biofilm growth (pure and defined mixed cultures) on epithelial tissue to use in conjunction with the FISH technique. Ultimately, this technique will be applicable to assessing microbial colonization in clinical prostate tissue biopsies.   _________   Charitable Gift   The Center for Biofilm Engineering would like to thank Church & Dwight Co. for their generous gift of $12,000 to support biofilm research.   _________   MSU's Ultra-Tiny Microscope will Help Treat Ears, Gums   Imagine a microscope so tiny it could fit between your teeth and gums. Or so small, it could pierce your daughter's ear drum and send back pictures of the inflamed cells in her middle ear. Read the full story at http://www.montana.edu/commserv/csnews/nwview.php?article=611     _________________________________________   CBE People in Action     Bill Costerton was invited to present "Montana State University's Center for Biofilm Engineering (CBE), a look at a successful graduated ERC,” to the 2002 Annual Meeting, National Science Foundation (NSF) Engineering Research Centers (ERC), Washington, DC, November 3-4, 2002. Bill Costerton as invited speaker presented “The Role of Biofilms in Infection," Infection Control Spanning the Continuum of Healthcare: Community - Acute - Extended Care. Presented by: Infection Control Professionals of Southern New England, Inc. (ICPSNE), Boston, MA, November 6, 2002. Phil Stewart, presented “Biofilm Control: Present and Future,” at the Life at the Materials Interface Conference, Chestertown, MD, November 4-6, 2002. Zbigniew Lewandowski as invited speaker presented “Use of Microsensors to Study Biofilms” at Procter and Gamble, Cincinnati, OH, November 5-7, 2002. Bill Costerton as invited speaker presented "Biofilms: The Predominant Form of Bacterial Growth in Real Ecosystems," Microbiology Department, Cornell University, Ithaca, NY, November 7, 2002. Anne Camper presented “Regrowth and Retention Time,“ at the International Retension Time Workshop, Seattle, WA, November 8, 2002. Paul Stoodley as invited speaker presented “Dynamic Processes in Bacterial Biofilms: Environmental, Industrial and Medical Implications,” to the Department of Geology seminar series, Portland State University, OR, November 13, 2002. Bill Costerton as invited speaker presented "Biofilms in Nature and Disease," for the IBS515 course at Emory University School of Medicine, Atlanta, GA, November 14-15, 2002. Bill Costerton as the key speaker presented "Biofilms in Nature and Disease," Biofilms for the Auspices of the Academies of Sciences in Belgium Symposium, The Belgian National Committee for Microbiology in collaboration with the Belgian Society for Microbiology, November 22, 2002 . Bill Costerton as invited speaker presented "Biofilms: The Preferred Mode of Growth of Dental Biofilms," Annual Conference of the British Dental Hygienists Association at the Bournemouth International Centre in Bournemouth, U.K., November 23, 2002. Mark Shirtliff presented “Biofilms: Properties, Significance, and Current Research,” to the Department of Environmental Engineering, Washington State University, December 2, 2002. Mark Shirtliff presented “Staphylococcus aureus: Persistence of Infection through Biofilms,” to the Department of Microbiology and Immunology, New York Medical College, NY, December 9, 2002. Thomas Borch presented “Influence of Biogenically Produced Fe(II) and Humic Acid Analogs on the Fate of 2,4,6-trinitrotoluene (TNT),” Fall Meeting, American Geophysical Union, San Francisco, CA, December 6-10, 2002.     __________________________________________   Web Watch     BiofilmsOnline.com   See the BiofilmsOnline.com December issue at http://www.BiofilmsOnline.com.   _______   Recent Web Updates   Check the Recent Web Updates link located on the CBE home page, to view the latest information posted on the CBE web.   See <http://www.erc.montana.edu/Recent%20Web%20Updates/default.htm>      __________________________________________   Newsletter Listserve   The CBE News Update is a listserve newsletter. If you need to subscribe or unsubscribe from the listserve, follow the directions at the following CBE website.   http://www.erc.montana.edu/Res-Lib99-SW/newsarchives/subscribe.htm   An alternative to subscribing to the listserve is to view the CBE News Update on our web page at http://www.erc.montana.edu/Ind-Col99-SW/Current_Newsletter/default.htm. Newsletter archives can be found at http://www.erc.montana.edu/Res-Lib99-SW/newsarchives/index.htm   __________________________________________   Diane Williams  editor of the CBE News Update