Center for Biofilm Engineering

News Update: 

November, 2006

Volume 9, Issue 11

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Research Highlights

Paper Spotlight

by Andreas Nocker

Novel chemical for live-dead distinction improves estimate of pathogenic risk

The detection of bacterial pathogens presents a great challenge and affects many important fields. Testing for pathogens and quantifying them has relied on cultivation techniques using a variety of specific growth conditions for different pathogens. In the recent years, terms like viable-but non-culturable (VBNC) have raised concerns about whether cultivation-based approaches are reliable in microbial risk assessment. Moreover, the long time required for cultivation does not leave time for preventive measures in the case of positive testing. These shortcomings might be partly overcome by molecular techniques that have evolved rapidly in the last decade. The potentially useful techniques include quantitative PCR or DNA-chips for detection and enumeration of specific pathogens or indicator organisms. However, the application of DNA-based diagnostics is hampered by its inability to discriminate between live and dead cells. Due to the persistence of DNA in the environment after cells have lost their viability, DNA-based assays can lead to an overestimation of pathogenic risk or to false-positive results, since signals can originate from both live and dead cells. In this publication, we present a novel chemical − propidium monoazide (PMA) − which has potential to overcome this problem. Treatment of microbial mixtures comprising both live and dead cells (based on membrane integrity), results in selective signal suppression from dead cells with compromised cell membranes. We provide evidence that PMA can be applied to a wide range of species across the bacterial kingdom, presenting a major advantage over the previously described ethidium monoazide (EMA). This fast and easy-to-perform treatment might thus improve molecular diagnostics by limiting the results to a more relevant fraction of the bacterial community.

"Comparison of Propidium Monoazide with Ethidium Monoazide for Differentiation of Live vs. Dead Bacteria by Selective Removal of DNA From Dead Cells"
Nocker, A., C.-Y. Cheung, and A.K. Camper
J. Microbiol. Meth., 67(2):310-320 (2006)
Read the paper's abstract at: http://www.biofilm.montana.edu/Res-Lib99-SW/pubs/Abstracts/2006/06-016.htm

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New Industrial Associates

We welcome two new Industrial Associate member companies - Molnlycke Health Care and Medi-Flex.

Molnlycke Health Care makes surgical and wound care products. Maria Werthen will be the designated representative. Their website is: http://www.molnlycke.com/item.asp?id=14951&lang=2&si=179&si=179.

Medi-Flex of Leawood, Kansas manufactures pre-operative skin wipes and antiseptics. The designated representative will be Cindy Crosby, VP for Clinical Affairs. Their website is: http://www.medi-flex.com/chloraprep_com/about_medi-flex.html.

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Media Coverage

CBE Director Dr. Phil Stewart was interviewed and some of the CBE's images were used in a recent issue of the weekly ACS publication Chemical and Engineering News. Stereo microscope images from the CBE Annual Report project showed up in the C&EN cover story "Bacterial Conversations: Using a chemical language, bacteria coordinate everything from infection to plaque buildup". Read the article at: http://pubs.acs.org/cen/coverstory/84/8443cover.html

Also read a C&EN companion article "Battling Biofilms," at: http://pubs.acs.org/cen/coverstory/84/8443cover2.html

This issue of C&EN also featured a cover image from the CBE's BIOGLYPHS project.
Cover Image: http://pubs.acs.org/subscribe/journals/cen/84/i43/toc/toc_i43.html

The image was selected from the CBE’s Bioglyphs project. Read more about it at: http://www.biofilm.montana.edu/Bioglyphs/default.htm

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New Employee

Kelly Kirker, Research Scientist, was recently hired on a one-year post-doc appointment in the Medical Biofilms Laboratory to work on the Wound Care project. Kelly has a PhD in Bioengineering (University of Utah, SLC) and a BS in Materials Science and Engineering (University of Michigan). She will be working on host immune response which will include cell culture and Flow Cytometric (FACS) analysis of host immune cells.

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CBE People in Action

Phil Stewart as an invited speaker will present “Mechanisms of Antibiotic Tolerance in Staphylococcal Biofilms,” at the Biofilm-Material Interactions Symposium H which is held within the Fall 2006 Materials Research Society meeting in Boston, MA, November 29–30, 2006. See program information at: http://www.mrs.org/s_mrs/doc.asp?CID=6982&DID=178449

Anne Camper as invited speaker presented “Biofilms in Industrial Water Systems,” HPC NA Fall Hygiene Unilever Symposium, Trumbull, CT, November 14–16, 2006.

Andreas Nocker presented “Molecular Monitoring of Disinfection Efficacy,” Water Quality Technology Conference, Denver, CO, November 5–11, 2006.

M.S. Rahman presented “Investigation of Nitrification and Corrosion in Domestic Plumbing System,” Water Quality Technology Conference, Denver, CO, November 5–11, 2006.

Zbigniew Lewandowski as invited speaker presented “Recent Advances in Marine Antifouling,” International Biodegradation and Biodegradation Conference, Chennai, India,
October 29–November 12, 2006.

Phil Stewart as an invited speaker presented "Alternative Strategies for Controlling Biofilms,” at the 2006 American Association of Pharmaceutical Scientists (AAPS) Annual Meeting and Exposition, San Antonio, Texas, October 29–November 2, 2006. See program information at: http://www.aapspharmaceutica.com/meetings/annualmeet/am06/index.asp

Zbigniew Lewandowski presented a poster entitled “Factors Affecting Toxic Shock Syndrome Toxin (TSST-1) Expression in Staphylococcus aureus Biofilms,” 2006 Annual Meeting Infectious Diseases Society of America, Toronto, Canada, October 13–16, 2006.

Phil Stewart and Paul Sturman gave an “Introduction to Biofilms,” workshop to Bausch & Lomb, Rochester, New York, October 3, 2006. Topics addressed included Understanding Biofilm Control; Laboratory Biofilm Growth Systems and Analyses; Techniques of Biofilm Analysis ; and CBE Interaction with Industry.

 

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Web Watch

BiofilmsOnline.com

See the BiofilmsOnline.com November issue at http://www.BiofilmsOnline.com.

Subscribe to the monthly newsletter by registering at: http://www.biofilmsonline.com/cgi-bin/biofilmsonline/newsletter_signup.html

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The CBE News Update is a listserve newsletter. If you wish to subscribe or unsubscribe from the listserve, follow the directions at the following CBE website.

http://www.biofilm.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.biofilm.montana.edu/Ind-Col99-SW/Current_Newsletter/default.htm. Newsletter archives can be found at http://www.biofilm.montana.edu/Res-Lib99-SW/newsarchives/index.htm.

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