Biofilm attributes:  Beneficial and detrimental

Humans have made considerable beneficial use of microbial biofilms, primarily in the area of habitat remediation. Water treatment plants, waste water treatment plants and private septic systems remove pathogens and reduce the amount of organic matter in the water or waste water through interaction with biofilms.

This image is a scanning electron micrograph of the  naturally occuring biofilm on sand grains in the clog mat  of a septic system infiltration mound.  The biofilm is composed of mineral particles, a variety of microorganisms,  and a slime or glycocalyx network  (indicated by the arrows), binding the microorganisms and particles together.   Scale Bar= 150 micrometers.

© A.C. Lee Wong, author. ASM MicrobeLibrary
Scanning electron micrograph (SEM) of the naturally occurring biofilm on sand grains in the clog mat of a septic system infiltration mound. 

On the other hand, biofilms can be a serious detriment to the health of patients with any indwelling medical device, such as  catheters or implants.  Catheters introduce an artificial substratum into the body and can cause persistent  infections.  These recurrent infections are due to the  accumulation of mixed biofilms on the artificial surface  of the catheter or other implant.  The glycocalyx of the  bacteria protects them from the effects of antibiotics and  accounts for the persistence of the infection even in the  face of vigorous chemotherapy. In vitro experiments  suggest that bacteria encased in biofilms may be 50 to 500  times more resistant to chemotherapy than planktonic  bacteria of the same strain.  Also, fragments of biofim can slough off at intervals and spread the infection to other  locations within the body.

© M. Yassien, N. Khardori, authors.  ASM MicrobeLibrary
This micrograph shows a large number of Staphylococcus epidermidis cells within a glycocalyx adhering to the catheter surface.

Introduction
How biofilms form
Where biofilms are found
Biofilm attributes
Facts about biofilms
A misconception

---

Return to top
Return to Education homepage

Educational Program Curricula and Teaching Resources
Supported in part by the Waksman Foundation for Microbiology
Developed in collaboration with Dr. John Lennox, Education Editor, Penn State Altoona
©2002-2006 Center for Biofilm Engineering, http://www.erc.montana.edu

NOTE: Links marked by the 3-arrow sign take you off the BiofilmsOnline.com web site. The Center for Biofilm Engineering is not responsible for content of sites marked with the 3-arrow sign.