Submitted to: International Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2012
Publication Date: 4/1/2013
Publication URL: https://handle.nal.usda.gov/10113/58143
Citation: Sheffield, C.L., Crippen, T.L., Poole, T.L., Beier, R.C. 2013. Destruction of single-species biofilms of Escherichia coli or Klebsiella pneumoniae subsp. pneumoniae by dextranase, lactoferrin, and lysozyme. International Microbiology. 15:185-189.
Interpretive Summary: Biofilms are ubiquitous in nature, and over 99% of microorganisms on earth live as biofilms. In recent years, bacterial biofilms have been increasingly linked to food safety issues worldwide, and pathogenic bacteria existing in biofilms were identified as the cause of three recent foodborne illness outbreaks. This work was conducted to examine the effectiveness of four commercially available materials (dextranase, lactoferrin, lysozyme, and nisin) to degrade or eliminate biofilms composed of either Klebsiella pneumonia or Escherichia coli. The amount of destruction ranged from 73 to 98% with E. coli and 51 to 100% with K. pneumonia. This research is important because the elimination of unwanted biofilms containing human food pathogens is of importance in commercial animal production and food-processing facilities.
Technical Abstract: The activity of dextranase, lactoferrin, lysozyme, and nisin against biofilms composed of either Klebsiella pneumonia or Escherichia coli was examined using the MBEC Assay™. Mature biofilms were treated and then sonicated to remove the adherent biofilm. This material was quantified using a luminescence dye and correlated with quantity of live bacteria present in the sample. The data was analyzed employing a two-way ANOVA and Bonferroni posttest. Dextranase, lactoferrin, lysozyme, and nisin treatments resulted in percentage reduction of E. coli biofilms ranging from 81 to 84%, 95 to 98%, 73 to 84%, and 77 to 84%, respectively. Lactoferrin (40ug/ml) produced significantly higher percentage reduction (96%) than lysozyme (10ug/ml) which yielded only a 73% reduction in biofilm. No other significant differences occurred. Similar treatments resulted in percentage reduction of K. pneumonia biofilms ranging from 51 to 60%, 100%, 100%, and 97 to 100%, respectively. Dextranase treatments produced significantly lower percentage reductions than all other materials. No other significant differences occurred. No material was capable of complete destruction of both E. coli and K. pneumonia. However, lactoferrin and lysozyme both removed 100% of the K. pneumonia biofilms. It would be reasonable in future testing to employ these materials at higher concentrations against E. coil biofilms.