Destruction of single-species biofilms of Escherichia coli or Klebsiella pneumoniae subsp. pneumoniae by dextranase, lactoferrin, and lysozyme.

The aim of this work was to determine the destructive activity of dextranase, lactoferrin, and lysozyme, against single species biofilms composed of either Klebsiella pneumoniae subsp. pneumoniae or Escherichia coli using the MBEC Assay. Luminescence measurements based on quantitation of the ATP present were used to determine the amount of biofilm elimination and correlated with quantity of live bacteria present in the sample. The data were analyzed employing a two-way ANOVA and Bonferroni post-test. Treatments resulted in percentage reductions of E. coli biofilms ranging from 73 to 98%. Lactoferrin (40 microg/ml) produced a significantly higher-percentage reduction than lysozyme (10 microg/ml) (P < 0.05), no other significant differences occurred. Similar treatments resulted in percentage reductions of K. pneumoniae subsp. pneumoniae biofilms ranging from 51 to 100%. Dextranase treatments produced a significantly lower percentage reduction than all other materials (P < 0.05), no other significant differences occurred. No material was capable of complete destruction of both single species biofilms; however, low concentrations of lactoferrin and lysozyme each removed 100% of the K. pneumoniae subsp. pneumoniae biofilm. Low concentrations of lactoferrin or lysozyme might be beneficial to prevent biofilm formation by K. pneumoniae subsp. pneumoniae.