Bio-enzymes for inhibition and elimination of Escherichia coli O157:H7 biofilm and their synergistic effect with sodium hypochlorite

Abstract

Escherichia coli O157:H7 is one of the most important pathogens worldwide. In this study, three different kinds of enzymes, DNase I, proteinase K and cellulase were evaluated for inhibitory or degrading activity against E. coli O157:H7 biofilm by targeting extracellular DNA, proteins, and cellulose, respectively. The cell number of biofilms formed under proteinase K resulted in a 2.43 log CFU/cm 2 reduction with an additional synergistic 3.72 log CFU/cm 2 reduction after NaClO post-treatment, while no significant reduction occurred with NaClO treatment alone. It suggests that protein degradation could be a good way to control the biofilm effectively. In preformed biofilms, all enzymes showed a significant reduction of 16.4–36.7% in biofilm matrix in 10-fold diluted media ( p < 0.05). The sequential treatment with proteinase K, cellulase, and NaClO showed a significantly higher synergistic inactivation of 2.83 log CFU/cm 2 compared to 1.58 log CFU/cm 2 in the sequence of cellulase, proteinase K, and NaClO ( p < 0.05). It suggests that the sequence of multiple enzymes can make a significant difference in the susceptibility of biofilms to NaClO. This study indicates that the combination of extracellular polymeric substance-degrading enzymes with NaClO could be useful for the efficient control of E. coli O157:H7 biofilms.

Combined DNase and Proteinase Treatment Interferes with Composition and Structural Integrity of Multispecies Oral Biofilms

“…However, DNase I and proteinase K had little effect on the biofilm matrix in the conditions used. In a study by Lim et al [66] Escherichia coli biofilms were treated with DNase I, proteinase K and sodium hypochlorite. When enzymes were added to the preformed biofilms on a stainless steel substrate, none of the DNase I, proteinase K, or NaClO treatment alone significantly reduced the number of viable cells.…”

“…When enzymes were added to the preformed biofilms on a stainless steel substrate, none of the DNase I, proteinase K, or NaClO treatment alone significantly reduced the number of viable cells. However, the combined treatment using proteinase K followed by NaClO, showed a notable reduction of viable cells [66]. The role of eDNA and exoproteins on biofilm formation were investigated by George and Halami [67] by treating mature Lactobacillus plantarum biofilms with DNase I and proteinase K. While untreated biofilms were observed to possess significantly dense population of both live and dead cells, a considerable decrease in the cell density was evident in DNase I-treated and proteinase K-treated biofilms.…”

Antimicrobial Photoinactivation Approach Based on Natural Agents for Control of Bacteria Biofilms in Spacecraft

“…(2) chemical [56][57][58]; (3) physical [59,60]; (4) physicochemical [61][62][63]; (5) physical in combination with natural [64], and (6) natural in combination with chemical [65]. A summary of the bacterial biofilm inhibition/control methods described in the past two years is shown in Figure 1.…”

“…In order not to exclude search results that could be significant for the investigation, a general search term (keyword) "biofilm" was used. According to the scientific articles found in the PubMed database regarding biofilm inhibition and control, all methods, based on their nature, can be divided into six groups: (1) natural (biological) [53][54][55]; (2) chemical [56][57][58]; (3) physical [59,60]; (4) physicochemical [61][62][63]; (5) physical in combination with natural [64], and (6) natural in combination with chemical [65]. A summary of the bacterial biofilm inhibition/control methods described in the past two years is shown in Figure 1.…”

Inhibition of Glucosyltransferase Activity and Glucan Production as an Antibiofilm Mechanism of Lemongrass Essential Oil against Escherichia coli O157:H7

“…Exopolysaccharides are secreted during E. coli O157:H7 biofilm development, and some of them include cellulose, colanic acid, and the adhesin poly-β-1,6-N-acetyl-glucosamine, and these polymers are involved in the maintenance of biofilm structure and cellular protection against disinfectants [4]. It has been reported that cellulose is the major EPS component of E. coli biofilms, and it is essential for its structure and strength, creating cell-cell and cell-surface interactions, retaining water, and avoiding the effect of disinfectants [5]. Previously it was demonstrated that degradation of the EPS matrix of E. coli O157:H7 biofilms (mainly composed by glucans) increased their susceptibility to disinfectants.…”