163
E. coli, Pseudomonas fluorescens, Aggregatibacter actinomycetemcomitans,
S. aureus, Bordetella bronchiseptica, B. parapertussis and B. pertussis (Kalpan
2009). Deoxyribonuclease I (DNase I) degrades extracellular DNA (eDNA), which
is a major structural and functional component of the biofilm matrix that act as
matrix adhesin in most bacterial species. Deoxyribonuclease treatment is able to
dissolve 12–60 h old P. aeruginosa biofilms. However, streptococcal deoxyribonuclease streptodornase is more potent biofilm disruptor. Deoxyribonuclease I is also
reported to detach biofilms of S. epidermidis, Enterococcus faecalis, S. pneumoniae,
Campylobacter jejuni, Acinetobacter baumannii, Haemophilus influenzae,
Klebsiella pneumoniae, Escherichia coli, and Streptococcus pyogenes (Kalpan
2009). Polysaccharide degrading anti biofilm enzymes (amylase, alginate lyase, cellulase and lysozyme) and certain quorum quenching enzymes (N-acyl homoserine
lactonases and acylases) help in biofilm disruption. Thermostable quorum quenching lactonase from Geobacillus kaustophilus (GKL) belongs to the phosphotriesterase like lactonase (PLL) family of the amidohydrolase superfamily which is able to
disrupt biofilm formation by A. baumannii most effectively (Chow et al. 2014).
Several proteolytic enzymes like Savinase, Pandion, Resinase, Spezyme and
Paradigm, Pronase are reported to be effective against P. fluorescens,
Pseudoalteromonas sp., P. aeruginosa biofilms (Meireles et al. 2016).
7.5.4 Acidic Electrolyzed Water
More recently, acidic electrolyzed water (AEW) has been shown to be effective for
eradicating biofilms associated with food borne pathogen which was experimentally
confirmed employing green fluorescent protein tagged E. coli. Reduction in fluorescent signal from biofilm associated cells due to treatment confirmed the superior
efficiency of acidic electrolyzed water. The underlying mechanism was confirmed
to trigger extracellular polymeric substance disruption as revealed from deformation of the carbohydrate C-O-C bond and deformation of the aromatic rings in the
amino acids tyrosine and phenylalanine. Further, scanning electron microscopy
(SEM) images confirmed the altered biofilm architecture characterized by broken
and detached non uniform bacterial biofilms. Acidic electrolyzed water also eradicates biofilms formed by both Gram negative bacteria (Vibrio parahaemolyticus)
and Gram positive bacteria (Listeria monocytogenes) combined with effective inactivation of the detached cells (Fig. 7.3). However, the effectiveness is thought to be
dependent upon the particular bacterial species (Han et al. 2017). Pathogenicity of
S. aureus associated biofilm on the solid phase surface, particularly for indwelling
medical devices and equipments in food processing industries. Electrolyzed water
can effectively kill S. aureus, thereby removing the bacterial biofilm, which is otherwise difficult to remove for strong adherence to solid phase surface. Basic electrolyzed water (BEW) having more biofilm removal efficiency indicate that pH of
electrolyzed water plays a significant role in biofilm control. Further, acidic
7 Control of Bacterial Biofilms for Mitigating Antimicrobial Resistance
E. coli, Pseudomonas fluorescens, Aggregatibacter actinomycetemcomitans,
S. aureus, Bordetella bronchiseptica, B. parapertussis and B. pertussis (Kalpan
2009). Deoxyribonuclease I (DNase I) degrades extracellular DNA (eDNA), which
is a major structural and functional component of the biofilm matrix that act as
matrix adhesin in most bacterial species. Deoxyribonuclease treatment is able to
dissolve 12–60 h old P. aeruginosa biofilms. However, streptococcal deoxyribonuclease streptodornase is more potent biofilm disruptor. Deoxyribonuclease I is also
reported to detach biofilms of S. epidermidis, Enterococcus faecalis, S. pneumoniae,
Campylobacter jejuni, Acinetobacter baumannii, Haemophilus influenzae,
Klebsiella pneumoniae, Escherichia coli, and Streptococcus pyogenes (Kalpan
2009). Polysaccharide degrading anti biofilm enzymes (amylase, alginate lyase, cellulase and lysozyme) and certain quorum quenching enzymes (N-acyl homoserine
lactonases and acylases) help in biofilm disruption. Thermostable quorum quenching lactonase from Geobacillus kaustophilus (GKL) belongs to the phosphotriesterase like lactonase (PLL) family of the amidohydrolase superfamily which is able to
disrupt biofilm formation by A. baumannii most effectively (Chow et al. 2014).
Several proteolytic enzymes like Savinase, Pandion, Resinase, Spezyme and
Paradigm, Pronase are reported to be effective against P. fluorescens,
Pseudoalteromonas sp., P. aeruginosa biofilms (Meireles et al. 2016).
7.5.4 Acidic Electrolyzed Water
More recently, acidic electrolyzed water (AEW) has been shown to be effective for
eradicating biofilms associated with food borne pathogen which was experimentally
confirmed employing green fluorescent protein tagged E. coli. Reduction in fluorescent signal from biofilm associated cells due to treatment confirmed the superior
efficiency of acidic electrolyzed water. The underlying mechanism was confirmed
to trigger extracellular polymeric substance disruption as revealed from deformation of the carbohydrate C-O-C bond and deformation of the aromatic rings in the
amino acids tyrosine and phenylalanine. Further, scanning electron microscopy
(SEM) images confirmed the altered biofilm architecture characterized by broken
and detached non uniform bacterial biofilms. Acidic electrolyzed water also eradicates biofilms formed by both Gram negative bacteria (Vibrio parahaemolyticus)
and Gram positive bacteria (Listeria monocytogenes) combined with effective inactivation of the detached cells (Fig. 7.3). However, the effectiveness is thought to be
dependent upon the particular bacterial species (Han et al. 2017). Pathogenicity of
S. aureus associated biofilm on the solid phase surface, particularly for indwelling
medical devices and equipments in food processing industries. Electrolyzed water
can effectively kill S. aureus, thereby removing the bacterial biofilm, which is otherwise difficult to remove for strong adherence to solid phase surface. Basic electrolyzed water (BEW) having more biofilm removal efficiency indicate that pH of
electrolyzed water plays a significant role in biofilm control. Further, acidic
7 Control of Bacterial Biofilms for Mitigating Antimicrobial Resistance