Current and Emergent Control Strategies for Medical Biofilms - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 137

Role of Biosurfactants
Many bacteria are capable of synthesizing and excreting biosurfactants with anti-
adhesive properties (Rodrigues et al. 2004 ; van Hamme et al. 2006 ). Biosurfactants
are amphihilic biological compounds that are produced extracellularly or intracel-
lularly by a wide variety of microorganisms, which include bacteria, yeasts, and
filamentous fungi (Cameotra and Makkar 2004 ). These biosurfactants have prom-
ising applications in biomedical sciences (Singh and Cameotra 2004 ).
Biosurfactants produced by Lactococcus lactis impaired biofilm formation on
silicone rubber (Rodrigues et al. 2004 ). Surfactin from Bacillus subtilis dispersed
biofilms without affecting cell growth and prevented biofilm formation by micro-
organisms such as Salmonella enterica , E. coli , and P. mirabilis (Mireles
et al. 2001 ). Valle et al. ( 2006 ) demonstrated that E. coli expressing group II
capsules released a soluble polysaccharide into their environment that induced
physicochemical surface alterations, which prevented biofilm formation by a
wide range of Gram-positive and Gram-negative bacteria. Many other researchers
have demonstrated the potential for biofilm control by various other biosurfactants
made by bacteria and fungi (Davey et al. 2003 ; Walencka et al. 2008 ). Two
lipopeptide biosurfactants produced by B. subtilis and B. licheniformis have been
shown by Rivardo et al. 2009 to exhibit anti-adhesive activity by selectively
inhibiting biofilm formation of two human pathogenic strains, E. coli CFT073
and S. aureus ATCC29213. Davies and Marques ( 2009 ) found that P. aeruginosa
produces cis-2-decenoic acid, which is capable of inducing the dispersion of
established biofilms and of inhibiting biofilm development by B. subtilis , E. coli ,
S. aureus , Klebsiella pneumoniae , P. aeruginosa , P. mirabilis , S. pyogenes , and the
yeast C. albicans, when applied exogenously. The authors also suggested that this
molecule is functionally and structurally related to a class of short-chain fatty acid
signaling molecules.
Fracchia et al. ( 2010 ) reported biofilm inhibitory activity by a Lactobacillus -
derived biosurfactant against human pathogenic C. albicans . Rufino et al. ( 2011 )
have isolated a biosurfactant rufisan from the yeast Candida lipolytica UCP0988
that exhibited antimicrobial and anti-adhesive activities against many Streptococ-
cus spp. Monteiro et al. ( 2011a , b ) have evaluated the effects of a glycolipid-type
biosurfactant produced by Trichosporon montevideense CLOA72 in the formation
of biofilms in polystyrene plate surfaces by C. albicans CC isolated from the apical
tooth canal. Biofilm formation was reduced up to 87.4 % with use of this
biosurfactant at a 16 mg/mL concentration. This biomolecule did not present any
cytotoxic effects in a HEK 293A cell line at concentrations of 0.25-1 mg/mL. Their
studies indicated a possible application of the referred biosurfactant in inhibiting
the formation of biofilms on plastic surfaces by C. albicans .
Recently, Padmapriya and Suganthi ( 2013 ) found antimicrobial and anti-
adhesive activity of a biosurfactant produced by Candida tropicalis and
C. albicans against a variety of urinary and clinical pathogens such as Bacillus ,
C. albicans , Citrobacter , E. coli , K. pneumoniae , P. mirabilis , P. aeruginosa ,
Salmonella , and S. aureus . A study from our group, Singh et al. ( 2013 ) has