Antimicrobial Coatings to Prevent Biofilm Formation on Medical Devices - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 180

fimbriae in 83920 (Bouckaert et al. 2005 ). Therefore, Trautner et al. ( 2012 ) cova-
lently immobilized mannose on silicone substrates. Pre-exposure of the mannose-
modified surface to Escherichia coli 83920 produced a protective biofilm that
reduced the adherence of Enterococcus faecalis by 80-fold (Trautner et al. 2012 ).
However, in clinical trial, Pseudomonas aeruginosa overgrew Escherichia coli
Hu2117 on urinary catheters (Prasad et al. 2009 ). Therefore, Liao
et al. ( 2012 ) attempted to add a P. aeruginosa lytic phage to the Hu2117 catheter.
Fu et al. ( 2010 ) had previously shown that pretreatment of catheter pieces with a
cocktail of P. aeruginosa lytic phages successfully reduced the 48-h mean Pseu-
domonas aeruginosa biofilm cell density by 99.9 %. Treatment of Escherichia coli
Hu2117-coated catheter segments with P. aeruginosa phages prevented Pseudo-
monas aeruginosa colonization (Liao et al. 2012 ).
4 Contact Lenses
4.1 Contact Lens-Related Bacterial Infection
More than 250 million people in the world wear contact lenses. One of the early
problems for contact lenses was poor oxygenation of the cornea, caused by the fact
that the contacts were made of an impermeable hard acrylic polymer. This problem
was overcome by the advent of the use of a silicone hydrogel polymer for the
manufacture of the lenses. While these lenses are safer for the cornea from an
oxygenation standpoint, they still cause acute red eye infections as well as cases of
corneal ulceration. In fact the advent of silicone hydrogel lenses has not reduced the
incidence of these events (Willcox 2013 ). In a recent report (Yildiz et al. 2012 ), it
was found that out of 507 cases of corneal ulcers, at a single institution,
223 (43.9 %) were contact lens related. In addition, the investigators observed a
significant increase in the number of cases of presumed bacterial keratitis associ-
ated with soft contact lens wear over the 3-year period of their study.
Microbial adhesion to contact lenses is believed to be one of the initiating events
in the formation of many corneal infiltrations, including microbial keratitis, that
occur during contact lens wear (Willcox 2013 ). In earlier days, patients were told to
take their lenses out daily for removal of protein and lipids, which accumulated
from the tear film, as well as for sterilization. Now, newer lenses can be worn for
30 days with FDA approval. This extended wear is potentially a situation where a
biofilm can form and cause grave damage to the eye (Poggio et al. 1989 ; Holden
et al. 1996 ; Sankaridurg et al. 1996b , 1999 , 2000 ; Jalbert et al. 2000 ; Keay
et al. 2000 ; Corrigan et al. 2001 ). In a 1989 epidemiological study (Poggio
et al. 1989 ), the investigators found almost a five times higher incidence of
ulcerative keratitis among extended-wear soft contact lens users compared with
daily wear soft contact lens users. Later studies with extended wear contacts
showed 4-7 times the risk of ulcerative keratitis (Dart et al. 1991 ; Schein