Antimicrobial Interfaces - Biointerfaces: Where Material Meets Biology - page 400

operations such as hip replacements leading to mortality for as many as one
in six people. 3 In spite of these trends, only one new antibacterial drug,
named linezolid, with a totally novel mechanism of action has been intro-
duced in the past three decades, and the pipeline of new classes of anti-
microbial pharmaceuticals is running dry. 4 Extensive use of antibiotics
offers a potent selective force for antibiotic resistant bacteria and is con-
sequently suggested to be responsible for the rise of resistance. In recent
years, several countries have shown an increased alertness by implementing,
or preparing to implement, regulations that cap the access to antibiotics.
The rapid rise of the New Delhi metallo-b-lactamase-resistance gene among
Enterobacteriaceae in India 5 and its quick spread to the United Kingdom
guided the drug controller general of India to introduce new rules aimed at
stopping the sale of antibiotics without a prescription. 2 Already the human
and economic cost of antibiotic resistance is in a colossal scale. For example,
in the year 2007, the number of infections by multidrug-resistant bacteria
was 400 000, and there were 25 000 deaths associated with it in Europe alone.
The number of extra hospital days associated with this stood at up to
2.5million. 6 The expenditure linked with these infections in terms of extra
hospital costs and eciency losses exceeded 1.5 billion euros each year. 7 In
the United States, antibiotic-resistant infections were blamed for $20 billion
per year in excess health care costs, $35 billion per year in societal costs and
8million additional hospital days per year. 8 Antimicrobial resistance is
quickly becoming a key public health risk and is threatening to invalidate
decades of advances in our ability to treat infections. It is also testing our
perception of how to control communicable diseases. Antimicrobials, es-
pecially antibiotics, are important and valuable agents. Without them rou-
tine medical practices such as hip replacements and cancer chemotherapy
would become much riskier and routine operations could become deadly if
we lose the capacity to tackle infection. The chapter will discuss the bacterial
interfaces with antibacterial materials, which is a key aspect of infection and
potential starting point of drug resistance among bacteria.

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14.2 Bacterial Interfaces
Bacteria can grow in two discrete forms of life and swap between them.
These two forms include (1) a free-living existence, called planktonic growth,
in which they are not adhered to a surface, and (2) a sessile state, called
biofilm growth, which can form communities and is adhered to a surface.
Bacteria growing as a biofilm, such as dental plaque, have been reported as
being up to 1000 times more resistant to antimicrobial treatments compared
to their planktonic counterparts 9 and are responsible for 465% of microbial
infections in humans. 10 Diseases associated with bacterial biofilms include:
lung infections of cystic fibrosis patients, colitis, urethritis, conjunctivitis,
otitis media, infective endocarditis and periodontitis. Moreover, biofilm
associated infections of indwelling medical devices are also of serious con-
cern, because once the device is colonised by infective pathogens it become