The incidence of antibiotic resistance in pathogenic bacteria is
rising. Antibiotic resistance can be achieved via three
distinct routes: inactivation of the drug, modification of the
target of action, and reduction in the concentration of drug
that reaches the target. It has long been recognized that
specific antibiotic resistance mechanisms can be acquired
through mutation of the bacterial genome or by gaining
additional genes through horizontal gene transfer. Recent
attention has also brought to light the importance of
different physiological states for the survival of bacteria in
the presence of antibiotics. It is now apparent that bacteria
have complex, intrinsic resistance mechanisms that are often
not detected in the standard antibiotic sensitivity tests
performed in clinical laboratories. The development of
resistance in bacteria found in surface-associated aggregates
or biofilms, owing to these intrinsic mechanisms, is
paramount.