The Evolution of Antimicrobial Resistance in Respiratory Pathogens in Canada: What are the Clinical Consequences?

The use of antimicrobial agents has led to reductions in illnesses and deaths from a variety of infectious diseases. Antimicrobial resistance has followed the introduction of almost every new antimicrobial agent and is now emerging as an important public health problem, especially in respiratory tract pathogens in the community. During the past decade in Canada, a rapid and relentless increase in antimicrobial resistance in Streptococcus pneumoniae and Haemophilus inflluenzae has been witnessed. Adverse implications as a result of the treatment of an infection with an antibiotic to which the offending pathogen is resistant have been recognized in only a few infectious disease syndromes (eg. bacterial meningitis). More often, resistance in vitro does not result in resistance in vivo (eg, respiratory tract infections). Therefore, before recommendations regarding empirical or directed therapy are changed, it is essential that evidence to support those decisions is obtained. More important, the prevention and control of such resistance must be addressed by reducing the burden of antibiotic selective pressure by curtailing inappropriate antibiotic use