Antimicrobial resistance: implications for managing respiratory failure.

The prevalence of antibiotic resistance in respiratory pathogens is increasing rapidly. In the community, resistance to beta-lactam antibiotics has escalated dramatically among Moraxella catarrhalis, Haemophilus influenzae, and Streptococcus pneumoniae. Resistance to penicillin among S. pneumoniae has developed at an alarming rate over the past two decades. Recent studies in the United States have cited rates of penicillin resistance as high as 23.6%, with 9.5% exhibiting high-level resistance. Many of these strains are resistant to multiple antibiotics. Antimicrobial resistance in hospital-acquired pathogens is a problem, which in large part reflects patterns of antibiotic use. Antimicrobial resistance may arise via multiple mechanisms. Pseudomonas aeruginosa and other gram-negative bacilli have become increasingly resistant to beta-lactam antibiotics, including imipenem. Extended-spectrum beta-lactamases are seen with increasing frequency in Enterobacteriaceae, primarily Klebsiella spp. Fluoroquinolone resistance has increased in P. aeruginosa and Staphylococcus aureus and has now been identified in Escherichia coli isolated from hematology wards. Excessive use of antibiotics may promote the emergence and spread of resistant microorganisms. Rigorous infection control measures and modification of antibiotic use patterns may limit or reduce the prevalence of resistant organisms.