Gram-negative bacterial resistance

Abstract

With the widespread use of antimicrobials, there has been a notable increase of resistant gram-negative organisms worldwide recently. The increase of extended-spectrum β-lactamase (ESBL)-producing E. coli and K. pneumoniae decreased the efficacy of extended-spectrum cephalosporins, and fluoroquinolone and carbapenem resistance in P. aeruginosa further limited the options for the treatment of infections caused by those organisms. Acinetobacter spp. is also an important resistant pathogen in ICU, especially in Asia. The mechanisms of antimicrobial resistance for the gram negatives include multidrug efflux, chromosomal mutations, and transfer of mobile elements such as resistance plasmids or integrons. Although the resistant gram negatives are increasing in a community such as fluoroquinolone resistant E. coli, most infections by antibiotic resistant gram negatives occur in nosocomial setting. The main contributing factors for the antibiotic resistant bacteria in hospitals are heavy use of antibiotics, spread of resistant pathogens, and transfer of mobile elements harboring resistance genes. The emergence and spread of resistant organisms in hospitals caused the increase of morbidity, mortality in patients with infections by those organisms and the increased hospital costs. To get over the recent, fulminant bacterial resistance, more appropriate use of antibiotic, better infection control, and the development of new antibiotics are needed.