[Impact of bacterial resistance on severe infections].

Since many years, the antimicrobial resistance increases as well as for community-acquired as for nosocomial infections. Antibiotic-resistant pneumococci are neither more nor less virulent susceptible strains. Except for immunocompromised patients, the outcome of penicillin-resistant pneumococcal infections have been similar to those in patients who are infected by susceptible ones. Current levels of S. pneumoniae resistance to penicillin and cephalosporin are not associated to an increase in mortality in children with meningitis if adequate doses of antibiotics are given. Because empiric therapy has changed, antibiotic resistance has not been associated with increased mortality. This statement can be extended to Meningococcus, for which 32 to 50% of the strains have a decreased susceptibility to penicillin. For nosocomial infections, S. aureus is the main studied pathogen. Several studies report that in patients with severe diseases (bacteremia or pneumonia) methicillin resistance of S. aureus had no significant impact on patient outcome after adjustment for different confounders. The main risk factor for mortality is the severe underlying diseases rather than the resistance as well for methicillin--resistant S. aureus, as for vancomycin resistant enterococci, Klebsiella with extended spectrum beta lactamase and Enterobacters. Recommendations for controlling epidemiologic surveillance, using barrier precautions and limiting the use of antibiotics as well in the hospital as in the community must be undertaken.