Problems with antimicrobial resistance in gram-positive cocci.

The development of antimicrobial resistance has almost invariably accompanied the therapeutic use of antimicrobial agents. Newer antimicrobials have succeeded partly but not entirely in overcoming the problem of resistance. Antimicrobial resistance in gram-positive cocci has achieved its greatest prominence in the past 15 years. There has been a steady erosion of antimicrobial activity against gram-positive cocci. The presentations in this symposium dealt with some of the important problems of antimicrobial resistance in gram-positive cocci, including methicillin resistance and multidrug resistance in staphylococci, penicillin resistance in pneumococci, and vancomycin resistance in enterococci. A related problem that warrants attention is the potential for explosive development of macrolide resistance in gram-positive cocci. This potential is particularly pertinent because the popularity of a number of new macrolides has led to a striking increase in their use. This occurrence will almost certainly be accompanied by a generalized increase in resistance in gram-positive cocci.