Introduction: the challenge of multiresistance.

Antibiotic resistance is selected by antibiotic usage, which, in hospitals at least, is likely to increase driven by changes in demography, international development and advances elsewhere in medicine. Maintaining mankind's ability to treat infection therefore depends on better utilisation of present antimicrobials--better regimens as well as less unnecessary use--and on better infection control, but also on the development of new vaccines and antibiotics. Current developments include a raft of new agents active against meticillin-resistant Staphylococcus aureus (MRSA), but few that offer any advance against Gram-negative organisms. One that does have increased anti-Gram-negative activity, compared with earlier analogues, is tigecycline, a glycylcycline derivative of minocycline.