18.01.3.2 Glycopeptides

An important approach to preventing microbes developing resistance to antibiotics, is to limit the use of antibiotics, so that the microbes do not have the opportunity to develop resistance. Thus, when new antibiotics are developed there is initially an attempt to limit their use, so that they remain useful in serious infections. This occurred with the glycopeptide, vancomycin. Like the β-lactams, glycopeptides inhibit the synthesis of the bacterial cell wall. The glycopeptides do this by inhibiting the enzymes involved in building the peptidoglycan structure (transglycosidases). International guidelines have been developed to restrict the use of vancomycin to try to prevent the development of vancomycin resistant bacteria. Vancomycin is reserved mainly for treatment of life-threatening infections with Methicillin-Resistant Staphylococcus Aureus (MRSA). As the name implies MRSA is resistant to the penicillins, including methicillin. Staphylococci are the commonest cause of hospital bloodstream infections. MRSA spreads quickly among elderly and seriously ill patients. Unfortunately, the effectiveness of vancomycin against MRSA is declining.