Drug resistance in Streptococcus pneumoniae: epidemiology and control

Streptococcus pneumoniae is one of the most important human pathogens, The rapid emergence and global spread of resistance against the most important antibiotics is therefore a serious public health concern. Resistance to bet a-lactam antibiotics is due to alteration of the penicillin-binding protein s (PBPs), enzymes responsible for cell wall synthesis. This alteration impl ies reduced affinity for penicillin and also for other beta-lactam drugs, b ut to a different extent. Under the influence of antibiotic selective press ure, increase in resistance prevalence is due to (1) horizontal transfer of low-affinity PBP gene segments from closely related alpha-haemolytic strep tococci by natural transformation, (2) spread of antibiotic-resistant clone s and (3) further remodelling of PBP genes by mutations and further gene ex change. Although the risk,factors associated with carriage and infection by resistant strains are well known, the effect of community-wide interventio ns is not. Prudent use of antibiotics, vaccination by improved conjugate va ccines and infection control measures are likely to be important in preserv ing the efficacy of available antimicrobial agents.