Antibiotic resistance in Streptococcus pneumoniae.

Resistance to penicillin and other antibiotics in Streptococcus pneumoniae has emerged in Australia and around the world in the past decade, and appears to be worsening (e.g., rates of penicillin resistance in Australia rose from 1% in 1989 to 25% in 1997). In Australia, the only oral antibiotic able to treat respiratory infections caused by some multiresistant strains is high-dose amoxycillin. If these strains increase in prevalence, then treatment failures for relatively minor infections (e.g., otitis media) are likely to become common, resulting in repeat antibiotic courses or hospitalisation for parenteral therapy. Therapy for meningitis caused by penicillin-sensitive pneumococcal strains remains high-dose benzylpenicillin, but empirical treatment while awaiting culture and sensitivity results is problematic; neither penicillin nor third-generation cephalosporins cover all strains. Therefore, many authorities recommend vancomycin, usually combined with a third-generation cephalosporin, for treating presumptive or proven pneumococcal meningitis pending penicillin-susceptibility results. As almost all readily available oral antibiotics in Australia select for resistant strains of pneumococci, multiresistant strains will increase in prevalence unless unnecessary antibiotic use and prescription volumes are reduced substantially in the next few years.