Carriage of penicillin resistant pneumococci.

A survey of 303 urban and 156 rural children showed nasopharyngeal carriage of relatively resistant Streptococcus pneumoniae organisms in 14.2% and 19.2% of children, respectively. These organisms have minimum inhibitory concentrations for penicillin in the range of 0.12-1 microgram/ml. An analysis of 40 relatively resistant S. pneumoniae strains showed resistance to co-trimoxazole in 47.5%, trimethoprim in 42.5%, fusidic acid in 20%, tetracycline in 2.5%, and rifampicin in 5%. All the strains were susceptible to chloramphenicol and vancomycin, while the minimum inhibitory concentrations of third generation cephalosporins and imipenem were comparable with or lower than those of penicillin. Eighty three per cent of the strains tested belonged to serogroups 6 and 19. These findings are discussed in relation to the poor clinical response to treatment with penicillin for relatively resistant S. pneumoniae meningitis, and the minimum inhibitory concentrations of alternate agents under review for treatment of systemic pneumococcal disease are presented.