Abstract
Streptococcus pneumoniae is the most common cause of bacterial pneumonia, otitis media, bacteremia, and meningitis in infants, children, and immunocompromised and splenectomized patients. After the introduction of penicillin in 1940, pneumococci were regarded as uniformly sensitive to minimal inhibitory concentrations (less than or equal to 0.05 microgram/mL). This idea persisted until 1967, when the first strain showing increased resistance to penicillin was isolated. Pneumococci with intermediate penicillin resistance recovered from different geographic areas have minimum inhibitory concentrations of 0.1 to 1.0 microgram/mL. In 1977, however, resistant strains were isolated with minimum inhibitory concentrations of 2 to 10 micrograms/mL; subsequently, strains resistant to other antibiotics including tetracycline, sulfonamides, erythromycin, lincomycin, chloramphenicol, clindamycin, streptomycin, and rifampin have also been reported. The authors emphasize the need for continued surveillance of pneumococcal isolates and recommend sensitivity testing of all isolates to penicillin.