Emergence of penicillin-resistant invasive pneumococci in a single American community.

Three decades ago, penicillin-resistant strains of Streptococcus pneumoniae were first reported. Since then, myriad penicillin resistant strains of S. pneumoniae have been identified worldwide and in the United States. No resistant or intermediate resistant strains have been reported in West Virginia because testing has not been done. Between 1983 and 1994, the authors' surveillance of invasive pneumococcal disease in metropolitan Huntington, West Virginia, identified 356 pneumococcal strains from blood and other usually sterile sites, including 110 strains belonging to serotypes 6, 9, 14, 19, and 23, the main serotypes exhibiting penicillin resistance. The authors tested these serotypes for penicillin susceptibility by the E-test. Sixteen (14.5%) strains of types 6, 9, 14, 19, and 23 exhibited intermediate resistance to penicillin. No highly resistant strains were identified. Most of the intermediate resistant strains of types 9, 14, and 23 were detected in epidemiologic years 1992-1994. The increasing number of intermediate resistant penicillin strains signals the need for routine testing of invasive pneumococcal strains for penicillin susceptibility and necessitates appropriate antibiotic usage.