Serotype distribution and antimicrobial resistance patterns of invasive isolates of Streptococcus pneumoniae: Alaska, 1991-1998

From January 1991 through December 1998, a total of 1046 pneumococcal isola tes were received from 23 laboratories participating in the statewide surve illance system. Of these, 1037 were recovered from normally sterile sites ( blood and cerebrospinal and pleural fluid) and were available for serotypin g and susceptibility testing. Ninety-two percent of these isolates were ser otypes represented in the 23-valent pneumococcal polysaccharide vaccine. Se rotypes in the 7-valent pneumococcal conjugate vaccine (4, 6B, 9V, 14, 18C, 19F, and 23F) were recovered from 72% of Alaska Natives and 84% of non-Nat ive children <5 years old with invasive disease. Statewide, 7.3% and 3.2% o f isolates had intermediate and high levels of resistance to penicillin, re spectively; 9.2% were resistant to erythromycin (minimal inhibitory concent ration, greater than or equal to 1 mu g/mL) and 19% to trimethoprim/sulfame thoxazole (minimal inhibitory concentration, greater than or equal to 4/76 mu g/mL). Twelve percent of invasive isolates were resistant to greater tha n or equal to 2 classes of antibiotics, of these, serotype 6B accounted for 33%, and 63% were recovered from children <5 years old.