Surveillance of invasive Streptococcus pneumoniae infection in Quebec, Canada, from 1984 to 1986: serotype distribution, antimicrobial susceptibility, and clinical characteristics.

Four hundred and sixty-eight strains of Streptococcus pneumoniae isolated from blood or normally sterile body fluids in 14 Quebec, Canada, hospitals between 1 July 1984 and 31 December 1986 were serotyped, their susceptibilities to antimicrobial agents were determined, and the laboratory data were correlated with the clinical information. The distribution pattern of the serogroups and serotypes was similar to that observed previously in Quebec and to that in other parts of Canada and in the United States. No regional variation was observed. The distribution of serogroups and serotypes was different in pediatric patients (less than 18 years old) when compared with that of adults (P less than 0.001). Overall, 94% of the strains were represented in 23-valent vaccine. The total mortality rate was 12.8% and increased with age: 1.6% in pediatric patients, 14.8% in patients 18 to 64 years old, and 31% in those greater than or equal to 65 years old (P less than 0.001). In patients 18 to 64 years old, the mortality rate was higher when an underlying condition that could have justified prior vaccination was present (P = 0.008). In patients greater than or equal to 65 years old, the mortality rates were similar in those with and those without underlying conditions, suggesting that vaccine use in all patients greater than or equal to 65 years old might be appropriate. Only six patients had received pneumococcal vaccine before infection. Only 15 strains (3.2%) were moderately susceptible or resistant to one or more of the antimicrobial agents tested. Six strains were moderately susceptible to penicillin G, and none was fully resistant.