Characterization of invasive isolates of S. pneumoniae, H. influenzae, and N. meningitidis in Latin America and the Caribbean: SIREVA II, 2000-2005

ABSTRACT

OBJECTIVES: To analyze the phenotypical characteristics and the susceptibility to antibiotics of the circulating strains of Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis circulating in Latin America and the Caribbean from 2000-2005. Potential coverage by conjugate vaccines was evaluated. METHODS: Conventional methods were used to study the distribution of the serotypes or serogroups of 17 303 strains of S. pneumoniae, 2 782 strains of H. influenzae, and 6 955 strains of N. meningitidis isolated from cases of pneumonia, meningitis, sepsis, bacteriemias, and other invasive processes. The antimicrobial susceptibilities of the study strains were evaluated. The isolates came from 453 sentinel surveillance sites in 19 countries in Latin America and four in the Caribbean, as part of the SIREVA II (Network Surveillance System for the Bacterial Agents Responsible for Pneumonia and Meningitis) project. RESULTS: S. pneumoniae serotype 14 was the most frequently isolated (21.1 percent), especially in children under 6 years of age (29.1 percent). The potential coverages by hepta-, nona-, deca-, and trideca-valent antipneumonia conjugate vaccines were 59.0 percent, 73.4 percent, 76.5 percent, and 85.9 percent, respectively. Of the isolates, 63.3 percent were sensitive to penicillin. H. influenzae serotype b was present in 72.2 percent of the isolations from children under 2 years of age, whereas 8.6 percent produced serotypes a, c, d, e, and f, and 19.2 percent could not be serotyped. The rate of H. influenzae beta-lactamase-producing strains isolated from children under 2 years of age was 16.3 percent. The most frequent N. meningitidis serogroups were B (69.0 percent) and C (25.7 percent); 65.8 percent and 99.2 percent of the strains were susceptible to penicillin and rifampicin, respectively. CONCLUSIONS: These results highlight the importance of comprehensive epidemiological surveillance of S. pneumoniae, H. influenzae and N. meningitidis in Latin America and the Caribbean. The great heterogeneity found in the distribution of S. pneumoniae serotypes among the countries studied could reduce immunization coverage. Conducting a specific analysis of each country to adjust the introduction of new conjugate vaccines and determine the best immunization plan is recommended