CAPSULAR SEROTYPE AND ANTIBIOTIC-RESISTANCE OF STREPTOCOCCUS-PNEUMONIAE ISOLATES IN 2 CHILEAN CITIES

We compared the incidence of nasopharyngeal colonization by Streptococ cus pneumoniae, the serotypes causing mucosal and invasive diseases, a nd the antibiotic resistance of these strains in patients admitted to three large hospitals and children attending day care centers in two C hilean cities (Santiago and Temuco), The populations in both cities we re similar in ethnic background, socioeconomic status, family size, an d access to medical care. Significant differences in nasopharyngeal co lonization rates, in serotypes causing infections, and in antibiotic r esistance were found between the two cities. In children 0 to 2 years of age, 42% were colonized with S. pneumoniae in Santiago compared to 14% in Temuco. A total of 41 serotypes were identified in both Chilean cities studied. Six serotypes were found only in Santiago; 14 serotyp es were found only in Temuco. Antibiotic-resistant serotypes 6A, 6B, 1 4, 19F, and 23F were detected only in Santiago. We show that important differences in the incidence of nasopharyngeal carriage, infection, a nd S. pneumoniae serotypes can exist in similar populations in differe nt areas of the same country. Our findings are relevant for prevention strategies, antibiotic usage, and vaccine design.