MICROBIAL DRUG RESISTANCE Volume 3, Number 2, 1997 Mary Ann Lieber!, Inc. Prevalence of Serotypes and Antimicrobial Resistance of Streptococcus pneumoniae Strains Isolated from Brazilian Children with Invasive Infections MARIA CRISTINA De CUNTO BRANDILEONE,1 VERA SIMONSEN DIAS VIEIRA,1 SILVANA TADEU CAS AGRANDE,1 ROSEMEIRE COBO ZANELLA,1 MARIA LUIZA LEOPOLDO SILVA GUERRA,1 SERGIO BOKERMANN,1 JOSÉ CÁSSIO De MORAES,2 EVANDRÓ ROBERTO BALDACCI,3 CHEQUER BUFFE CHAMONE,4 MARLUCE APARECIDA ASSUNCÄO OLIVEIRA,4 DEIZE GOMES CAVALCANTI De MATOS,5 TANIA MARIA CATÄO ARRUDA,5 MARINALVA FERREIRA Da COSTA COELHO,6 SUZANA MACHADO D'ÁVILA,7 ANA ROSA Dos SANTOS,7 JOSÉ LUIS Di FABIO,8 and the Pneumococcal Study Group in Brazil for the SIREVA Project* ABSTRACT A laboratory surveillance study was developed in Brazil in 1993 to determine capsular types and antimicro- bial susceptibility of Streptococcus pneumoniae strains. By studying 360 strains isolated from children with invasive infections in three different cities, 8 out of 34 types were identified as being the most prevalent and considered as the reference group for further analyses. This group comprised 77.7% of all strains studied, and includes the types 1, 5, 6A/B, 9V, 14,19F, 19A, and 23F. The prevalence of this reference group was sig- nificantly higher among strains isolated from children with pneumonia than meningitis. Similarly, this group was more prevalent among strains isolated from children 3 to 6 years of age than from children under 2 years of age. Most strains (78.6%) were found to be susceptible to penicillin and only 1.4% showed high resistance to this antibiotic. However, intermediate resistance to penicillin was detected in 20% of the strains. This lab- oratory surveillance will be maintained and extended to other cities of Brazil to better define and monitor the trends of pneumococcal infections for proper control and prevention. INTRODUCTION produced only after the ages of 4 or 6 years.7-18 Thus, infants and young children continue to be at greater risk for pneumo- The considerable morbidity and mortality in infants and coccal infections. The development of a protein-polysaccharide young children worldwide due to Streptococcus pneumo- conjugate vaccine has been globally considered as the new ap- niae infections, together with the more recent recognition of in- proach for prevention of diseases caused by pneumococci in creasing disease caused by pneumococcal strains resistant to young children.19-22-24 Although there are 90 capsular types of one or more antimicrobial agents, have stimulated interest in pneumococci,13 the invasive types are relatively constant in prevention by vaccination.'-2-514-22 However, the available 23- each geographic region, with changes occurring mainly in the valent pneumococcal capsular polysaccharide vaccine does not frequency rank during different periods of time.2^* Because ¡in- stimúlate protective immune response in this population be- munity to pneumococcal diseases is type-specific and few types cause substantial levels of antibodies to polysaccharide can be can be included in the composition of a conjugate vaccine, the 'Bacteriology Division, Adolfo Lutz Institute, 2Center for Epidemiological Surveillance of Säo Paulo State, 'Children Institute, Faculty of Medicine, University of Säo Paulo, Säo Paulo, 'Children Institute, faculty of Medicine, University of Säo Paulo, 4Medical Biology Division, Otavio Magalhäes Institute, Belo Horizonte, 5Dr. Milton Bezerra Sobral Public Health Laboratory, 6Maternal and Infantile Institute, Recife, 7Gen- eral Coordination of Scientific and Technological Development, Department of Health, Brasilia, Brazil and 8Pan American Health Organization, Washington, DC. *Pneumococcal Study Group members are listed at the end of the text. 141