A Surveillance of invasive Streptococcus pneumoniae in Argentina 1994-2007: Changes in serotype distribution , serotype coverage of pneumococcal conjugate vaccine and antibiotic resistance

Abstract

Streptococcus pneumoniae is a prevalent cause of invasive diseases in children, justifying continuous surveillance programs such as by the SIREVA group (Pan American Health Organization). The aim of this study was to determine the serotype distribution of S. pneumoniae causing invasive disease in children < 6 years old, the serotype coverage of the pneumococcal conjugate vaccine 7-valent (PCV7), 10-valent (PCV10) and 13-valent (PCV13), and antibiotic resistance, from 1994 to 2007. During this period, 2205 invasive S. pneumoniae were included in the study. Although 49 different capsular types were identified, 12 serotypes accounted for 86% of all isolates. These were prevalent hroughout the study period with serotype 14 predominating. Penicillin non-susceptible S. pneumoniae was detected in 33.2% of all isolates. The coverage of PCV7, PCV10 and PCV13 from 2004 to 2007 for children < 2 years old was 51.7%, 72.4% and 84.5%, respectively. The data demonstrates a decline in serotype 14, and an increase in serotypes 1 and 19A in the study period. Resistance to penicillin and trimethoprim-sulfamethoxazole decreased, while resistance to erythromycin increased. These results demonstrate the need for the introduction of a conjugate pneumococcal vaccine and continuing surveillance to monitor changes in serotypes distribution and antimicrobial resistance.