Nasopharyngeal colonization by Streptococcus pneumoniae in children and adults before the introduction of the 10-valent conjugate vaccine, Paraguay

Streptococcus pneumoniae is a cause of invasive diseases such as pneumonia, meningitis, and other serious infections among children and adults in Paraguay. This study was conducted to establish S. pneumoniae baseline prevalence, serotype distribution, and antibiotic resistance patterns in healthy children aged 2 to 59 months and adults ≥60 years of age prior to the introduction of PCV10 in the national childhood immunization program in Paraguay. Between April and July 2012, a total of 1444 nasopharyngeal swabs were collected, 718 from children aged 2 to 59 months and 726 from adults ≥60 years of age. The pneumococcal isolation, serotyping, and antibiotic susceptibility testing were performed using standard tests. Pneumococcal colonization prevalence was 34.1% (245/718) in children and 3.3% (24/726) in adults. The most frequent pneumococcal vaccine-types (VT) detected in the children were 6B (42/245), 19F (32/245), 14 (17/245), and 23F (20/245). Carriage prevalence with PCV10 serotypes was 50.6% (124/245) and PCV13 was 59.5% (146/245). Among colonized adults, prevalence of PCV10 and PCV13 serotypes were 29.1% (7/24) and 41.6% (10/24), respectively. Colonized children were more likely to share a bedroom, have a history of respiratory infection or pneumococcal infection compared to non-colonized children. no associations were found in adults. However, no significant associations were found in children and neither in adults. Vaccine-type pneumococcal colonization was highly prevalent in children and rare in adults in Paraguay prior to vaccine introduction, supporting the introduction of PCV10 in the country in 2012. These data will be useful to evaluate the impact of PCV introduction in the country.