Population-based surveillance for invasive pneumococcal disease and pneumonia in infants and young children in Goiânia, Brazil.

BACKGROUND: Streptococcus pneumoniae is the leading cause of vaccine-preventable death in children <5 years of age globally. We determined incidence rates of invasive pneumococcal disease (IPD), clinical and chest X-ray-confirmed pneumonia (CXR+Pn), S. pneumoniae serotype distribution, and antimicrobial susceptibility in children in Goiânia, Brazil. METHODS: Prospective, population-based surveillance was conducted from May 2007 to May 2009 in children 28 days to <36 months of age presenting to all 33 pediatric healthcare services (outpatient departments, emergency rooms, hospitals) in Goiânia. Eligibility criteria were temperature ≥39.0 °C in the previous 24h and/or clinical suspicion of pneumonia or IPD. RESULTS: 14,509 subjects were enrolled. Median age was 14.0 months. S. pneumoniae was detected in 64 samples from 62 subjects: 58 (90.6%) blood; 4 (6.3%) cerebrospinal fluid; and 2 (3.1%) pleural fluid. Incidence rate of IPD (culture- and polymerase chain reaction-positive) for all children aged 28 days to <36 months was 57.5/100,000; overall incidence for culture-positive only was 54.9/100,000. Age stratification of culture-positive-only subjects found the highest rates were, 114.6/100,000 and 69.8/100,000, respectively, for the 6 months to <12 months and 12 months to <24 months age groups. The overall incidence of invasive pneumonia and pneumococcal meningitis was 37.2/100,000 and 5.3/100,000, respectively. The most common IPD serotypes were 14 (45.0%), 6B (13.3%), 18C (6.7%), and 23F (5.0%). Eight isolates (13.3%) were penicillin nonsusceptible. The cumulative percentages of serotypes included in 7-valent, 10-valent, and 13-valent pneumococcal conjugate vaccines were 78.3%, 80.0%, and 88.3%, respectively. The overall incidence of clinical pneumonia and CXR+Pn was, 9598/100,000 and 3428/100,000, respectively. CXR+Pn rates for hospitalized and non-hospitalized subjects were 1751/100,000 and 1677/100,000, respectively. CONCLUSIONS: The burden of IPD and pneumonia is considerable in children in a large Brazilian city, and is seen in hospitalized as well as ambulatory subjects. Vaccination with pneumococcal conjugate vaccines has the potential to decrease this burden.

Non-typeable Streptococcus pneumoniae carriage isolates genetically similar to invasive and carriage isolates expressing capsular type 14 in Brazilian infants.

OBJECTIVES: We have recently found a high prevalence of non-typeable pneumococcal isolates (NTPn) circulating in day-care centers in Central Brazil, besides serotype 14 isolates. We therefore examined the genetic relationship among NTPn and serotype 14 from carriage and invasive pneumococcal isolates obtained from children attending emergency rooms enrolled in a population-based surveillance. METHODS: The isolates were characterized by Quellung reaction serotyping, PCR for the presence of pneumolysin and the loci for a capsule gene (cpsA) and the type 14 gene (cps14H) in all NTPn, and by multilocus sequence typing and pulsed field gel electrophoresis. RESULTS: 87.2% of the isolates were clustered into nine clusters. The major cluster included 41 pneumococcal serotype 14 (28 carriage and 13 invasive isolates) and two NTPn related to the global pneumococcal clone Spain(9V)-3. Overall, 95.4% of the NTPn carriage strains were genetically related to carriage or invasive strains expressing serotype 14. A dominant NTPn lineage was found, that grouped 14 pneumococcal strains. Almost half of the multidrug-resistant isolates grouped into the NTPn cluster. CONCLUSION: These findings provide baseline data to assess the impact of the pneumococcal vaccination on the molecular epidemiology of Streptococcus pneumoniae. Changes in frequency of NTPn isolates and also genetic changes should be carefully monitored post vaccination, to detect potential vaccine-escape or replacement disease by capsule switched strains, especially in areas where colonization with NTPn has been frequently observed.