Serotypes and clones causing invasive pneumococcal disease before the use of new conjugate vaccines in Catalonia, Spain.

Objectives: The objective of this study was to learn the serotype distribution and clonal composition of pneumococci causing invasive pneumococcal disease (IPD) in children and adults in Spain before the introduction of new 10-valent (PCV10) and 13-valent (PCV13) conjugate vaccines.

Methods: This is a 1-year prospective study including all patients with culture-proved IPD admitted to 30 medical centers in Catalonia, Spain, during the year 2009.

Results: A total of 614 episodes of IPD occurred in 612 patients. The rates of IPD were highest in children aged <24 months and adults >64 years (64.5 and 44.7 per 100,000 population). The burden of disease was mainly due to pneumonia in all age ranges. 609 of 614 strains were serotyped and 47 different serotypes were found. Among the 609 IPD cases with known serotype, 12.2% were caused by PCV7 serotypes, 51% by PCV10 serotypes, and 71.7% by PCV13 serotypes. 608 of 614 isolates were characterized by MLST. The main clonal types detected were ST306, CC191 and CC230.

Conclusions: PCV13 conjugate vaccine offers good coverage against IPD in Catalonia, Spain. However, the high genetic diversity of pneumococci highlights the importance of molecular surveillance systems for monitoring IPD during the vaccination period.

Summary: This study shows that 13-valent conjugate vaccine offers good coverage against invasive pneumococcal disease in children and adults in Spain. However, the high genetic diversity of pneumococci highlights the importance of molecular surveillance systems for monitoring IPD during the vaccination period.