659. Emergence of PCV13 nonvaccine-specific Streptococcus pneumoniae serotypes 6C and 23A, and serogroups 15, 33, and 35 isolated from children in Kansas City, Missouri
Session: Poster Abstract Session: Pneumococcal Vaccines
Friday, October 21, 2011
Room: Poster Hall B1
Background:  The 13-valent pneumococcal conjugate vaccine (PCV13) was licensed in February 2010 for the prevention of pneumococcal disease in children.  This study examines the incidence of pneumococcal serotypes isolated from children in our institution, with particular focus on PCV13 nonvaccine-specific serotypes strains.

Methods:  Active pneumococcal surveillance was conducted at Children’s Mercy Hospital in Kansas City, MO from 2007 through 2010. All pneumococci isolated from clinical specimens were serotyped by the Quelling capsular swelling reaction.  Patient demographic and clinical data were abstracted from medical chart reviews. Duplicate samples were not included in analysis.

Results:  From 2007 through 2010, 546 pneumococcal clinical isolates were evaluated:  187 (34%) invasive and 359 (64%) non-invasive strains. The most common serotypes identified were 19A (27%), 7 (8%), 3 (6%), which are PCV13 serotypes, and 15 (7%), 23A (6%), 33 (6%), and 35 (6%), which are non-PCV13 serotypes. The annual incidence of these serotypes remained relatively stable except for serotype 35, which increased from an incidence of 2% in 2007 up to 11% in 2010. Overall, 47% of non-invasive isolates and 43% of invasive disease isolates had capsule serotypes not included in PCV13. Penicillin nonsusceptible strains comprised 61% of 19A serotypes, and 23% of serogroup 35 strains. The remaining serotype isolates were nearly 100% penicillin susceptible. Invasive disease occurred more frequently with serogroup 7 and serotype 19A strains. Invasive pneumococcal disease was much less likely to occur in the third quartile compared to other yearly quartiles (p<0.001). 

Conclusion: PCV13 nonvaccine-specific Streptococcus pneumoniae serotypes cause a considerable number of infections in children, and continued surveilllance of pneumococcal serotype distribution is important to guide the development of future pneumococcal vaccines.

Subject Category: I. Adult and Pediatric Vaccines

Douglas Swanson, MD, Children's Mercy Hospital & UMKC School of Medicine, Kansas City, MO and Christopher Harrison, UMKC Sch of Medicine, Kansas City, MO; Children's Mercy Hospital and Clinics, Kansas City, MO


D. Swanson, None

C. Harrison, GlaxoSmithKline: Investigator, Research grant

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