Diagn Microbiol Infect Dis. 2016 Jul 7. pii: S0732-8893(16)30198-5. doi: 10.1016/j.diagmicrobio.2016.07.004. [Epub ahead of print]

Population structure of invasive Streptococcus pneumoniae isolates among Alaskan children in the conjugate vaccine era, 2001 to 2013.

Miernyk KM1, Bulkow LR2, Case SL2, Zulz T2, Bruce MG2, Harker-Jones M2, Hurlburt DA2, Hennessy TW2, Rudolph KM2.

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Abstract

Here we describe the relationships between serotypes, genotypes, and antimicrobial susceptibility among isolates causing invasive pneumococcal disease in Alaskan children during the pneumococcal conjugate vaccine (PCV) era. From 2001 to 2013 we received 271 isolates representing 33 serotypes. The most common serotypes were 19A (29.5%, n= 80), 7F (12.5%, n= 34), 15B/C (6.3%, n= 17), and 22F (4.8%, n= 13). Multilocus sequence typing identified 11 clonal complexes (CC) and 45 singletons. Five CCs accounted for 52% (141/271) of the total: CC199 (21% [n= 57], serotypes 19A, 15B/C), CC191 (12.2% [n= 33], serotype 7F), CC172 (10.3% [n= 28], serotypes 19A, 23A, 23B), CC433 (4.4% [n= 12], serotype 22F), and CC100 (4.4% [n= 12], serotype 33F). The proportion of isolates nonsusceptible to erythromycin and tetracycline increased after 13-valent PCV use (14% [n= 30] versus 29% [n= 14]; P= 0.010) and (4% [n= 9] versus 22% [n= 11]; P< 0.001), respectively. The genetic diversity also increased after 13-valent PCV use (Simpson's diversity index =0.95 versus 0.91; P= 0.022).

Published by Elsevier Inc.

KEYWORDS:

Antimicrobial susceptibility; Molecular epidemiology; Multilocus sequence typing; Pneumococcal conjugate vaccines; Serotypes; Streptococcus pneumoniae

PMID: 27498610 DOI: 10.1016/j.diagmicrobio.2016.07.004

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