Diagn Microbiol Infect Dis. 2014 May 24. pii: S0732-8893(14)00214-4. doi: 10.1016/j.diagmicrobio.2014.05.020. [Epub ahead of print]

Serotype distribution and antimicrobial susceptibility of USA Streptococcus pneumoniae isolates collected prior to and post introduction of 13-valent pneumococcal conjugate vaccine.

Mendes RE1, Costello AJ2, Jacobs MR3, Biek D4, Critchley IA4, Jones RN2.

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Abstract

This study evaluated pneumococci cultured from blood or lower respiratory tract specimens from hospitalized patients in the USA (all age groups) during 2011-2012 (N = 1190) and compared findings with those from a similar study performed in 2008 (N = 694). Isolates were tested for susceptibility by broth microdilution and serotypes determined by cpsB sequencing, supplemented with multiplex PCR and capsular swelling assays. Relative percentages of 7-valent pneumococcal conjugate vaccine (PCV7) types were 6.3 and 4.9% in 2008 and 2011-2012, respectively, and the most common PCV7 serotypes (19F and 6B) comprised only 3.7% and 4.0% of all isolates from both periods, respectively. Thirteen-valent pneumococcal conjugate vaccine (PCV13) serotypes represented 42.9% of isolates in 2008 and 30.1% in the second period, and this decrease was driven by 19A and 7F. Non-PCV13 serogroups/serotypes 23A, 15B/15C, 7C, 8, and 31 increased. Penicillin non-susceptibility rates were 9.6-10.0% and 38.9-42.7% when applying the parenteral (i.e. ≥4μg/mL) and oral breakpoints (i.e. ≥0.12μg/mL), respectively. Ceftaroline was the most potent agent tested based on MIC50 and MIC90 values (≤0.015 and 0.12μg/mL, respectively) for both time periods.

Copyright © 2014 Elsevier Inc. All rights reserved.

KEYWORDS:

Pneumococci; Serotype; Vaccine

PMID:

 

24974272

 

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