Characterization of MDR and XDR Streptococcus pneumoniae in Canada, 2007-13

Golden, Alyssa R, Rosenthal, Margot, Fultz, Ben, Nichol, Kimberly A, Adam, Heather J, Gilmour, Matthew W, Baxter, Melanie R, Hoban, Daryl J, Karlowsky, James A and Zhanel, George G (2015) Characterization of MDR and XDR Streptococcus pneumoniae in Canada, 2007-13. Journal of Antimicrobial Chemotherapy, 70 (8). pp. 2199-202. ISSN 0305-7453

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OBJECTIVES: The goal of this study was to characterize Streptococcus pneumoniae demonstrating MDR (resistant to three or more antimicrobial classes) or XDR (resistant to five or more classes) phenotypes, collected from Canada during the CANWARD 2007-13 study. METHODS: From 2007 to 2013 inclusive, S. pneumoniae isolates were collected as a part of the CANWARD surveillance study. MDR and XDR isolates were subjected to PFGE, MLST, molecular detection of pneumococcal pili and macrolide resistance determinants mef(A/E) and erm(B), sequencing of PBPs 1A, 2B and 2X and comparison with Pneumococcal Molecular Epidemiology Network (PMEN) clones. RESULTS: Of 2129 S. pneumoniae isolates collected during the CANWARD 2007-13 study, 61 (2.9%) were found to be MDR. Of these MDR isolates, 43 (70.5%) were XDR. The most common serotypes for both MDR and XDR S. pneumoniae were 19A and 19F. Twenty-nine of 61 isolates (48%) demonstrated resistance to clarithromycin, clindamycin, doxycycline, penicillin and trimethoprim/sulfamethoxazole. All isolates possessed at least one macrolide resistance determinant and mutations in PBPs 1A, 2B and 2X. The most common clone was piliated, XDR ST320, an internationally circulating double-locus variant of Taiwan(19F)-14 (ST236). CONCLUSIONS: Though the rate of MDR S. pneumoniae has remained relatively stable since 2007, XDR strains have emerged in Canada. These strains are virulent, possess resistance determinants and are related to international clones.

Item Type: Article
Additional Information: © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail:
Uncontrolled Keywords: adolescent,adult,pharmacology,epidemiology,drug resistance, multiple, bacterial,epidemiological monitoring,female,genes, bacterial,genotype,humans,male,middle aged,molecular typing,epidemiology,classification,young adult
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: LivePure Connector
Date Deposited: 28 Aug 2020 00:05
Last Modified: 22 Oct 2022 06:42
DOI: 10.1093/jac/dkv107

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