Antimicrobial susceptibility testing of invasive isolates of Streptococcus pneumoniae from Canadian patients: the SAVE study, 2011-15

Canadian Antimicrobial Resistance Alliance (CARA)

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Abstract

Objectives: To assess antimicrobial susceptibility for 14 agents tested against 6001 invasive isolates of Streptococcus pneumoniae cultured from invasive patient samples from 2011 to 2015 as a part of the annual SAVE study.

Methods: Isolates of S. pneumoniae were tested using the standard CLSI broth microdilution method (M07-A10, 2015) with MICs interpreted by CLSI M100 27th Edition (2017) MIC breakpoints.

Results: From 2011 to 2015, small but significant increases (P ≤ 0.05) in the percentage susceptibility for penicillin (interpreted by all three CLSI MIC breakpoint criteria) (increase of 1.7%-3.2%), clindamycin (3.1%) and ceftriaxone (interpreted by non-meningitis and meningitis CLSI MIC breakpoint criteria) (1.1%-1.5%) were observed. Susceptibility rates for clarithromycin and other commonly tested antimicrobial agents remained unchanged (P > 0.05) over the 5 year period. Isolates with an MDR phenotype (resistance to three or more antimicrobial agent classes) decreased significantly (P < 0.001) from 8.5% in 2011 to 5.6% in 2015. Antimicrobial susceptibility rates were not generally associated (P > 0.05) with patient gender (exception: clarithromycin) but were associated (P ≤ 0.05) with patient age (chloramphenicol and clindamycin) or specimen source (penicillin, doxycycline, trimethoprim/sulfamethoxazole and clindamycin), as well as geographic location in Canada and concurrent resistance to penicillin or clarithromycin.

Conclusions: The in vitro susceptibility of invasive isolates of S. pneumoniae in Canada to penicillin, clindamycin and ceftriaxone increased from 2011 to 2015, coincident with a significant decrease in MDR phenotypes.

Original languageEnglish
Pages (from-to)vii5-vii11
JournalJournal of Antimicrobial Chemotherapy
Volume73
Issue numbersuppl_7
DOIs
Publication statusPublished - 2 Jul 2018

Keywords

  • Adolescent
  • Adult
  • Age Factors
  • Aged
  • Anti-Bacterial Agents/pharmacology
  • Canada
  • Clarithromycin/pharmacology
  • Clindamycin/pharmacology
  • Drug Resistance, Multiple, Bacterial
  • Female
  • Humans
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Penicillins/pharmacology
  • Pneumococcal Infections/blood
  • Respiratory Tract Infections/microbiology
  • Risk Factors
  • Streptococcus pneumoniae/drug effects
  • Young Adult

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