title: Invasive Streptococcus pneumoniae in Canada, 2011-2014: Characterization of new candidate 15-valent pneumococcal conjugate vaccine serotypes 22F and 33F.
abstract: Emerging non-PCV-13 Streptococcus pneumoniae serotypes 22F and 33F are included in a new 15-valent pneumococcal conjugate vaccine currently undergoing clinical trials in the United States. This study assessed the antimicrobial resistance and genetic relatedness of these two emerging pneumococcal serotypes. Of the 5075 invasive pneumococcal isolates collected in Canada from 2011 to 2014, 9.8% (497/5075) were serotype 22F and 3.2% (160/5075) were serotype 33F. Despite being among the top 4 most common serotypes collected each study year, serotype 22F demonstrated ≥98% susceptibility to all antimicrobials tested except clarithromycin and few were multi-drug resistant (MDR) (0.8%, 4/497). Serotype 22F isolates were highly clonal (ST433), with two isolates showing high relatedness to MDR international clone Sweden(15A)-25 (ST63). Conversely, serotype 33F showed greater antimicrobial resistance, greater genetic diversity and a higher proportion of MDR isolates (8.8%, 14/160). The prevalence of serotype 33F increased significantly during 2011-2014 (p=0.005).
authors.affiliation: Department of Medical Microbiology, College of Medicine, Faculty of Health Sciences, University of Manitoba, 727 McDermot Avenue, Winnipeg, Manitoba R3E 3P5, Canada. Electronic address: umgoldea@myumanitoba.ca.
authors.forename: Alyssa R
authors.initials: AR
authors.lastname: Golden
authors.affiliation: Department of Medical Microbiology, College of Medicine, Faculty of Health Sciences, University of Manitoba, 727 McDermot Avenue, Winnipeg, Manitoba R3E 3P5, Canada; Clinical Microbiology-Health Sciences Centre, Diagnostic Services Manitoba, MS673-820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9, Canada.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Adam
authors.affiliation: Department of Medical Microbiology, College of Medicine, Faculty of Health Sciences, University of Manitoba, 727 McDermot Avenue, Winnipeg, Manitoba R3E 3P5, Canada.
authors.forename: George G
authors.initials: GG
authors.lastname: Zhanel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015373:Bacterial Typing Techniques; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000627:therapeutic use; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects / Q000302:isolation & purification; D018074:Vaccines, Conjugate / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: 15-Valent pneumococcal conjugate vaccine; Canada; Invasive pneumococcal disease; Serotype 22F; Serotype 33F