title: Comparison of pathogens and their antimicrobial resistance patterns in paediatric, adult and elderly patients in Canadian hospitals.
abstract: OBJECTIVE
  The purpose of this study was to describe the association between age groups and antimicrobial resistance in the most commonly identified pathogens in Canadian hospitals.
  
  
  METHODS
  Between 2007 and 2011, 27,123 clinically significant isolates, comprising 3580 isolates from children ≤ 18 years old, 12,119 isolates from adults 19-64 years old and 11,424 isolates from elderly patients aged ≥ 65 years old, were collected as part of the CANWARD surveillance study from tertiary-care centres across Canada. Antimicrobial susceptibility testing was performed according to CLSI guidelines. A multifactorial logistic regression model was used to determine the impact of demographic factors, including age groups, on antimicrobial resistance.
  
  
  RESULTS
  Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae and Pseudomonas aeruginosa were in the top five organisms for all of the age groups. The proportions of S. aureus that were methicillin resistant, enterococci that were vancomycin resistant and E. coli that produced extended-spectrum β-lactamases were 11.2%, 0.7% and 1.0% for children, 22.8%, 4.6% and 4.3% for adults, and 28.0%, 3.8% and 4.9% for the elderly, respectively. Notable age-related differences in antimicrobial resistance patterns included the following: significantly less methicillin, clindamycin, clarithromycin and trimethoprim/sulfamethoxazole resistance in S. aureus from children; for E. coli, higher cefazolin and ciprofloxacin resistance in the elderly and less ceftriaxone, ciprofloxacin and gentamicin resistance in isolates from children; more S. pneumoniae isolates with penicillin MICs >1 mg/L in children; and for P. aeruginosa, higher resistance rates for meropenem, ciprofloxacin and levofloxacin in adults.
  
  
  CONCLUSIONS
  The assessment of antimicrobial susceptibility patterns by age group revealed that resistance rates are often higher in the older age groups; however, considerable variability in age-specific resistance trends for different pathogen-antimicrobial combinations was noted.
authors.affiliation: Department of Clinical Microbiology, Health Sciences Centre/Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada R3A 1R9. hadam@dsmanitoba.ca
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Adam
authors.forename: Melanie R
authors.initials: MR
authors.lastname: Baxter
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Davidson
authors.forename: Ethan
authors.initials: E
authors.lastname: Rubinstein
authors.forename: Sergio
authors.initials: S
authors.lastname: Fanella
authors.forename: James A
authors.initials: JA
authors.lastname: Karlowsky
authors.forename: Philippe R S
authors.initials: PR
authors.lastname: Lagacé-Wiens
authors.forename: Daryl J
authors.initials: DJ
authors.lastname: Hoban
authors.forename: George G
authors.initials: GG
authors.lastname: Zhanel
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D004352:Drug Resistance, Microbial; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012703:Serotyping; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents