title: Dominance of two genotypes of Bordetella pertussis during a period of increased pertussis activity in Alberta, Canada: January to August 2012.
abstract: OBJECTIVE
  The purpose of this study was to undertake an epidemiological analysis of an increase in Bordetella pertussis activity during the period January 1 to August 31, 2012 in Alberta, Canada. B. pertussis testing was done using an IS481 real-time PCR assay with PCR-positive and indeterminate specimens cultured and stored for further analysis.
  
  
  METHODS
  Laboratory data were linked to Alberta Health (AH) cases that were reported in the Communicable Disease Reporting System (CDRS) to identify case isolates; exclusion criteria were used to avoid biases. Case isolates were analyzed at the National Microbiology Laboratory (NML) by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Pertussis immunization data were extracted from the Alberta Provincial Immunization Repository (Imm/ARI) and linked to the pertussis cases.
  
  
  RESULTS
  Using PFGE and MLST, 52 case isolates could be divided into two main sequence type groups: 41 cases belonged to the ST-1 group (ST-1 and the novel ST-19) and 11 cases belonged to the ST-2 group (ST-2 and the novel ST-20). Of the total cases genotyped (N=52), 18 (34.6%) had a history of immunization, 28 (53.8%) were not immunized, and six (11.6%) had an unknown immunization history. Of the total non-immunized cases, 25/28 (89.2%) belonged to the ST-1 group. Furthermore, of the 41 ST-1 group cases, 25 were not immunized compared to only three of the ST-2 group cases (p=0.0004, Fisher's exact test).
  
  
  CONCLUSIONS
  This study shows the dominance of two genotypes of B. pertussis in our jurisdiction and indicates less pertussis immunization in individuals infected with the ST-1 group.
authors.affiliation: Alberta Health, Surveillance and Assessment Branch, Edmonton, Alberta, Canada; University of Calgary, Calgary, Alberta, Canada.
authors.forename: Kimberley
authors.initials: K
authors.lastname: Simmonds
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Walter MacKenzie Health Science Centre, University of Alberta Hospital, 8440 112 Street, Edmonton, Alberta T6G 2J2, Canada.
authors.forename: Sumana
authors.initials: S
authors.lastname: Fathima
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Walter MacKenzie Health Science Centre, University of Alberta Hospital, 8440 112 Street, Edmonton, Alberta T6G 2J2, Canada; University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Chui
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Walter MacKenzie Health Science Centre, University of Alberta Hospital, 8440 112 Street, Edmonton, Alberta T6G 2J2, Canada.
authors.forename: Marguerite
authors.initials: M
authors.lastname: Lovgren
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Walter MacKenzie Health Science Centre, University of Alberta Hospital, 8440 112 Street, Edmonton, Alberta T6G 2J2, Canada.
authors.forename: Penny
authors.initials: P
authors.lastname: Shook
authors.affiliation: National Microbiology Laboratory, Health Canada, Winnipeg, Manitoba, Canada.
authors.forename: Michelle
authors.initials: M
authors.lastname: Shuel
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Walter MacKenzie Health Science Centre, University of Alberta Hospital, 8440 112 Street, Edmonton, Alberta T6G 2J2, Canada; University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tyrrell
authors.affiliation: National Microbiology Laboratory, Health Canada, Winnipeg, Manitoba, Canada.
authors.forename: Raymond
authors.initials: R
authors.lastname: Tsang
authors.affiliation: Provincial Laboratory for Public Health (ProvLab), Walter MacKenzie Health Science Centre, University of Alberta Hospital, 8440 112 Street, Edmonton, Alberta T6G 2J2, Canada. Electronic address: steven.drews@albertahealthservices.ca.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Drews
mesh_terms: D000416:Alberta / Q000453:epidemiology; D001886:Bordetella pertussis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D058885:Multilocus Sequence Typing; D010567:Pertussis Vaccine; D060888:Real-Time Polymerase Chain Reaction; D014611:Vaccination; D014917:Whooping Cough / Q000453:epidemiology / Q000382:microbiology* / Q000517:prevention & control
chemical_list: D010567:Pertussis Vaccine
keywords: Genotype; Immunization; Pertussis; Public health