Genetic analysis of Bordetella pertussis in Ontario, Canada reveals one predominant clone.
OBJECTIVE
To characterize Bordetella pertussis isolates in Ontario, Canada in order to understand the clonal diversity of strains present in this province.


METHODS
A total of 521 isolates from the period 1998-2006 were analyzed by serotyping, pulsed-field gel electrophoresis (PFGE), and DNA sequencing of their virulence factors of pertactin, fimbriae 3, pertussis toxin subunit 1, and pertussis toxin gene promoter. Characteristics of the Ontario isolates were compared to those described for isolates from Europe and Australia.


RESULTS
A single predominant clone was identified in Ontario, Canada, represented by 83.5% of the 521 isolates analyzed. This clone was characterized by the genotype fim3B, prn2, ptxS1A, and ptxP3 (sequence type (ST)-1), and 72.9% of this clone displayed three closely related PFGE profiles of BpSR11, BpSR5, and BpSR12. Pertussis isolates in Europe with these PFGE profiles and virulence factor genotype are reported as common. The Australian epidemic clone was previously reported to have the genotype prn2 and ptxP3.


CONCLUSIONS
The finding of one predominant B. pertussis clone in Ontario, Canada, with characteristics identical to strains involved in epidemics in Europe and Australia, suggests a potential link of this strain to the resurgence of pertussis in this province.
Vaccine Preventable Bacterial Diseases, National Microbiology Laboratory, 1015 Arlington Street, Winnipeg, Manitoba, Canada R3E 3R2.
Michelle
M
Shuel
Frances B
FB
Jamieson
Patrick
P
Tang
Shirley
S
Brown
David
D
Farrell
Irene
I
Martin
Jan
J
Stoltz
Raymond S W
RS
Tsang
D001426:Bacterial Proteins / Q000235:genetics; D001886:Bordetella pertussis / Q000145:classification / Q000235:genetics*; D016000:Cluster Analysis; D006801:Humans; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D009864:Ontario / Q000453:epidemiology; D012703:Serotyping; D037521:Virulence Factors / Q000235:genetics; D014917:Whooping Cough / Q000453:epidemiology*
D001426:Bacterial Proteins; D037521:Virulence Factors