Genetic and antigenic analysis of invasive serogroup C Neisseria meningitidis in Canada: A decrease in the electrophoretic type (ET)-15 clonal type and an increase in the proportion of isolates belonging to the ET-37 (but not ET-15) clonal type during the period from 2002 to 2009 |
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| Authors: | Jianwei Zhou Frances Jamieson Sharon Dolman Linda MN Hoang Prasad Rawte Raymond SW Tsang |
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| Affiliation: | 1.Public Health Agency of Canada, Winnipeg, Manitoba;;2.Ontario Agency for Health Protection and Promotion;;3.Faculty of Medicine, University of Toronto;4.Public Health Protection and Prevention Branch, Ontario Ministry of Health and Long-Term Care, Toronto, Ontario;;5.Public Health Microbiology and Reference Laboratory, British Columbia Centre for Disease Control, Vancouver, British Columbia |
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| Abstract: | BACKGROUND:Serogroup C meningococcal disease has been endemic in Canada since the early 1990s, with periods of hyperendemic disease documented in the past two decades. The present study characterized invasive serogroup C meningococci in Canada during the period from 2002 to 2009.METHODS:Serogroup C meningococci were serotyped using monoclonal antibodies. Their clonal types were identified by either multilocus enzyme electrophoresis or multilocus sequence typing.RESULTS:The number of invasive serogroup C Neisseria meningitidis isolates received at the National Microbiology Laboratory (Winnipeg, Manitoba) for characterization has dropped from a high of 173 isolates in 2001 to just 17 in 2009, possibly related to the introduction of the serogroup C meningococcal conjugate vaccine. Before 2006, 80% to 95% of all invasive serogroup C meningococci belonged to the electrophoreic type (ET)-15 clonal type, and the ET-37 (but not ET-15) type only accounted for up to 5% of all isolates. However, beginning in 2006, the percentage of the ET-15 clonal type decreased while the ET-37 (but not ET-15) type increased from 27% in 2006 to 52% in 2009. The percentage of invasive serogroup C isolates not belonging to either ET-15 or ET-37 also increased. Most ET-15 isolates expressed the antigenic formula of C:2a:P1.7,1 or C:2a:P1.5. In contrast, the ET-37 (but not ET-15) isolates mostly expressed the antigens of C:2a:P1.5,2 or C:2a:P1.2.CONCLUSION:A shift in the antigenic and clonal type of invasive serogroup C meningococi was noted. This finding suggests vigilance in the surveillance of meningoccocal disease is warranted. |
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| Keywords: | ET-15 ET-37 Meningococci Serogroup C |
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