Epidemiology and Infection



Temporal trends in circulating Bordetella pertussis strains in Australia


M. POYNTEN a1, P. B. McINTYRE a1c1, F. R. MOOI a2, K. J. HEUVELMAN a2 and G. L. GILBERT a3
a1 National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Children's Hospital at Westmead, Sydney, and the University of Sydney, Australia
a2 Research Laboratory for Infectious Diseases, National Institute of Public Health and the Environment (RIVM), The Netherlands
a3 Centre for Infectious Diseases and Microbiology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Sydney, and the University of Sydney, Australia

Article author query
poynten m   [PubMed][Google Scholar] 
mcintyre p.   [PubMed][Google Scholar] 
mooi f   [PubMed][Google Scholar] 
heuvelman k   [PubMed][Google Scholar] 
gilbert g   [PubMed][Google Scholar] 

Abstract

Australia experienced a resurgence of pertussis in the 1990s despite improved vaccine coverage. Although much of the increase was attributable to increased detection of cases in older persons with waning immunity by serology, vaccine changes or alterations in circulating Bordetella pertussis strains may also have contributed. We determined the frequency of variants of B. pertussis pertactin (prn), and pertussis toxin subunit 1 (ptxS1) genes, restriction fragment length polymorphism (RFLP) types and fimbrial serotypes prevalent in Australia prior to, and during the 1990s. Ampoules of the whole-cell vaccine in use prior to 1999 and 84 B. pertussis isolates stored between 1967 and 1998 by laboratories around Australia were analysed. One pertactin allele, Prn3, not detected before 1985, was found in 24 out of 57 (42%) isolates between 1989 and 1998 (P<0·0001). PtxS1A was found in all isolates. IS1002 type 29, found in 17 out of 31 (55%) isolates tested, was the predominant RFLP type. The only difference in fimbrial serotype distribution between the time-periods was an increase in serotype 3 (P=0·054). The whole-cell vaccine contained only the alleles prn1 and ptxS1A. Antigenic shift in B. pertussis may have contributed to the re-emergence of pertussis in Australia. Monitoring these trends will be important as acellular vaccines are introduced and changes are made to pertussis vaccine schedules.

(Accepted October 7 2003)


Correspondence:
c1 Professor P. B. McIntyre, National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, Children's Hospital at Westmead, Locked Bag 4001, Westmead, 2145, NSW, Australia.


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