PERTACTIN-NEGATIVE BORDETELLA PERTUSSIS STRAINS ARE RARELY DETECTED IN ARGENTINA, A COUNTRY WITH WHOLE-CELL PERTUSSIS PRIMARY VACCINATION

CARRIQUIRIBORDE, FRANCISCO; REGIDOR VICTORIA; HOZBOR, DANIELA; GABRIELLI MAGALÍ

Bruselas

Simposio; Simposio; 12 th Bordetella Symposium; 2019; 2019

International Bordetella Society

Pertussis resurgence had been attributed to waning vaccine immunity and Bordetellapertussis adaptation to escape vaccine-induced immunity. Circulating bacteria differgenotypically from strains used in pertussis-vaccine production. Vaccine antigen-genepolymorphisms occur in countries using either whole-cell (wP) or acellular (aP)vaccines. Pertactin-deficient strains are highly prevalent in aP-vaccinating countries,suggesting strong aP-imposed selection of the circulating bacteria. To corroborate thishypothesis, systematic studies on PRN-prevalence performed in wP-using countriesare needed. We present pertussis-epidemiologic data and molecular characterizationof B. pertussis isolates obtained during 2000-2017 in Buenos Aires, a wP-primaryvaccination-employing area. From 2002 pertussis-case incidences increased withregular 4-year outbreaks, with most cases being in naïve or incompletely vaccinatedunder-one-year-old infants. Of those B. pertussis genotypes 90.6% (317/350) weregenotypically ptxP3-ptxA1-prn2-fim3-2?that genotype occurring in countries usingaP or wP. The low prevalence of pertactin-deficient strains detected in Argentinawould suggest that the loss of pertactin-gene expression might be aP-vaccine-driven.