Genotypic and phenotypic characterization of Bordetella pertussis strains used in different vaccine formulations in Latin America.

AIM

To characterize Bordetella pertussis vaccine strains in comparison with current circulating bacteria.

METHODS AND RESULTS

Genomic and proteomic analyses of Bp137 were performed in comparison with other vaccine strains used in Latin America (Bp509 and Bp10536) and with the clinical Argentinean isolate Bp106. Tohama I strain was used as reference strain. Pulse-field gel electrophoresis (PFGE) and pertussis toxin promoter (ptxP) sequence analysis revealed that Bp137 groups with Bp509 in PFGE group III and contains ptxP2 sequence. Tohama I (group II) and Bp10536 (group I) contain ptxP1 sequence, while Bp106 belongs to a different PFGE cluster and contains ptxP3. Surface protein profiles diverged in at least 24 peptide subunits among the studied strains. From these 24 differential proteins, Bp10536 shared the expression of ten proteins with Tohama I and Bp509, but only three with Bp137. In contrast, seven proteins were detected exclusively in Bp137 and Bp106.

CONCLUSIONS

Bp137 showed more features in common with the clinical isolate Bp106 than the other vaccine strains here included.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results presented show that the old strains included in vaccines are not all equal among them. These findings together with the data of circulating bacteria should be taken into account to select the best vaccine to be included in a national immunization programme.