Aims: Pertussis is an important vaccine preventable disease. It is still a major cause of infant morbidity and mortality in the world. Although the incidence of pertussis was successfully reduced after vaccination, the resurgence of pertussis has been reported in many countries even with high vaccination coverage. Genetic variation in virulence factors is one of the important causes for pertussis reemergence. We investigated genetic characteristics and allele types of 3 important virulence associated genes, including ptxC, tcfA, and fhaB in clinical B. pertussis isolates collected from different provinces of Iran and vaccine strains.
Materials & Methods: Genomic DNA was extracted and ptxC, tcfA, and fhaB gene regions were amplified, using specific PCR primer. DNA sequencing was performed and data were analyzed.
Findings: ptxC2, tcfA2, and fhaB1 were the dominant alleles with 87.5%, 97.5%, and 97.5% frequencies, respectively. Vaccine strains B. pertussis 134 and B. pertussis 509 contain the genotypes ptxC2- tcfA2-fhaB1 and ptxC2- tcfA2-fhaB1.
Conclusion: Results for dominant alleles in ptxC2, tcfA2, and fhaB1 genes in Iran are consistent with dominant alleles of other countries such as Netherland, Finland, and Italy. It seems that ptxC2, tcfA2, and fhaB1 are the dominant circulating alleles in many countries after vaccination period, while vaccine strains have different alleles occasionally. More reported cases in recent years despite high coverage vaccination in Iran and genetic distances between clinical and vaccine strains suggest that antigenic changes in virulence factors possibly have an important role in the survival and evolution of the bacteria.

Aims: Bordetella pertussis is a gram negative and obligated aerobic bacterium that causes pertussis disease and it is a specific pathogen in human. Pertussis is an acute respiratory infection and leads to death in infants. The aim of this study was to analyze housekeeping genes in Bordetella pertussis vaccine strains by multilocus sequence typing (MLST).
Materials and Methods: In the present experimental study, 4 samples of 134 and 509 bacterial strains and 2 standard samples of Tohama I, and 18323 were collected. After biochemical tests, the samples were cultured and separated and the genomic purification of DNA was done by Phenol–chloroform technique and analyzed by MLST. After genome sequencing, the analysis was performed by standard software such as Clustalw 2, MEGA 5.04, and DNASIS Max 3. Sequence similarity of 16S rDNA gene nucleotides was performed, using BLAST software with sequences recorded in the GenBank genome database to compare and determine the sequences similarity.
Findings: Regarding the created bands and the sequence of the game, the housekeeping genes in Bordetella pertussis vaccine strains were approved. The results of the PCR reaction for Pgm, Icd, Gly A, and Tyr B genes showed that all specimens have homogenous genes with a molecular weight of 500bp.
Conclusion: Evaluating the housekeeping genes in Bordetella pertussis vaccine strains by MLST vaccine strains (Razi Institute; Iran) correspond with international standard series and no change or deviation has occurred in the studied genes.