The First Macrolide-Resistant Bordetella pertussis Strains Isolated From Iranian Patients

BACKGROUND Whooping cough was considered as one of the major causes of childhood morbidity and mortality worldwide. Resistant isolates of Bordetella pertussis to macrolides in some countries have been recently reported. OBJECTIVES Recent reports on macrolide-resistant B. pertussis isolates and lack of evidence for such resistance in clinical isolates of the Iranian patients led the authors of the current study to study antibiotic susceptibility of the collected isolates in the country. Susceptibility of the B. pertussis isolates to three antibiotics was studied. Relatedness of the strains recovered in this research was also examined. MATERIALS AND METHODS The antibacterial activities of erythromycin, azithromycin, and clarithromycin antibiotics against the recovered isolates of 779 nasopharyngeal swabs were examined using MIC (Minimum Inhibitory Concentration) method. Relationship of the strains was characterized by Pulsed-field Gel Electrophoresis (PFGE). RESULTS Among the specimens, 11 cases (1.4%) were culture-positive. Among these isolates, only two isolates had high MIC values for erythromycin and clarithromycin. Pulsed-field gel electrophoresis analysis of the isolates revealed 6 PFGE profiles (A-F) among which three and two isolates had the same patterns in profiles A and B, respectively. CONCLUSIONS Azithromycin can be a good drug of choice to treat patients infected by B. pertussis in Iran. Clonal relationship of the isolates showed that the same B. pertussis strains were isolated from different patients in Iran.