title: Isolation of High Level Macrolide Resistant Bordetella pertussis Without Transition Mutation at Domain V in Iran.
abstract: BACKGROUND
  Bordetella pertussis, as a causative agent of whooping cough, due to the annual rise y of infection cases, failure of prophylaxis and treatment by macrolides, is considered as the new concern in the health care system.
  
  
  OBJECTIVE
  The main objective of this study was the determination of single nucleotide polymorphisms (SNPs) at domain V, as the main binding site for macrolides, following the identification of high level macrolides resistant B. pertussis.
  
  
  METHODS
  Following the identification of 11 recovered B. pertussis isolates, from a total of 1084 nasopharyngeal swabs, by using the biochemical and molecular methods, the activities of erythromycin, azithromycin and clarithromycin antibiotics against the recovered isolates were examined. Subsequently, A-G transition mutations in domain V were analyzed by molecular techniques, such as Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and sequencing.
  
  
  RESULTS
  After susceptibility testing, one strain was detected as a high level macrolide resistant B. pertussis (Erythromycin = 128 μg/mL, Clarithromycin > 256 μg/mL). After sequencing and PCR-RFLP methods, transition mutations in positions 2047 and 2058 of the mentioned domain were not observed.
  
  
  CONCLUSIONS
  Although previous studies have shown that A-G transition mutations in 23 SrRNA gene (domain V) are the main reason for the occurrence of high level macrolides resistance in B. pertussis, however, the mentioned single nucleotide polymorphisms (SNPs) have not been detected in our resistant strain. This is the first report of high level macrolide resistant B. pertussis, without SNPs in domain V, in Iran.
authors.affiliation: Department of Bacteriology, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Bahman
authors.initials: B
authors.lastname: Mirzaei
authors.affiliation: Department of Bacteriology, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Zakaria
authors.initials: Z
authors.lastname: Bameri
authors.affiliation: Department of Bacteriology, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Ryhane
authors.initials: R
authors.lastname: Babaei
authors.affiliation: Department of Bacteriology, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Shahcheraghi
keywords: Bordetella pertussis; Drug Resistance, Minimum Inhibitory Concentration; Macrolides; Mutation