title: Is Bordetella pertussis clonal?
abstract: OBJECTIVE
  To establish whether Bordetella pertussis is essentially clonal.
  
  
  METHODS
  Analysis of restriction fragments of XbaI digests of DNA from clinical and control isolates of B pertussis by pulse field gel electrophoresis.
  
  
  METHODS
  105 isolates of B pertussis: 67 clinical isolates from throughout the United Kingdom and 23 from Germany (collected during the previous 18 months); vaccine strains 2991 and 3700; and 13 control isolates from Manchester University's culture collection.
  
  
  METHODS
  Frequency of DNA types according to country of origin and classical serotyping.
  
  
  RESULTS
  17 DNA types were identified on the basis of the variation in 11 fragments, banding at 200-412 kilobases; 15 types were found in the clinical and control isolates from the United Kingdom and seven in those from Germany. There was no correlation with serotype. DNA type 1 was the commonest overall (22/105 strains, 22%), predominating in serotypes 1,2 and 1,2,3 and including the vaccine strains but not the isolates from Germany.
  
  
  CONCLUSIONS
  Current infections due to B pertussis are not caused by a clonal pathogen as multiple strains are circulating in a given population at one time. There is also considerable epidemiological variation in the pathogen population between countries. These findings may have implications for the design of acellular vaccines.
authors.affiliation: Department of Medical Microbiology, University of Manchester Medical School.
authors.forename: M N
authors.initials: MN
authors.lastname: Khattak
authors.forename: R C
authors.initials: RC
authors.lastname: Matthews
authors.forename: J P
authors.initials: JP
authors.lastname: Burnie
mesh_terms: D001886:Bordetella pertussis / Q000145:classification / Q000235:genetics*; D002999:Clone Cells; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis; D005838:Genotype; D012703:Serotyping
chemical_list: D004269:DNA, Bacterial