title: Application of pulsed field gel electrophoresis to the 1993 epidemic of whooping cough in the UK.
abstract: The purpose of this study was to DNA fingerprint the majority (64%) of isolates received at the Pertussis Reference Laboratory during the 1993 whooping cough epidemic by pulsed field gel electrophoresis of Xba I-generated restriction digests. Two DNA restriction patterns, types 1 and 3, predominated (40% and 23%, respectively, of 180 isolates) but type 2, identified in a previous study was notably absent. Twenty-one new DNA types occurred (24% of isolates), some being atypical as bands 155-230 kb were no longer conserved, but there was no statistically significant difference in their incidence in the upswing (June-September) compared to the downswing (October-December) phase of the epidemic. There was a relatively high proportion of new types, compared to type 1, at the peak (September). About 50% of isolates received were from the North Western Region, where 44% of isolates were DNA type 1. Whereas only 1 out of 10 isolates from Scotland were of this type, suggesting some geographic variation. Statistically significant findings included a higher proportion of isolates from female patients (P < 0.01), most marked in the 12-24 months age group (P < 0.05); a higher proportion of infants under 12 months requiring hospital admission compared to older children (P < 0.05); and a greater number of isolates from unvaccinated children (P < 0.01). Analysis of serotype according to four age groups (under 3 months, 3-12 months, 12-24 months and above 2 years) showed statistically significant differences (P < 0.05) with a noticeably lower proportion (38%) of serotype 1,3 in 3-12 months age group and higher prevalence (74%) of serotype 1,3 in the 12-24 months age group. There was no correlation between DNA type and serotype.
authors.affiliation: Department of Medical Microbiology, Manchester Royal Infirmary.
authors.forename: S N
authors.initials: SN
authors.lastname: Syedabubakar
authors.forename: R C
authors.initials: RC
authors.lastname: Matthews
authors.forename: N W
authors.initials: NW
authors.lastname: Preston
authors.forename: D
authors.initials: D
authors.lastname: Owen
authors.forename: V
authors.initials: V
authors.lastname: Hillier
mesh_terms: D000367:Age Factors; D001886:Bordetella pertussis / Q000145:classification* / Q000235:genetics; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000145:classification; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D012621:Seasons; D012703:Serotyping; D006113:United Kingdom / Q000453:epidemiology; D014917:Whooping Cough / Q000453:epidemiology* / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial