title: Molecular epidemiology of Bordetella pertussis isolated in Taiwan, 1992-1997.
abstract: In Taiwan, the number of pertussis cases including various types of infection has been increasing in recent years, especially in 1997. Since 71% of the reported cases concentrated in the densely populated Taipei metropolitan area, concerns have been raised that a highly contagious strain of Bordetella pertussis might have appeared in Taipei. In this study, 114 strains of B. pertussis including those isolated in 1992-1996 (n = 53) and 1997 (n = 61) were subjected to pulsed-field gel electrophoresis (PFGE) of the Xba I digests from their chromosomes. Based on the band patterns, they were divided into 21 subtypes, P1 to P21. The strains isolated in 1997 consist of 17 subtypes including 9 new subtypes which did not appear in the previous years, indicating that the outbreaks in 1997 were not caused by a sole specific virulent strain. Dendrogram analysis indicated that the 21 subtypes can be grouped into five clusters, with the first four subtypes possessing 60 to 95% relatedness to one another, whereas relatedness between cluster 5 (containing P21 only) and the other clusters is less than 50%. Notably, all the subtypes except P12 and P21 appeared at least once in Taipei and the majority of the strains (54%) belong to two clusters, 3 and 4. These results suggest that highly dense population may facilitate spread and accelerate genetic divergence of this pathogen. This is the first report on pertussis molecular epidemiology in Taiwan.
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Yeong-Sheng
authors.initials: YS
authors.lastname: Lee
authors.forename: Chiou-Ying
authors.initials: CY
authors.lastname: Yang
authors.forename: Cheng-Hsiung
authors.initials: CH
authors.lastname: Lu
authors.forename: Yi-Hsiung
authors.initials: YH
authors.lastname: Tseng
mesh_terms: D015373:Bacterial Typing Techniques; D001886:Bordetella pertussis / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D002876:Chromosomes, Bacterial / Q000737:chemistry; D016000:Cluster Analysis; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans; D017720:Molecular Epidemiology / Q000379:methods; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D013624:Taiwan / Q000453:epidemiology; D014917:Whooping Cough / Q000453:epidemiology* / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes; C025580:endodeoxyribonuclease XBAI; D015252:Deoxyribonucleases, Type II Site-Specific