Evolution, epidemiology and diversity of Corynebacterium diphtheriae: New perspectives on an old foe.
Diphtheria is a debilitating disease caused by toxigenic Corynebacterium diphtheriae strains and has been effectively controlled by the toxoid vaccine, yet several recent outbreaks have been reported across the globe. Moreover, non-toxigenic C. diphtheriae strains are emerging as a major global health concern by causing severe pharyngitis and tonsillitis, endocarditis, septic arthritis and osteomyelitis. Molecular epidemiological investigations suggest the existence of outbreak-associated clones with multiple genotypes circulating around the world. Evolution and pathogenesis appears to be driven by recombination as major virulence factors, including the tox gene and pilus gene clusters, are found within genomic islands that appear to be mobile between strains. The number of pilus gene clusters and variation introduced by gain or loss of gene function correlate with the variable adhesive and invasive properties of C. diphtheriae strains. Genomic variation does not support the separation of C. diphtheriae strains into biovars which correlates well with findings of studies based on multilocus sequence typing. Genomic analyses of a relatively small number of strains also revealed a recombination driven diversification of strains within a sequence type and indicate a wider diversity among C. diphtheriae strains than previously appreciated. This suggests that there is a need for increased effort from the scientific community to study C. diphtheriae to help understand the genomic diversity and pathogenicity within the population of this important human pathogen.
Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, UK.
Vartul
V
Sangal
Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK. Electronic address: Paul.hoskisson@strath.ac.uk.
Paul A
PA
Hoskisson
D005075:Biological Evolution; D002999:Clone Cells; D003353:Corynebacterium diphtheriae / Q000235:genetics* / Q000472:pathogenicity; D004165:Diphtheria / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control / Q000635:transmission; D004168:Diphtheria Toxoid / Q000008:administration & dosage; D004196:Disease Outbreaks; D014644:Genetic Variation; D016680:Genome, Bacterial; D044404:Genomic Islands; D005838:Genotype; D006801:Humans; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
D004168:Diphtheria Toxoid; D037521:Virulence Factors
Biovar; Corynebacterium diphtheriae; Evolution; MLST; Pathogenesis; Secreted proteins