Genetic heterogeneity of M type 3 group A streptococci causing severe infections in Tayside, Scotland.
To explain the worldwide increase in the frequency of severe infections by group A streptococci, molecular techniques are increasingly being employed to evaluate the genetic relationships of strains. We used restriction endonuclease analysis, pulsed-field gel electrophoresis (PFGE), the PCR, ribotyping, and DNA sequence analysis in a study of 13 group A streptococci isolated from a cluster of cases of serious infections over a 3-month period in Tayside, Scotland. Eight of the strains were M type 3; molecular characterization identified two subclones. The first, displaying PFGE profile 4, has been observed in Northern Scotland and has been circulating in New Zealand for over a decade. The second subclone has been documented only in the United Kingdom; it was first seen in 1993 in Scotland. Sequence analysis of emm-3 genes further differentiated the PFGE 4 subclone. DNA sequence analysis of virulence factors supports the suggestion that they may have recently been acquired by horizontal gene transfer.
Upton
M
M
Department of Medical Microbiology, University of Aberdeen, Scotland.
Carter
P E
PE
Orange
G
G
Pennington
T H
TH
D015373:Bacterial Typing Techniques; D001483:Base Sequence; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012606:Scotland / Q000453:epidemiology; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
D017931:DNA Primers; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes