Restriction fragment length polymorphisms associated with alpha-hemolysin determinants are correlating with the expression of alpha-hemolysin in strains of Escherichia coli.
Three different phenotypes of hemolysis on blood-agar were detected when 58 isolates of Escherichia coli were investigated for alpha-hemolysin synthesis. In strains with chromosomally encoded alpha-hly genes, phenotype I (large and clear hemolysis zones) corresponded with high hemolytic activity and with a 17.2 kb size BamHI restriction fragment hybridizing with an alpha-hly-specific gene probe. Phenotype II (small and turbid hemolysis zones) was associated with low hemolytic activity and generally with a 12.8 kb size hybridizing BamHI restriction fragment. An intermediate phenotype (type I/II) was found in a few strains with moderate hemolytic activity. This correlation between hemolytic phenotype and activity was not found in E. coli carrying alpha-hly plasmids. Type I strains differed from all others in the promotor region of their 17.2 kb size BamHI fragment associated chromosomal alpha-hly determinant. The relation between hemolytic phenotype and DNA hybridization pattern was found in unrelated E. coli isolates of human and animal origin. An association of alpha-hemolysin with other virulence factors was found in most strains of all three phenotypes.
Robert Koch-Institut des Bundesgesundheitsamtes, Berlin.
J
J
Prada
S
S
Zimmermann
R
R
Stephan
L
L
Beutin
D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D015139:Blotting, Southern; D002417:Cattle; D003470:Culture Media; D015342:DNA Probes; D004269:DNA, Bacterial / Q000032:analysis*; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D006461:Hemolysis; D006801:Humans; D010641:Phenotype; D010957:Plasmids; D012150:Polymorphism, Restriction Fragment Length; D013552:Swine; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D003470:Culture Media; D015342:DNA Probes; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; C036507:Hlya protein, E coli