Phagocytic resistance of Escherichia coli K-1 isolates and relationship to virulence.

Abstract

Blood culture isolates from 133 episodes of Escherichia coli bacteremia were typed for K-1 capsular antigen by immunodiffusion, utilizing equine antiserum raised against meningococcal group B polysaccharide. Twenty-six percent (34 of 133) of these isolates were positive for K-1 antigen. These 133 strains, 34 K-1 and 99 non-K-1, were tested for susceptibility to phagocytosis. K-1 strains were found to be more resistant to clearance (27%) than non-K-1 strains (71%) when tested in an in vitro opsonophagocytic/killing assay containing normal human granulocytes and plasma. Additional studies demonstrated that resistance was due to decreased phagocytosis rather than diminished intraleukocytic killing. K-1 strains obtained from stool showed a similar degree of resistance to phagocytosis when compared with K-1 blood isolates. A comparison of clinical data on non-neonatal patients with E. coli K-1 and non-K-1 bacteremia showed no significant differences in mortality for these two groups. The incidence of shock for patients bacteremic with K-1 strains (74%) was significantly greater than that for patients bacteremic with non-K-1 strains (33%). These differences are attributed to the increased resistance to phagocytosis observed for K-1 versus non-K-1 E. coli isolates.

• Authors: R Weinstein, L S Young
• Journal: Journal of clinical microbiology (J Clin Microbiol) Vol. 8 Issue 6 Pg. 748-55 (Dec 1978) ISSN: 0095-1137 [Print] United States
• PMID: 370149 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Polysaccharides, Bacterial

Topics

• Adult
• Blood (microbiology)
• Escherichia coli (immunology, pathogenicity)
• Feces (microbiology)
• Female
• Humans
• Male
• Middle Aged
• Neutrophils (immunology)
• Phagocytosis
• Polysaccharides, Bacterial
• Sepsis (microbiology)
• Shock, Septic (microbiology)
• Virulence