Relationship between cytotoxic necrotizing factor production and serotype in hemolytic Escherichia coli

A. Caprioli, V. Falbo, F. M. Ruggeri, F. Minelli, I. Orskov, G. Donelli

Research output: Contribution to journalArticlepeer-review


We examined the relationship between serotype and cytotoxic necrotizing factor (CNF) production in 123 hemolytic strains of Escherichia coli isolated from both stools and extraintestinal infections. Of 76 strains producing both hemolysin (Hly) and CNF, 66 (87%) belonged to one of six serogroups (02, 04, 06, 022, 075, and 083). In contrast, 47 E. coli strains producing Hly only belonged to 21 different 0 serogroups, and only 2 of these (06 and 018ac) were widely represented. Generally, CNF-positive and CNF-negative hemolytic isolates were assigned to different 0 serogroups, with the exception of 06, often present in both categories of isolates. Serogroups 04 and 018ac were significantly more prevalent among strains from extraintestinal infections than among those from stools. In contrast, the Hly-positive, CNF-negative isolates, belonging to numerous less common serogroups, were hardly ever isolated from extraintestinal infections. Serological typing further confirmed that hemolytic isolates of E. coli may grossly be divided into two main populations on the basis of the ability to produce CNF. Examination of hemolytic E. coli for this property may also be useful in achieving a more detailed characterization of pathogenic clones.

Original languageEnglish
Pages (from-to)758-761
Number of pages4
JournalJournal of Clinical Microbiology
Issue number4
Publication statusPublished - 1989

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)


Dive into the research topics of 'Relationship between cytotoxic necrotizing factor production and serotype in hemolytic Escherichia coli'. Together they form a unique fingerprint.

Cite this