Biologia, Bratislava, 56/Suppl. 9: 75-79, 2001.

ISSN 0006-3088 (Biologia). ISSN 1335-6399 (Biologia. Section Cellular and Molecular Biology).


Full Paper

Detection of necrotoxigenic type 1 Escherichia coli (NTEC1) strains: comparison of phenotypic and genotypic methods.


Eva Bogyiova*, Leonard Siegfried, Marta Kmetova, Hana Kerestesová, Zuzana Sandorcinová & Adriana Liptakova

Institute of Medical Microbiology, Faculty of Medicine, Pavol Jozef Safarik University, Srobarova 2, SK-04180 Kosice, Slovakia; tel.: ++ 421 95 6225471, e-mail:

* corresponding author

Received: February 9, 2001 / Accepted: April 23, 2001



Necrotoxigenic (NTEC) Escherichia coli (E. coli) strains can produce two types of cytotoxic necrotizing factors (CNFs) - CNF1 and CNF2. These toxins are heat-labile monomeric proteins of 115 and 110 kDa respectively and they are immunologically related. Considering the clinical significance of the CNF1-producing E. coli (NTEC1) strains, rapid, specific, and sensitive detection method is required to identify these isolates. The main aim of this study was to evaluate sensitivity and specificity of indirect immunofluorescent assay (as a phenotypic method) and PCR (as a genotypic method) used for detection of necrotoxigenic E. coli strains. Our results indicate, that PCR method is more reliable for detection of NTEC1 strains than phenotype-based methods.


Key words: CNF1, necrotoxigenic, Escherichia coli.