mRNA cnf1 detection for monitoring viability and pathogenicity in an uropathogenic Escherichia coli J96 maintained in laboratory seawater microcosm

Author: Denden Ikbel ^*, Mahdouani Kassem, Ben Chibani Jemni and Bakhrouf Amina

Received 18 January 2004, accepted 22 April 2004.

Abstract

The seawater effects on persistence of necrotizing Escherichia coli (NTEC) pathogenicity were studied using an uropathogenic strain, Escherichia coli J96, previously incubated for 24 hours in waste water at stationary phase of growth. Using PCRessais, we have found that E.coli J96 strains exposed for long periods in seawater retained cnf1 gene. This gene was also expressed during the viable state in laboratory microcosms through detection of E.coli cnf1 mRNA by reverse transcription-PCR over a 5-month period. Maintenance of E.coli J96 pathogenicity was shown even when the culture returned to active growth in restored optimal conditions. The presence of cnf1 mRNA at viable state (culturable and VBNC) and in resuscitated cells correlating with cytotoxic activity on HEp2 cells and necrotic activity in rabbit skin, indicated the viability and the maintenance of pathogenicity during E.coli J96 incubation in seawater microcosms.