Helicobacter pylori: ureA, cagA and vacA expression during conversion to the coccoid form

As viability of coccoid forms of Helicobacter pylori can only be verified b y demonstrating the integrity of the DNA and active protein synthesis, we a nalysed the expression of ureA, cagA, vacA genes after prolonged incubation in a liquid medium. Exponentially growing and ageing phase cultures were u sed. Our results showed that, although the coccoid forms had decreased DNA and RNA levels after 31 days, they were not degraded and still expressed th e urease, cytotoxic island and vacuolating toxin genes. Coccoid forms are t herefore viable and may act as a transmissible agent that plays a crucial r ole in disease relapses after antibiotic therapy. (C) 2000 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.