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 by demonstrating the integrity of the DNA and active protein synthesis, we analysed the expression of ureA, cagA, vacA genes after prolonged incubation in a liquid medium. Exponentially growing and ageing phase cultures were used. Our results showed that, although the coccoid forms had decreased DNA and RNA levels after 31 days, they were not degraded and still expressed the urease, cytotoxic island and vacuolating toxin genes. Coccoid forms are therefore viable and may act as a transmissible agent that plays a crucial role in disease relapses after antibiotic therapy.
Istituto di Microbiologia Medica, Università degli Studi di Milano, Milan, Italy.
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D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D018076:DNA, Complementary; D005798:Genes, Bacterial; D016480:Helicobacter pylori / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D017931:DNA Primers; D018076:DNA, Complementary; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori