GENETIC CHARACTERIZATION OF Helicobacter pylori CULTURABLE COCCOID FORMS

MEDRANO MP, ; SALINAS AG, ; CORTIÑAS TI,; SILVA HJ, ; VEGA AE

San Juan

Congreso; 2da Reunión Conjunta de Sociedades de Biología de la República Argentina; 2011

Sociedad de Biología de Cuyo

Morphological conversion from spiral to coccoid forms has been described for Helicobacter pylori under several conditions such as aerobiosis alkaline pH, prolonged incubation and treatment with a proton pump inhibitor or antibiotics. Coccoid form has been considered as viable but non-culturable form of the bacterium. The aim of this study was to establish the culturability of coccoid forms and to characterize DNA and ribosomal RNA (rRNA). H. pylori NCTC 11638 reference strain and two clinical isolates were used to obtain coccoid forms under aerobic conditions. These forms were subcultured using Mueller Hinton agar supplemented with 7% horse blood. DNA and RNA from H. pylori bacillary and coccoid forms were isolated by rapid boiling and Trizol methods respectively. The results demonstrate that coccoid forms obtained from the three strains can be subcultured in vitro under adequate conditions. The coccoid forms showed distinct highly specific fragmentation patterns in both DNA and rRNA molecules. The cleavage pattern presumably reflects a predetermined physiological process in response to environmental conditions. From our data, the non-random fragmentation of DNA and rRNA in H. pylori does not induce loss of viability and coccoid forms can maintain transcriptional and translational processes.