Helicobacter pylori biofilm: a protective environment for bacterial recombination.
OBJECTIVE
The aim of this work was to investigate the interaction between two Helicobacter pylori strains in promoting genetic transfer, when grown in the biofilm mode.


RESULTS
Biofilms produced by H. pylori 9/10 (A), H. pylori 15/4 (B) and their mixture (C) were studied for biomass production and cell viability. The genetic heterogeneity of 45 clones, coming from mature biofilm of co-cultured H. pylori strains was studied by both RAPD and cagA (EPIYA motifs)/vacA virulence genes analysis. Helicobacter pylori A, B and C developed a well-structured biofilm without significant differences in viability. No significant differences were recorded between A and B biomass measurement, whereas C biofilm expressed a significant (P < 0.001) higher adhesive capability when compared with A and B biofilms. C-clones DNA-fingerprintings showed an high genetic heterogeneity (mean similarity value = 0.528). The 60% of C-clones displayed vacA allelic combination s1i1m1m2 associated with cagA EPIYA motif pattern P1P2P3P3P3.


CONCLUSIONS
Biofilms developed by multiple H. pylori strains are more complex than those associated with single strains. Such condition might promote the genetic exchange favouring the generation of more virulent strains.


CONCLUSIONS
The 'biofilm niche' represents a successful strategy and a suitable environment for promoting bacterial population persistence by recombination events.
Department of Drug Sciences, University G. d'Annunzio, Chieti-Pescara, Italy.
R
R
Grande
E
E
Di Campli
S
S
Di Bartolomeo
F
F
Verginelli
M
M
Di Giulio
M
M
Baffoni
L J
LJ
Bessa
L
L
Cellini
D000942:Antigens, Bacterial / Q000235:genetics; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms; D018533:Biomass; D018920:Coculture Techniques; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005838:Genotype; D016480:Helicobacter pylori / Q000235:genetics* / Q000254:growth & development*; D050296:Microbial Viability; D019105:Random Amplified Polymorphic DNA Technique; D011995:Recombination, Genetic; D037521:Virulence Factors / Q000235:genetics
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori