Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics.
AIM
To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared.


METHODS
A collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction (PCR) reaction with HP1165 and hp1165 efflux pump genes. Susceptibilities of the selected strains to antibiotic and differences between susceptibilities of planktonic and biofilm-forming cell populations were determined. Quantitative real-time PCR (qPCR) analysis was performed using 16S rRNA gene as a H. pylori-specific primer, and two efflux pumps-specific primers, hp1165 and hefA.


RESULTS
The strains were resistant to amoxicillin, metronidazole, and erythromycin, except for one strain, but they were all susceptible to tetracycline. Minimum bactericidal concentrations of antibiotics in the biofilm-forming cells were significantly higher than those of planktonic cells. qPCR demonstrated that the expression of efflux pump genes was significantly higher in the biofilm-forming cells as compared to the planktonic ones.


CONCLUSION
The present work demonstrated an association between H. pylori biofilm formation and decreased susceptibility to all the antibiotics tested. This decreased susceptibility to antibiotics was associated with enhanced functional activity of two efflux pumps: hp1165 and hefA.
['Attaran|Bahareh|B|', 'Falsafi|Tahereh|T|', 'Ghorbanmehr|Nassim|N|']
D000328:Adult D000658:Amoxicillin D000900:Anti-Bacterial Agents D018441:Biofilms D002648:Child D017291:Clarithromycin D024881:Drug Resistance, Bacterial D024901:Drug Resistance, Multiple, Bacterial D004917:Erythromycin D005798:Genes, Bacterial D016481:Helicobacter Infections D016480:Helicobacter pylori D006801:Humans D008795:Metronidazole D008826:Microbial Sensitivity Tests D012336:RNA, Ribosomal, 16S D060888:Real-Time Polymerase Chain Reaction D013752:Tetracycline
Biofilm Helicobacter pylori hp1165 Antibiotic resistance Efflux genes hefA