Prevalence of antibiotic resistance in Helicobacter pylori: A recent literature review

Table 1 Mode of action, resistance mechanisms of antimicrobial agents used for treatment of Helicobacter pylori infection

Antibiotic	Mode of action	Resistance mechanisms
Metronidazole	Electron reduction processes, leads to the formation of nitro-anion radicals and subsequent DNA damage	(1) Poor drug uptake and/or increased drug efflux; (2) enhanced activity of DNA repair enzymes; (3) increased oxygen scavenging abilities; and (4) decreased antibiotic activation arising from changes in metronidazole-reducing enzymes[16]
Clarithromycin	The inhibition of protein synthesis by binding and slowing down the activity of the bacterial ribosomal unit[17]	rRNA-point mutations
Amoxicillin	The inhibition cell wall synthesis	pbp gene mutations, membrane permeability alterations and efflux pumps[17]
Tetracycline	Reversible inhibition protein synthesis	Three contiguous nucleotides mutation in the 16S rRNA gene[17]
Fluoroquinolones	Inhibiting DNA gyrase, type II topoisomerase, and topoisomerase IV[17]	Point mutations in the quinolones resistance determining regions
Rifabutin	Inhibits the b-subunit of H. pylori DNA-dependent RNA polymerase encoded by the rpoB gene[18]	Mutation of the rpoB gene[18]

H. pylori: Helicobacter pylori.