High Prevalence of Antibiotic Resistance in Iranian Helicobacter pylori Isolates: Importance of Functional and Mutational Analysis of Resistance Genes and Virulence Genotyping

Abstract

The high prevalence of antibiotic resistance in Helicobacter pylori has become a great challenge in Iran. The genetic mutations that contribute to the resistance have yet to be precisely identified. This study aimed to investigate the prevalence of antibiotic resistance and virulence markers in Iranian H. pylori isolates and to analyze if there is any association between resistance and genotype. Antibiotic susceptibility patterns of 68 H. pylori isolates were investigated against metronidazole, clarithromycin, amoxicillin, rifampicin, ciprofloxacin, levofloxacin, and tetracycline by the agar dilution method. The frxA, rdxA, gyrA, gyrB, and 23S rRNA genes of the isolates were sequenced. The virulence genotypes were also determined using PCR. Metronidazole resistance was present in 82.4% of the isolates, followed by clarithromycin (33.8%), ciprofloxacin (33.8%), rifampicin (32.4%), amoxicillin (30.9%), levofloxacin (27.9%), and tetracycline (4.4%). Overall, 75% of the isolates were resistant to at least two antibiotics tested and considered as a multidrug resistance (MDR) phenotype. Most of the metronidazole-resistant isolates carried frameshift mutations in both frxA and rdxA genes, and premature termination occurred in positions Q5Stop and Q50Stop, respectively. Amino acid substitutions M191I, G208E, and V199A were predominantly found in gyrA gene of fluoroquinolone-resistant isolates. A2143G and C2195T mutations of 23S rRNA were found in four clarithromycin-resistant isolates. Interestingly, significant associations were found between resistance to metronidazole (MNZ) and cagA-, sabA-, and dupA-positive genotypes, with p = 0.0002, p = 0.0001, and p = 0.0001, respectively. Furthermore, a significant association was found between oipA “on” status and resistance to amoxicillin (AMX) (p = 0.02). The prevalence of H. pylori antibiotic resistance is high in our region, particularly that of metronidazole, clarithromycin, ciprofloxacin, and MDR. Simultaneous screening of virulence and resistance genotypes can help clinicians to choose the appropriate therapeutic regime against H. pylori infection.

Characterization and genetic diversity of Helicobacter pylori type IV secretion system components CagI and CagN and their association with clinical outcomes among Iranian patients

“…In the preset study, we also investigated the presence of various H. pylori virulence genotypes. In accordance with our previous studies in Iranian populations, we detected a high prevalence of vacA s1 (77.1%) and vacA m2 (65.7%) allelic genotypes [38,39]. The vacA s1 allele has been reported to be associated with more severe atrophic gastritis in peptic ulcer patients [40,41].…”

Novel virulence factor dupA of Helicobacter pylori as an important risk determinant for disease manifestation: An overview

“…Recently, Fatahi et al[ 32 ] (2019) tested a highly conserved region of dupA and showed a significant relationship between the occurrence of DU and the presence of an 112 bp segment of dupA in the Iranian population[ 32 ]. Another group from Iran studied the relationship between antibiotic resistance pattern and virulence genotype among 68 H. pylori strains and found that metronidazole resistance was significantly associated with the strains harboring cagA, sabA and dupA [ 33 ]. One study from Kurdistan region of Northern Iraq reported that cagA gene was significantly associated with peptic ulcer disease rather than dupA , which contradict the result of Hussein et al[ 29 ] (2008).…”

The increasing antimicrobial resistance of Helicobacter pylori in Iran: A systematic review and meta‐analysis

“…From the 131 articles, 65 were excluded for the following reasons: meta‐analysis, review, non‐original research, conference abstract and article without full text (n = 55), and non‐relevant data or no data for susceptibility testing or no resistance data (n = 10). Finally, 66 studies 4,16‐80 were included in this systematic review and meta‐analysis (Supplementary Table ).…”