Co-Existence of Heterogene and Heteroresistance Helicobacter Pylori Strains in a Single Host

Parastoo Saniee, Marzieh Raoofimanesh, Farideh Siavoshi, Sara Kadkhodaee, Gelareh Poostizadeh



Helicobacter pylori (H. pylori) exhibits considerable genetic diversity, which contributes to adaptation to the new host, wide spread, and its ability to cause various gastrointestinal diseases. In this study, the possibility of the presence of H. pylori strains with different genetic and antibiotic resistance patterns in a single host was investigated.

Material and Methods:

Gastric biopsy samples of 10 H. pylori-positive patients were cultured on selective brucella agar and incubated microaerobically. Four single colonies per patient were picked from the primary culture and sub-cultured to obtain pure H. pylori isolates. Antibiotic susceptibility/resistance of primary culture, as well as pure H. pylori, isolates to nine common antibiotics in eradication (in MIC) was assessed by agar dilution method. Genotyping was performed by amplification of cagA and signal (s1 and s2) and middle (m1 and m2) regions of vacA genes.


Heteroresistance was observed in seven patients to tetracycline, in five patients to levofloxacin, in five patients to metronidazole, in three patients to ofloxacin, in five patients to rifampin, in two patients to furazolidone, in one patient to amoxicillin, and in one patient to clarithromycin.  Considering the cagA gene and vacA s and vacA m alleles, four patients carried H. pylori isolates with two different genotypes and three patients carried the isolates with three different genotypes.


The presence of heterogeneous and heteroresistance H. pylori strains in a single host can have a direct impact on the treatment outcome of the infection. In this regard, in order to have accurate information on H. pylori infection in each individual, sampling of several gastric areas along with examining of 3-10 single colonies from the primary culture is recommended.


Helicobacter pylori, Antibiotic resistance, Genetic diversity

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