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, 19 (1), 546

Genotypic Determination of Resistance and Heteroresistance to Clarithromycin in Helicobacter Pylori Isolates From Antrum and Corpus of Colombian Symptomatic Patients

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Genotypic Determination of Resistance and Heteroresistance to Clarithromycin in Helicobacter Pylori Isolates From Antrum and Corpus of Colombian Symptomatic Patients

Betsy Verónica Arévalo-Jaimes et al. BMC Infect Dis.

Abstract

Background: The effectiveness of Helicobacter pylori first-line treatment has decreased drastically with the rise of strains resistant to clarithromycin. Therapy failure has also been described in patients with infections by strains with dissimilar antimicrobial susceptibilities. The present study aims to estimate the prevalence of resistance and heteroresistance to clarithromycin in H. pylori isolates from antrum and corpus of Colombian patients.

Methods: The study material included 126 isolates from antrum and corpus biopsies from 63 symptomatic patients over 18 years old who had a gastric endoscopy performed on them between June 2014 to August 2016. PCR amplification and sequencing of the H. pylori 23S rDNA gene was performed to determine the presence of mutations associated with clarithromycin resistance. Random amplified polymorphic DNA analysis was implemented in cases of resistance and heteroresistance.

Results: The overall frequency of resistance to clarithromycin was 38.1% (24/63 patients), of which 19 patients had resistant isolates in both stomach segments (14 with A2143G mutation and 5 with A2142G mutation), and 5 patients had a heteroresistant status. The remaining 61.9% (39/63 patients) presented only susceptible isolates. DNA fingerprinting analysis showed different patterns in 4/22 paired isolates.

Conclusions: The high prevalence of H. pylori clarithromycin-resistance obtained (> 15%) constitutes an alert for gastroenterologists and suggests the need for reconsideration of the current eradication regimen for H. pylori in the studied population. The data show that heteroresistance status is an additional factor to be considered in the assessment of resistance. In consequence, it is advisable to examine at least two biopsies from different gastric segments.

Keywords: Clarithromycin; Eradication; Helicobacter pylori; Heteroresistance; Resistance.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Study Profile. Flowchart of the selection process of the study sample and their distribution per H. pylori 23S rDNA status
Fig. 2
Fig. 2
PCR products for a 267 bp region of the 23S rDNA gene of Helicobacter pylori. 2% (w/v) Agarose gel. Line 1–9: Bacterial samples. Line 10: Blank of reaction. Line 11: Positive control Helicobacter pylori NCTC 11637. Line 12: 100 bp Leader
Fig. 3
Fig. 3
RAPD-PCR fingerprinting patterns of Helicobacter pylori isolates in three heteroresistance cases. It can be seen when the isolate belonged to antrum (A) or corpus (B). M: Molecular size marker. C-: Blank of reaction. Different patterns are only observed in patient 293
Fig. 4
Fig. 4
RAPD-PCR fingerprinting patterns of Helicobacter pylori in resistance cases. It can be seen when the isolate belonged to antrum (A) or corpus (B). M: Molecular size marker. C-: Blank of reaction. Patients 94, 130, 151, 153, 163, 200, 219, 230, 251, 318, 329, 351, 359 and 374 show identical DNA profiles. Patients 91 and 170 show similar patterns. Patients 51, 98 and 164 show different DNA profiles

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