Low Helicobacter pylori primary resistance to clarithromycin in gastric biopsy specimens from dyspeptic patients of a city in the interior of São Paulo, Brazil

Suzuki, Rodrigo Buzinaro; Lopes, Rodrigo Augusto Basso; Lopes, George Arouche da Câmara; Ho, Tin Hung; Sperança, Márcia Aparecida

doi:10.1186/1471-230x-13-164

Cited by 23 publications

(22 citation statements)

References 46 publications

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“…The cycling conditions were as follows; denaturation at 94 °C 5 min followed by 40 cycles at 94 °C for 30 sec; 60 °C for 30 sec; 72 °C for 30 sec and one final extension cycle at 72 °C for 7 min, in a total volume of 25 µL containing 1× PCR buffer, 200 µM dNTPs, 2.0 mM MgCl2, 1 µM of each oligonucleotide primer, 1.25 U Taq DNA according to Suzuki et al . 2013 9 .…”

Section: Methodsmentioning

confidence: 99%

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GENETIC MUTATIONS AFFECTING THE FIRST LINE ERADICATION THERAPY OF Helicobacter pylori-INFECTED EGYPTIAN PATIENTS

Ramzy

El-Garem

Hamza

et al. 2016

Rev. Inst. Med. trop. S. Paulo

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SUMMARYIntroduction: Several genetic mutations affect the first-line triple therapy for Helicobacter pylori. We aimed to study the most common genetic mutations affecting the metronidazole and clarithromycin therapy for H. pylori-infected Egyptian patients.Patients and Methods: In our study, we included 100 successive dyspeptic patients scheduled for diagnosis through upper gastroscopy at Cairo's University Hospital, Egypt. Gastric biopsies were tested for the presence of H. pylori by detection of the 16S rRNA gene. Positive biopsies were further studied for the presence of the rdxA gene deletion by Polymerase Chain Reaction (PCR), while clarithromycin resistance was investigated by the presence of nucleotide substitutions within H. pylori 23S rRNA V domain using MboII and BsaI to carry out a Restricted Fragment Length Polymorphism (RFLP) assay.Results: Among 70 H. pylori positive biopsies, the rdxA gene deletion was detected in 44/70 (62.9%) samples, while predominance of the A2142G mutations within the H. pylori 23S rRNA V domain was evidenced in 39/70 (55.7%) of the positive H. pylori cases. No statistically significant difference was found between the presence of gene mutations and different factors such as patients 'age, gender, geographic distribution, symptoms and endoscopic findings.Conclusion: Infection with mutated H. pylori strains is considerably high, a finding that imposes care in the use of the triple therapy to treat H. pylori in Egypt, since the guidelines recommend to abandon the standard triple therapy when the primary clarithromycin resistance rate is over 20%1.

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Section: Methodsmentioning

confidence: 99%

“…These restriction enzymes are able to discriminate mutations within the H. pylori domain V of the 23S rDNA at positions 2,142 and 2,143, respectively 9 .…”

Section: Methodsmentioning

confidence: 99%

GENETIC MUTATIONS AFFECTING THE FIRST LINE ERADICATION THERAPY OF Helicobacter pylori-INFECTED EGYPTIAN PATIENTS

Ramzy

El-Garem

Hamza

et al. 2016

Rev. Inst. Med. trop. S. Paulo

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“…Camargo et al (23) suggest in their meta-analysis that the empirical use of clarithromycin may be inappropriate in Peru and Colombia (23) . In Brazil, H. pylori clarithromycin resistance shows high prevalence, with rates of 7-16% in adults and 27% in children (24) . The metronidazole resistance of H. pylori is closely related to geographic location and to the use of this drug for its antiparasitic activity.…”

Section: Ethical Considerationsmentioning

confidence: 99%

Antimicrobial resistance of Helicobacter pylori strains to five antibiotics, including levofloxacin, in Northwestern Turkey

Caliskan

Tokman

Erzın

et al. 2015

Rev. Soc. Bras. Med. Trop.

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Introduction: Antibiotic resistance is the main factor that affects the effi cacy of current therapeutic regimens against Helicobacter pylori. This study aimed to determine the rates of resistance to effi cacy clarithromycin, amoxicillin, tetracycline, levofl oxacin and metronidazole among H. pylori strains isolated from Turkish patients with dyspepsia. Methods: H. pylori was cultured from corpus and antrum biopsies that were collected from patients with dyspeptic symptoms, and the antimicrobial susceptibility of H. pylori was determined using the E-test (clarithromycin, amoxicillin, tetracycline, metronidazole and levofl oxacin) according to the EUCAST breakpoints. Point mutations in the 23S rRNA gene of clarithromycin-resistant strains were investigated using realtime PCR. Results: A total of 98 H. pylori strains were isolated, all of which were susceptible to amoxicillin and tetracycline. Of these strains, 36.7% (36/98) were resistant to clarithromycin, 35.5% (34/98) were resistant to metronidazole, and 29.5% (29/98) were resistant to levofl oxacin. Multiple resistance was detected in 19.3% of the isolates. The A2143G and A2144G point mutations in the 23S rRNA-encoding gene were found in all 36 (100%) of the clarithromycin-resistant strains. Additionally, the levofl oxacin MIC values increased to 32 mg/L in our H. pylori strains. Finally, among the clarithromycin-resistant strains, 27.2% were resistant to levofl oxacin, and 45.4% were resistant to metronidazole. Conclusions: We conclude that treatment failure after clarithromycin-or levofl oxacinbased triple therapy is not surprising and that metronidazole is not a reliable agent for the eradication of H. pylori infection in Turkey.

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“…It is important as a premise for consideration of more rational antibiotic combinations. One mechanism of CAM resistance has been elucidated due to one of five well-known point mutations (A2142G, A2143G, A2142C, A2144T, T2717C and C2694A) in the 23SrRNA [6, 7]. Our previous report demonstrated higher MICs associated with the synergic effect of mutated sequences in infB ( hp1048 ), rpl22 ( hp1314 ) and A2143G [8].…”

Section: Introductionmentioning

confidence: 99%

Emerging Helicobacter pylori levofloxacin resistance and novel genetic mutation in Nepal

et al. 2016

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BackgroundThe prevalence of Helicobacter pylori antibiotic susceptibility in the Nepalese strains is untracked. We determined the antibiotic susceptibility for H. pylori and analyzed the presence of genetic mutations associated with antibiotic resistance in Nepalese strains.ResultsThis study included 146 consecutive patients who underwent gastroduodenal endoscopy in Kathmandu, Nepal. Among 42 isolated H. pylori, there was no resistance to amoxicillin and tetracycline. In contrast, similar with typical South Asian patterns; metronidazole resistance rate in Nepalese strains were extremely high (88.1 %, 37/42). Clarithromycin resistance rate in Nepalese strains were modestly high (21.4 %, 9/42). Most of metronidazole resistant strains had highly distributed rdxA and frxA mutations, but were relative coincidence without a synergistic effect to increase the minimum inhibitory concentration (MIC). Among strains with the high MIC, 63.6 % (7/11) were associated with frameshift mutation at position 18 of frxA with or without rdxA involvement. However, based on next generation sequencing data we found that one strain with the highest MIC value had a novel mutation in the form of amino acid substituted at Ala-212, Gln-382, Ile-485 of dppA and Leu-145, Thr-168, Glu-117, Val-121, Arg-221 in dapF aside from missense mutations in full-length rdxA. Mutations at Asn-87 and/or Asp-91 of the gyrA were predominantly in levofloxacin-resistant strains. The gyrB mutation had steady relationship with the gyrA 87–91 mutations. Although three (44.4 %) and two (22.2 %) of clarithromycin resistant strains had point mutation on A2143G and A2146G, we confirmed the involvement of rpl22 and infB in high MIC strains without an 23SrRNA mutation.ConclusionsThe rates of resistance to clarithromycin, metronidazole and levofloxacin were high in Nepalese strains, indicating that these antibiotics-based triple therapies are not useful as first-line treatment in Nepal. Bismuth or non-bismuth-based quadruple regimens, furazolidone-based triple therapy or rifabutin-based triple therapy may become alternative strategy in Nepal.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0873-6) contains supplementary material, which is available to authorized users.

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Low Helicobacter pylori primary resistance to clarithromycin in gastric biopsy specimens from dyspeptic patients of a city in the interior of São Paulo, Brazil

Cited by 23 publications

References 46 publications

GENETIC MUTATIONS AFFECTING THE FIRST LINE ERADICATION THERAPY OF Helicobacter pylori-INFECTED EGYPTIAN PATIENTS

GENETIC MUTATIONS AFFECTING THE FIRST LINE ERADICATION THERAPY OF Helicobacter pylori-INFECTED EGYPTIAN PATIENTS

Antimicrobial resistance of Helicobacter pylori strains to five antibiotics, including levofloxacin, in Northwestern Turkey

Emerging Helicobacter pylori levofloxacin resistance and novel genetic mutation in Nepal

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