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

Autor(es)

Suzuki, Rodrigo Buzinaro ^{[1, 2]} ; Basso Lopes, Rodrigo Augusto ^[1] ; da Camara Lopes, George Arouche ^[1] ; Ho, Tin Hung ^[3] ; Speranca, Marcia Aparecida ^{[2, 3]}

Afiliação do(s) autor(es)

^[1] Marilia Med Sch, Dept Mol Biol, Sao Paulo - Brazil

^[2] Univ Fed ABC, Ctr Nat & Human Sci, Sao Paulo - Brazil

^[3] Tin Hung Ho, Marilia Med Sch, Dept Mol Biol, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: BMC GASTROENTEROLOGY; v. 13, DEC 4 2013.
• Citações Web of Science: 13

Resumo

Background: Clarithromycin, amoxicillin, and a pump proton inhibitor are the most common drugs recommended as first-line triple therapy for H. pylori treatment, which results in eradication rates close to 80%, varying regionally, principally due to emergency cases and increases of clarithromycin resistant strains. Nucleotide substitutions at the H. pylori domain V of the 23S rRNA fraction are involved in the macrolide resistance and the A2142G and A2143G mutations are predominant in clinical isolates worldwide including in Brazil. As H. pylori culture is fastidious, we investigated the primary occurrence of H. pylori A2142G and A2143G rDNA 23S mutations using a molecular approach directly on gastric biopsies of dyspeptic patients consecutively attended at Hospital das Clinicas of Marilia, Sao Paulo, Brazil. Methods: Biopsy specimens obtained from 1137 dyspeptic patients, were subjected to histopathology and H. pylori diagnosis by histology and PCR. PCR/RFLP assay was used to detect A2142G and A2143G point mutations at domain V of the H. pylori 23S rDNA associated with clarithromycin resistance. Through the developed assay, a 768 bp PCR amplicon corresponding to 1728 to 2495 bp of the 23S H. pylori rDNA is restricted with MboII for A2142G mutation detection and with BsaI for A2143G mutation detection. Occurrence of 23S rDNA A2142G results in two DNA fragments (418 and 350 bp) and of 23S rDNA A2143G results in three DNA fragments (108, 310 and 350pb), due to a conserved BsaI restriction site. Results: The PCR method used to diagnose H. pylori presented sensitivity, specificity and accuracy of 77,6%, 79,3% and 78,6%, respectively, compared to histology, the gold standard method for H. pylori diagnosis used in our routine. Prevalence of H. pylori with clarithromycin resistant genotypes was 2,46%, with predominance of A2143G 23S rDNA point mutation. Conclusions: The PCR/RFLP assay was a rapid and accurate H. pylori diagnostic and clarithromycin resistance determination method useful for routine practice. As prevalence of primary resistance of H. pylori to clarithromycin due to A2142G and A2143G mutations remains low in Marilia, the standard clarithromycin containing triple therapy is still valid. (AU)

• Processo FAPESP: 03/03675-7 - Detecção de cepas de Helicobacter pylori resistentes a claritromicina em biópsias gástricas de indivíduos infectados de Marília - São Paulo
• Beneficiário: Tin Hung Ho
• Linha de fomento: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 08/01394-4 - Investigação da resistência primária de Helicobacter pylori à claritromicina em amostras de biópsias gástricas de indivíduos da região de Marília-SP
• Beneficiário: Marcia Aparecida Speranca
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 05/02482-6 - Desenvolvimento de método de diagnóstico molecular para a detecção de mutações envolvidas na resistência da bactéria Helicobacter pylori a claritromicina
• Beneficiário: George Arouche da Camara Lopes
• Linha de fomento: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 08/01395-0 - Investigação da resistência primária de Helicobacter pylori à claritromicina em amostras de biópsias gástricas de indivíduos da região de Marília-SP
• Beneficiário: Rodrigo Augusto Basso Lopes
• Linha de fomento: Bolsas no Brasil - Iniciação Científica