Determinação molecular de resistência genotípica primária do Helicobacter pylori à claritromicina e fluoroquinolonas em amostras gástricas obtidas por endoscopia digestiva alta no Brasil

Autor: Bruno Squarcio Fernandes Sanches
Přispěvatelé: Luiz Gonzaga Vaz Coelho, Eduardo Garcia Vilela, Maria do Carmo Friche Passos, Antônio Frederico Novaes Magalhães, Lucia Libanez Bessa Campelo Braga
Jazyk: portugalština
Rok vydání: 2016
Předmět:
Zdroj: Repositório Institucional da UFMG
Universidade Federal de Minas Gerais (UFMG)
instacron:UFMG
Popis: INTRODUCAO: Alem da aderencia incompleta ao tratamento, o principal fator associado a falha terapeutica no tratamento de Helicobacter pylori (HP) e a resistencia bacteriana aos antimicrobianos, adquirida principalmente por mutações geneticas. A deteccao da prevalencia dessas mutacoes e fundamental para o conhecimento das taxas de resistencia bacteriana e adequacao dos esquemas terapeuticos. OBJETIVO: Estimar a prevalencia da resistencia primaria de HP a claritromicina e as fluorquinolonas atraves de um teste molecular em amostras de conveniencia coletadas nas cinco regioes do Brasil. METODOS: Foram selecionados, em seis centros de endoscopia do pais, 519 pacientes com teste sorologico rapido positivo para HP (65,7% mulheres, idade media 43 [variacao 19-79] anos), nao tratados previamente para essa infeccao. Todos os pacientes se submeteram a endoscopia digestiva com biopsias de antro e corpo e realizacao doteste molecular GenoType HelicoDR (Hain Life Science, Alemanha) para a deteccao do HP e das mutacoes pontuais dos genes responsaveis pela resistencia a claritromicina e fluorquinolonas. O procedimento molecular constituia-se de tres etapas: extracao do DNA a partir das amostras endoscopicas, amplificacao multiplex e hibridizacao reversa. As mutacoes mais frequentemente associadas a resistenciaaos dois antibioticos foram avaliadas. RESULTADOS: Vinte e nove pacientes foram excluidos por ausencia da infeccao por HP ao teste molecular (21 casos) e ausencia de banda gyrA (08 casos). No total, a resistencia a claritromicina foi detectada em 83 amostras (16,9%) e as fluorquinolonas em 66 amostras (13,5%). Nas regioes estudadas, a resistencia a claritromicina e as fluorquinolonas foi, respectivamente,de 16,6% e 2,7% na regiao Norte (Manaus), 14,5% e 13,7% na regiao Nordeste (Salvador e Maceio), 19,2% e 15,4% na regiao Centro-Oeste (Goiania), 17,5% e 13,8% na regiao Sudeste (Belo Horizonte) e 19,1% e 16,4% na regiao Sul (Porto Alegre). A mutacao pontual A2147G foi a mais comum (90,3%) entre as cepas resistentes a claritromicina. No grupo resistente as fluorquinolonas, as mutacoes nao especificadas pelo metodo foram as mais frequentes (37.9%), seguidas da mutacaoD91N (34,9%). Heterogeneidade genotipica foi observada em 25,3% das amostras. A resistencia dupla a claritromicina e fluorquinolonas foi encontrada em 4,3% dos casos (n=21). CONCLUSOES: No Brasil, a resistencia genotipica primaria de HP a 10 claritromicina situa-se, em media, entre 15 a 20%, em faixa limitrofe para o uso empirico das terapias triplas contendo claritromicina. A resistencia primaria asfluoroquinolonas tambem se apresenta em niveis preocupantes. O teste molecular constitui uma ferramenta diagnostica adequada e exequivel para a determinacao e monitoramento da resistencia genotipica primaria de HP aos antibioticos. INTRODUCTION: In addition to the incomplete adherence to treatment, the main factor associated with therapeutic failure in the treatment of Helicobacter pylori (HP) is bacterial resistance to antimicrobials, mainly acquired by genetic mutations. The detection of the prevalence of these mutations is critical to the understanding of bacterial resistance rates and adequacy of treatment regimens. OBJECTIVE: To estimate the prevalence of HP's primary resistance to clarithromycin andfluoroquinolones through a molecular test on convenience samples collected in five regions of Brazil. METHODS: We selected six endoscopy centers in the country, 519 patients with positive rapid serologic test for HP (65.7% women, mean age 43 [range 19-79] years), not previously treated for this infection. All patients underwent endoscopy with biopsies of antrum and body and realization of molecular test GenoType HelicoDR (Hain Life Science, Germany) for the detection of HP and pointmutations of the genes responsible for resistance to clarithromycin andfluoroquinolones. The molecular procedure constituted of three steps: DNA extraction from endoscopic samples, multiplex amplification and reverse hybridization. Mutations more often associated with resistance to both antibiotics were evaluated. RESULTS: Twenty-nine patients were excluded for lack of infection by HP to molecular testing (21 cases) and no gyrA band (08 cases). In total, the resistance to clarithromycin was detected in 83 samples (16.9%) and fluoroquinolones in 66 samples (13.4%). In the regions studied, resistance to clarithromycin andfluoroquinolones was respectively 16.6% and 2.7% in the North (Manaus), 14.5% and 13.7% in the Northeast (Salvador and Maceio) 19.2% and 15.4% in the Midwest region (Goiania), 17.5% and 13.8% in the Southeast (Belo Horizonte) and 19.1% and 16.4% in the South (Porto Alegre). The point mutation A2147G was the most common (90.3%) among strains resistant to clarithromycin. In resistant to fluoroquinolones group, the mutations not specified by the method were the mostcommon (37.8%), followed by the D91N mutation (34.8%). Genotypic heterogeneity was observed in 25.3% of samples. The double resistance to clarithromycin and fluoroquinolones was found in 4.3% of cases (n = 21). CONCLUSION: In Brazil, primary genotypic resistance to clarithromycin HP is situated in the borderland (15 to 20%) where clarithromycin-containing triple therapies are suggested to be empirically12 used. The primary resistance to fluoroquinolones also shows growing and worrying levels. Molecular testing is an appropriate and feasible diagnostic tool for the determination and monitoring of primary genotypic resistance of HP to antibiotics.
Databáze: OpenAIRE
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