Esther Tamayo1, Milagrosa Montes2, María Fernández-Reyes3, Jacobo Lizasoain4, Begoña Ibarra4, Usua Mendarte4, Eva Zapata5, Josune Mendiola6, Emilio Pérez-Trallero7. 1. Biomedical Research Center Network for Respiratory Diseases (CIBERES), San Sebastián, Spain. 2. Biomedical Research Center Network for Respiratory Diseases (CIBERES), San Sebastián, Spain; Microbiology Department, Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain. Electronic address: milagrosa.montesros@osakidetza.net. 3. Microbiology Department, Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain. 4. Gastroenterology Department, CS Gros-Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain. 5. Gastroenterology Department, Hospital Mendaro, Mendaro, Gipuzkoa, Spain. 6. Microbiology Department, Hospital Mendaro, Mendaro, Gipuzkoa, Spain. 7. Biomedical Research Center Network for Respiratory Diseases (CIBERES), San Sebastián, Spain; Microbiology Department, Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain; Medicine Faculty, University of the Basque Country, UPV/EHU, San Sebastián, Spain.
Abstract
OBJECTIVES: Clarithromycin resistance (CLR-R) is the main reason for failure of Helicobacter pylori infection treatment, which is frequently empirically prescribed due to the erroneous belief that culture for susceptibility testing is difficult. The aim of this study was to determine CLR-R in a region of southern Europe and to evaluate the utility of a PCR sequencing assay applied on gastroduodenal biopsies in detecting H. pylori and clarithromycin (CLR) susceptibility. METHODS: The susceptibility of all H. pylori isolates obtained by culture during 2013-2015 was determined by Etest. During 2014-2015, H. pylori detection and CLR susceptibility were also studied by PCR followed by sequencing performed on gastroduodenal biopsies. Point mutations in the 23S rRNA gene were studied in all CLR-resistant isolates in 2014. RESULTS: Of 1986 H. pylori isolates obtained by culture (63 from children and 1923 from adults), 349 (17.6%) were CLR-resistant [21/63 (33.3%) in children and 328/1923 (17.1%) in adults; P<0.001], of which 31.5% were also resistant to levofloxacin. The main mutations detected were A2147G (79.8%), A2146G (17.2%) and A2146C (2%). Concordance between the PCR sequencing assay on biopsies and CLR susceptibility by Etest after culture was 89.8%. CONCLUSIONS: CLR-R was high in Gipuzkoa, northern Spain. The molecular PCR method performed directly on biopsies was a good alternative to the traditional Etest susceptibility method and was an aid when culture was non-viable.
OBJECTIVES:Clarithromycin resistance (CLR-R) is the main reason for failure of Helicobacter pylori infection treatment, which is frequently empirically prescribed due to the erroneous belief that culture for susceptibility testing is difficult. The aim of this study was to determine CLR-R in a region of southern Europe and to evaluate the utility of a PCR sequencing assay applied on gastroduodenal biopsies in detecting H. pylori and clarithromycin (CLR) susceptibility. METHODS: The susceptibility of all H. pylori isolates obtained by culture during 2013-2015 was determined by Etest. During 2014-2015, H. pylori detection and CLR susceptibility were also studied by PCR followed by sequencing performed on gastroduodenal biopsies. Point mutations in the 23S rRNA gene were studied in all CLR-resistant isolates in 2014. RESULTS: Of 1986 H. pylori isolates obtained by culture (63 from children and 1923 from adults), 349 (17.6%) were CLR-resistant [21/63 (33.3%) in children and 328/1923 (17.1%) in adults; P<0.001], of which 31.5% were also resistant to levofloxacin. The main mutations detected were A2147G (79.8%), A2146G (17.2%) and A2146C (2%). Concordance between the PCR sequencing assay on biopsies and CLR susceptibility by Etest after culture was 89.8%. CONCLUSIONS:CLR-R was high in Gipuzkoa, northern Spain. The molecular PCR method performed directly on biopsies was a good alternative to the traditional Etest susceptibility method and was an aid when culture was non-viable.