Clarithromycin resistance in Helicobacter pylori and its molecular determinants in Northern Spain, 2013-2015.
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.



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.



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%.



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.
Biomedical Research Center Network for Respiratory Diseases (CIBERES), San Sebastián, Spain.
Esther
E
Tamayo
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.
Milagrosa
M
Montes
Microbiology Department, Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain.
María
M
Fernández-Reyes
Gastroenterology Department, CS Gros-Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain.
Jacobo
J
Lizasoain
Gastroenterology Department, CS Gros-Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain.
Begoña
B
Ibarra
Gastroenterology Department, CS Gros-Hospital Universitario Donostia-Instituto Biodonostia, San Sebastián, Spain.
Usua
U
Mendarte
Gastroenterology Department, Hospital Mendaro, Mendaro, Gipuzkoa, Spain.
Eva
E
Zapata
Microbiology Department, Hospital Mendaro, Mendaro, Gipuzkoa, Spain.
Josune
J
Mendiola
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.
Emilio
E
Pérez-Trallero
D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D017291:Clarithromycin / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial; D005753:Gastric Mucosa / Q000382:microbiology; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007413:Intestinal Mucosa / Q000382:microbiology; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013030:Spain; D055815:Young Adult
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012338:RNA, Ribosomal, 23S; D017291:Clarithromycin
23S rRNA; Clarithromycin; Gastroduodenal biopsy; Helicobacter pylori; Mutation; Susceptibility-guided treatment