title: Linezolid susceptibility in Helicobacter pylori, including strains with multidrug resistance.
abstract: Only a few studies have evaluated Helicobacter pylori susceptibility to linezolid. The aim of the present study was to assess linezolid susceptibility in H. pylori, including strains with double/multidrug resistance. The susceptibility of 53 H. pylori strains was evaluated by Etest and a breakpoint susceptibility testing method. Helicobacter pylori resistance rates were as follows: amoxicillin, 1.9%; metronidazole, 37.7%; clarithromycin, 17.0%; tetracycline, 1.9%; levofloxacin, 24.5%; and linezolid (>4 mg/L), 39.6%. The linezolid MIC50 value was 31.2-fold higher than that of clarithromycin and 10.5-fold higher than that of levofloxacin; however, 4 of 11 strains with double/multidrug resistance were linezolid-susceptible. The MIC range of the oxazolidinone agent was larger (0.125-64 mg/L) compared with those in the previous two reports. The linezolid resistance rate was 2.2-fold higher in metronidazole-resistant strains and in strains resistant to at least one antibiotic compared with the remaining strains. Briefly, linezolid was less active against H. pylori compared with clarithromycin and levofloxacin, and linezolid resistance was linked to resistance to metronidazole as well as to resistance to at least one antibiotic. However, linezolid activity against some strains with double/multidrug resistance may render the agent appropriate to treat some associated H. pylori infections following in vitro susceptibility testing of the strains. Clinical trials are required to confirm this suggestion.
authors.affiliation: Department of Microbiology, Medical University of Sofia, Zdrave Street 2, Sofia 1431, Bulgaria. Electronic address: l.boyanova@hotmail.com.
authors.forename: Lyudmila
authors.initials: L
authors.lastname: Boyanova
authors.affiliation: Department of Gastroenterology, University Hospital St Ekaterina, Medical University of Sofia, blvd. Pencho Slaveikov 52A, Sofia, Bulgaria.
authors.forename: Ivailo
authors.initials: I
authors.lastname: Evstatiev
authors.affiliation: Department of Microbiology, Medical University of Sofia, Zdrave Street 2, Sofia 1431, Bulgaria.
authors.forename: Galina
authors.initials: G
authors.lastname: Gergova
authors.affiliation: Gastroenterology Clinic, Department of Pediatrics, University Pediatric Hospital, blvd. Acad. Iv. Geshov 11, Sofia, Bulgaria.
authors.forename: Penka
authors.initials: P
authors.lastname: Yaneva
authors.affiliation: Department of Microbiology, Medical University of Sofia, Zdrave Street 2, Sofia 1431, Bulgaria.
authors.forename: Ivan
authors.initials: I
authors.lastname: Mitov
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017291:Clarithromycin / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000502:physiology*; D016481:Helicobacter Infections / Q000188:drug therapy; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D064704:Levofloxacin / Q000494:pharmacology; D000069349:Linezolid / Q000494:pharmacology*; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D064704:Levofloxacin; D000658:Amoxicillin; D013752:Tetracycline; D017291:Clarithromycin; D000069349:Linezolid
keywords: Antibiotic; Helicobacter pylori; Linezolid; Multidrug; Resistance