title: Three unsuccessful treatments of Helicobacter pylori infection by a highly virulent strain with quadruple antibiotic resistance.
abstract: We report a case of an adult patient undergoing three unsuccessful Helicobacter pylori treatments, including proton pump inhibitor (PPI), bismuth subcitrate, metronidazole and tetracycline in 2012, PPI, amoxicillin and clarithromycin in 2013, and PPI, amoxicillin and rifampin in 2014. Following the first treatment, the isolate was metronidazole and ciprofloxacin/levofloxacin resistant. After the second treatment, the isolate was resistant to metronidazole, ciprofloxacin/levofloxacin and rifampin, developing secondary clarithromycin resistance by A2143G mutation and was susceptible only to tetracycline. After the third treatment, the patient still remained H. pylori positive. Patient's strain was highly virulent (cagA (+) , cagE (+) and vacA s1a/m1/i1). The evolution of the patient's disease was from gastroesophageal reflux disease in 2012 to two duodenal ulcers in 2015. Briefly, the infecting strain showed quadruple antibiotic resistance and a transient amoxicillin resistance. Triple clarithromycin-based treatment induced secondary clarithromycin resistance by A2143G mutation, while rifampin resistance caused the third treatment failure. Several options for the next treatment regimens are discussed.
authors.affiliation: Department of Medical Microbiology, Medical University of Sofia, Zdrave Street 2, 1431, Sofia, Bulgaria. 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, Sofia, Bulgaria.
authors.forename: Ivailo
authors.initials: I
authors.lastname: Evstatiev
authors.affiliation: Department of Medical Microbiology, Medical University of Sofia, Zdrave Street 2, 1431, Sofia, Bulgaria.
authors.forename: Daniel
authors.initials: D
authors.lastname: Yordanov
authors.affiliation: Department of Medical Microbiology, Medical University of Sofia, Zdrave Street 2, 1431, Sofia, Bulgaria.
authors.forename: Rumyana
authors.initials: R
authors.lastname: Markovska
authors.affiliation: Department of Medical Microbiology, Medical University of Sofia, Zdrave Street 2, 1431, Sofia, Bulgaria.
authors.forename: Ivan
authors.initials: I
authors.lastname: Mitov
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D003131:Combined Modality Therapy / Q000379:methods; D024901:Drug Resistance, Multiple, Bacterial; D004358:Drug Therapy / Q000379:methods; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D017211:Treatment Failure; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors