title: The Changing Profile of Helicobacter pylori Antibiotic Resistance in Singapore: A 15-Year Study.
abstract: BACKGROUND
  Antibiotic resistance is an important cause of H. pylori treatment failure. This study aimed to examine the change in H. pylori antibiotic resistance profile in Singapore over the course of 15 years.
  
  
  METHODS
  The study period was from 2000 to 2014. Gastric mucosal biopsies obtained from H. pylori-positive patients were cultured. Antibiotic susceptibility to metronidazole, clarithromycin, levofloxacin, tetracycline, and amoxicillin was tested. The change in resistance rates over time was analyzed.
  
  
  RESULTS
  A total of 708 H. pylori isolates were cultured. There was a significant increase in resistance rates for metronidazole (2000-2002: 24.8%; 2012-2014: 48.2%; p < .001), clarithromycin (2000-2002: 7.9%; 2012-2014: 17.1%; p = .022), and levofloxacin (2000-2002: 5%; 2012-2014: 14.7%; p = .007). The resistance rates for tetracycline (2000-2002: 5%; 2012-2014: 7.6%) and amoxicillin (2000-2002: 3%; 2012-2014: 4.4%) remained stable. Increase in dual (2000-2002: 6.9%; 2012-2014: 9.4%; p = .479) and triple antibiotic resistance rates (2000-2002: 0; 2012-2014: 7.6%; p < .001) were observed. Overall, the most common dual and triple resistance patterns were metronidazole/clarithromycin (4.4%) and metronidazole/clarithromycin/levofloxacin (1.8%), respectively.
  
  
  CONCLUSIONS
  Over 15 years, H. pylori resistance rates to metronidazole, clarithromycin and levofloxacin had increased. There was increased resistance to multiple antibiotics.
authors.affiliation: Department of Gastroenterology and Hepatology, Changi General Hospital, Singapore, Singapore.
authors.forename: Tiing Leong
authors.initials: TL
authors.lastname: Ang
authors.affiliation: Department of Gastroenterology and Hepatology, Changi General Hospital, Singapore, Singapore.
authors.forename: Kwong Ming
authors.initials: KM
authors.lastname: Fock
authors.affiliation: Department of Gastroenterology and Hepatology, Changi General Hospital, Singapore, Singapore.
authors.forename: Daphne
authors.initials: D
authors.lastname: Ang
authors.affiliation: Department of Gastroenterology and Hepatology, Changi General Hospital, Singapore, Singapore.
authors.forename: Andrew Boon Eu
authors.initials: AB
authors.lastname: Kwek
authors.affiliation: Department of Gastroenterology and Hepatology, Changi General Hospital, Singapore, Singapore.
authors.forename: Eng Kiong
authors.initials: EK
authors.lastname: Teo
authors.affiliation: Department of Gastroenterology and Hepatology, Changi General Hospital, Singapore, Singapore.
authors.forename: Subbiah
authors.initials: S
authors.lastname: Dhamodaran
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001706:Biopsy; D024881:Drug Resistance, Bacterial; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012846:Singapore / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antimicrobial resistance; amoxicillin; clarithromycin; levofloxacin; metronidazole; tetracycline