title: Antibiotic resistance and cagA gene correlation: a looming crisis of Helicobacter pylori.
abstract: OBJECTIVE
  To determine antibiotic resistance of Helicobacter pylori (H. pylori) in Pakistan and its correlation with host and pathogen associated factors.
  
  
  METHODS
  A total of 178 strains of H. pylori were isolated from gastric biopsies of dyspeptic patients. Susceptibility patterns against first and second-line antibiotics were determined and trends of resistance were analyzed in relation to the sampling period, gastric conditions and cagA gene carriage. The effect of cagA gene on the acquisition of resistance was investigated by mutant selection assay.
  
  
  RESULTS
  The observations showed that monoresistant strains were prevalent with rates of 89% for metronidazole, 36% for clarithromycin, 37% for amoxicillin, 18.5% for ofloxacin and 12% for tetracycline. Furthermore, clarithromycin resistance was on the rise from 2005 to 2008 (32% vs 38%, P = 0.004) and it is significantly observed in non ulcerative dyspeptic patients compared to gastritis, gastric ulcer and duodenal ulcer cases (53% vs 20%, 18% and 19%, P = 0.000). On the contrary, metronidazole and ofloxacin resistance were more common in gastritis and gastric ulcer cases. Distribution analysis and frequencies of resistant mutants in vitro correlated with the absence of cagA gene with metronidazole and ofloxacin resistance.
  
  
  CONCLUSIONS
  The study confirms the alarming levels of antibiotic resistance associated with the degree of gastric inflammation and cagA gene carriage in H. pylori strains.
authors.affiliation: Immunology and Infectious Diseases Research Laboratory, Department of Microbiology, University of Karachi, University Road, Karachi 75270, Pakistan. adnankh@uok.edu.pk
authors.forename: Adnan
authors.initials: A
authors.lastname: Khan
authors.forename: Amber
authors.initials: A
authors.lastname: Farooqui
authors.forename: Hamid
authors.initials: H
authors.lastname: Manzoor
authors.forename: Syed Shakeel
authors.initials: SS
authors.lastname: Akhtar
authors.forename: Muhammad Saeed
authors.initials: MS
authors.lastname: Quraishy
authors.forename: Shahana Urooj
authors.initials: SU
authors.lastname: Kazmi
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001706:Biopsy; D016009:Chi-Square Distribution; D004252:DNA Mutational Analysis; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics*; D006801:Humans; D016014:Linear Models; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010154:Pakistan / Q000453:epidemiology; D013270:Stomach / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori