Brief Article
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World J Gastroenterol. May 14, 2012; 18(18): 2245-2252
Published online May 14, 2012. doi: 10.3748/wjg.v18.i18.2245
Antibiotic resistance and cagA gene correlation: A looming crisis of Helicobacter pylori
Adnan Khan, Amber Farooqui, Hamid Manzoor, Syed Shakeel Akhtar, Muhammad Saeed Quraishy, Shahana Urooj Kazmi
Adnan Khan, Amber Farooqui, Shahana Urooj Kazmi, Immunology and Infectious Diseases Research Laboratory, Department of Microbiology, University of Karachi, University Road, Karachi 75270, Pakistan
Amber Farooqui, Division of Immunology, International Institute of Infection and Immunity, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong 515041, China
Hamid Manzoor, Syed Shakeel Akhtar, Muhammad Saeed Quraishy, Department of Surgery, Civil Hospital, Karachi 74200, Pakistan
Hamid Manzoor, Syed Shakeel Akhtar, Muhammad Saeed Quraishy, Department of Medicine, Civil Hospital, Karachi 74200, Pakistan
Author contributions: Khan A preformed the experiments and wrote the manuscript; Farooqui A contributed in experimental design and analyzed the data; Manzoor H, Akhtar SS performed clinical sampling; Quraishy MS supervised the clinical part of the study and provided samples; Kazmi SU supervised the study and revised the manuscript.
Supported by The grants of Higher Education Commission of Pakistan and University of Karachi awarded to Adnan Khan
Correspondence to: Adnan Khan, PhD, Assistant Professor, Immunology and Infectious Diseases Research Laboratory, Department of Microbiology, University of Karachi, University Road, Karachi 75270, Pakistan. adnankh@uok.edu.pk
Telephone: +92-21-99261389 Fax: +92-21-99261342
Received: August 8, 2011
Revised: December 6, 2011
Accepted: March 10, 2012
Published online: May 14, 2012
Abstract

AIM: 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.

CONCLUSION: The study confirms the alarming levels of antibiotic resistance associated with the degree of gastric inflammation and cagA gene carriage in H. pylori strains.

Keywords: Helicobacter pylori; Antibiotic resistance; cagA; Pakistan; Clarithromycin; Metronidazole; Fluoroquinolones