en Host-pathogen interactions and susceptibility factors Host-pathogen interactions and susceptibility factors Review article Review article <div style="text-align: justify;"><span style="font-size:12pt"><span new="" roman="" style="font-family:" times=""><strong><span style="font-size:10.0pt"><span style="color:black">Introduction:<i> Helicobacter pylori</i> (<i>H. pylori</i>) </span></span></strong><span style="font-size:10.0pt"><span style="color:black">infection is one of the most common chronic bacterial infections of the gastric mucosa. Its prevalence is estimated in approximately half of the world&rsquo;s population and varies between 30% and 90% depending on geographic and socioeconomic factors. It is strongly associated with chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric malignancy. This narrative review aims to<b> </b>provide an updated overview of <i>H. pylori</i> infection, including its epidemiology, growth characteristics, transmission routes, risk factors, diagnostic approaches, and current treatment strategies. <b>Methods:</b> This narrative review synthesizes evidence retrieved from PubMed, Scopus, and Web of Science databases for articles published between 2000 and 2025. <b>Results:</b> Global prevalence of <i>H. pylori</i> infection varies considerably across regions, ranging from approximately 30% to 90%, with higher rates reported in developing countries. Transmission occurs predominantly via oral&ndash;oral, fecal&ndash;oral, and intrafamilial routes. Major risk factors include childhood exposure, overcrowded living conditions, poor sanitation, and low socioeconomic status. Current diagnostic techniques are broadly classified into invasive and non-invasive methods. Invasive techniques include culture, molecular assays, histology, and the rapid urease test (RUT), whereas non-invasive methods include the urea breath test (UBT), stool antigen testing (SAT), and serology. The UBT and SAT are currently among the most accurate non-invasive tools for detecting active infection. Current guidelines recommend proton pump inhibitor (PPI) or potassium-competitive acid blocker (PCAB)-based regimens combined with antibiotics, with bismuth-containing quadruple therapy preferred in regions with high or unknown clarithromycin resistance. Rising antimicrobial resistance, particularly to clarithromycin, metronidazole, and fluoroquinolones, continues to compromise eradication success and highlights the need for susceptibility-guided therapy where available. <b>Conclusion:</b> Despite advances in the understanding and management of <i>H. pylori</i> infection, its high global prevalence and the growing emergence of antimicrobial resistance remain major challenges. Continued efforts are needed to develop region-specific treatment strategies, effective preventive measures, and novel vaccines and therapeutic approaches.</span></span></span></span></div> <br> &nbsp; Helicobacter pylori, Helicobacter infections, Epidemiology, Antimicrobial resistance, Quadruple therapy 0 0 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-720-1&slc_lang=en&sid=1 Zulqarnain No Institute of Molecular Biology and Biotechnology, University of Lahore, Pakistan Haleema Sadia No Department of Epidemiology and Public Health, University of Agriculture Faisalabad, Pakistan Muhammad Adil madilnawaz143@gmail.com 0009-0008-0926-4455 Yes Department of Clinical Medicine and Surgery, University of Agriculture Faisalabad, Pakistan Mirwaise Khan No State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China Anum Urooj No National Institute of Food Science and Technology, University of Agriculture, Faisalabad, Pakistan Talha Najam No Department of Animal Nutrition, University of Agriculture, Faisalabad, Pakistan