en Gastroentrology Gastroentrology Original Article Original Article <p style="text-align:justify"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> Despite growing knowledge in microbiome studies data about the diversity of cultivable bacteria and their drug resistance patterns in patients with gastritis are scant. </span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Methods:</span></i></b> Two<b> </b>gastric biopsies of 171 symptomatic patients were collected and examined by histological and microbiological methods. Viable bacteria were characterized using conventional techniques, and antimicrobial susceptibility of the isolates was detected. </span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Results:</span></i></b> Acute gastritis, chronic gastritis, and peptic ulcers were detected in 3.5%, 86.5%, and 5.8% of the patients, respectively. Culturable bacteria were isolated from 71.3% of the patients, including <i>Helicobacter pylori</i> (<i>H. pylori)</i> (26.9%), <i>Staphylococcus epidermidis</i> (19.8%), <i>Micrococcus</i> (1.1%), <i>Streptococcus viridans</i> (<i>S. viridans</i>) (13.4%), <i>Enterococcus faecalis</i> (<i>E. faecalis</i>) (4.6%), <i>Staphylococcus aureus</i> (<i>S. aureus</i>) (1.7%), and Group D <i>Streptococcus</i> (7.1%). Single infection and coexistence of two and three types of bacteria were detected in 43.2%, 15.2%, and 5.2% of the patients, respectively. An odd ratio of 4.4 was measured for <i>Staphylococcus </i>spp. in patients with acute gastritis (<i>P-value </i>= 0.08). <i>E</i>-test<i> </i>results showed intermediate resistance to penicillin in 66.6% of the <i>S. aureus</i> isolates, while resistance to vancomycin was detected only in the <i>S. viridans</i> (30.4%). Resistance to linezolid was detected in 100%, 17.4%, and 16.7% of <i>E. faecalis</i>, <i>S. viridans</i>, and group D <i>Streptococci</i> isolates, respectively. A high frequency of resistance to penicillin, clindamycin, linezolid, erythromycin, and tetracycline was detected in <i>S. epidermidis</i> strains. </span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> Our results highlighted the importance of Gram-positive bacteria in the etiology of gastritis. Resistance of these bacteria to different classes of antibiotics should be considered in the clinical setting. <span lang="FA" dir="RTL" style="font-size:10.0pt"></span></span></span></span><br> &nbsp;</p> Gastritis, Bacterial infections, Antibiotic resistance, Non-Helicobacter bacteria 143 151 http://caspjim.com/browse.php?a_code=A-10-3647-1&slc_lang=en&sid=1 Masoud Alebouyeh masoud.alebouyeh@gmail.com 100319475328460055898 100319475328460055898 Yes Pediatric Infections Research Centre, Research Institute for Children’s Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran Malihe Aminzadeh athena.mirbagheri@yaho.com 100319475328460055899 0009-0009-1933-7539 No Department of Biology, Faculty of Basic Science, Shahed University, Tehran, Iran Masoumeh Bahiraee naxi.bahiraee@gmail.com 100319475328460055900 100319475328460055900 No Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Seyedeh Zohre Mirbagheri z_mirbagheri@hotmail.com 100319475328460055901 0009-0009-6494-9678 No Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, I.R. Iran Ronak Bakhtiari rounakbakhtiari@yahoo.com 100319475328460055902 100319475328460055902 No Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran