historically, it was believed that the stomach is an unfavourable environment for bacteria due to the its acidic conditions and presence difference antimicrobial factors, but after isolating and identifying Helicobacter pylori from gastric biopsies, researchers found that additional gastric microbial species, beyond Helicobacter pylori are present in gastric environment which can play a role in the stomach health and disease. In the present study, culture-base method and 16S rRNA gene sequencing were used to evaluate the distribution of aerobic and anaerobic bacteria in gastric biopsies of dyspeptic patients with gastritis and gastric atrophy.
In this study, 10 gastric biopsy samples obtained from patients referred to the Masoud Gastroenterology and Liver Clinic (5 gastritis patients and 5 gastric atrophy patients) were recruited . First, enrichment and inoculation were done on different selective and non-selective media and incubation in different temperature and oxygen conditions. Then the bacteria were isolated and purified. In the next step, the DNA of the isolated bacteria was extracted and PCR was performed using prokaryotic-specific 16S rRNA gene .The amplified fragments were sequenced and compared with the published sequences in the gene bank.
At least one distinct bacterium was isolated from each biopsy. Totally, 28 bacterial colonies were isolated from 10 examined biopsies . The most prominent bacteria were Bacillus, Streptococcus, Staphylococcus and Lactobacillus, which were found in both types of biopsy samples. However, Brevundimonas sp. and Ligilactobacillus sp. were only cultured from biopsies of atrophy patients and Rothia sp. and Achromobacter sp. were isolated only from people with gastritis. Furthermore, overall 10 lactic acid bacteria were isolated and 7/10 were related to patients with gastric atrophy.
In this study, common and different bacteria were isolated and identified from the biopsy of gastritis and gastric atrophy patients. More extensive studies are needed to cultivate and identify stomach bacteria in different stages of the disease with greater specificity.
