Investigation for the presence of Helicobacter pylori within Candida spp. in the stomach

Project no. 23381 · Status: Kapanmış (Yayın bekleniyor) · 2021

Summary

Studies conducted in recent years show that Helicobacter pylori protects itself by hiding in the vacuole of the Candida yeast. This strategy is thought to be a “survival strategy” in which the bacterium develops itself against changes in environmental pH or antibiotic treatments used to destroy it. Intracellular endofungal bacteria live inside the vacuoles of yeasts, protect their cell structure, continue to survive and transmit themselves to future generations. Candida spp. serves as an alternative host that is extremely resistant to stressful conditions and will protect the bacteria it contains against these conditions.           In this thesis study, stomach biopsy samples of 233 patients who applied to the Gastroenterology clinic of Ege University Faculty of Medicine due to various complaints and who were medically indicated for esophagogastroduodenoscopy (EGD-Upper GIS Endoscopy) procedure were used. Candida species were isolated from biopsy samples taken from the antrum and corpus regions of the stomach. Fluorescence in situ hybridization method (FISH), one of the most commonly used methods in culture-independent molecular analysis of bacterial species, was used to detect endofungal H. pylori in the vacuole of Candida species. Using the total DNA of Candida species in which endofungal H. pylori was detected, amplification of the H. pylori 16S rDNA gene region and the virulence genes of H. pylori, namely ureAB, vacA gene s1/s2 allele and vacA gene m1/m2 allele, was performed. In vitro antifungal susceptibility tests of Candida species harboring endofungal H. pylori against amphotericin B and fluconazole were performed.           As a result of the study, a total of 159 Candida species were isolated from the stomach biopsy samples of 94 (40,3 %) of the 233 patients analyzed. The number of Candida spp isolates isolated from the antrum region of the stomach is 92 and the number of Candida spp isolates isolated from the corpus region is 67. As a result of FISH analysis performed with the EUB338 probe of 159 Candida isolates, intracellular endofungal bacteria were detected in 99 of them. As a result of FISH analysis performed with an H. pylori specific probe, endofungal H. pylori was detected in 48 Candida spp isolates. H. pylori was not detected in 51 Candida isolates in which intracellular endofungal bacteria were detected. As a result of FISH analysis, the 16S rDNA gene specific to H. pylori was detected in all 48 Candida spp. isolates in which the presence of endofungal H. pylori was detected. The s1/s2 allele of the vacA gene, one of the virulence genes of H. pylori, was detected in 8 Candida spp. isolates harboring endofungal H. pylori. The m1/m2 allele of the vacA gene was not detected in any isolate. The ureAB gene, one of the virulence genes of H. pylori, was detected in 7 Candida spp isolates in which endofungal H. pylori was detected. In the study, the isolates coded 2A, 4K, 23A, 24K, 33A, 37A, 41A, 74K, 114K2, 115A, 116K, 126K, 127A, 136K, 165A, 199A, 204K, 239A, 250K, 257A, 263A, 368K2, 369A3, 370K2, 406K , in which the presence of H. pylori was detected, were confirmed to be Candida albicans by C. albicans species-specific PCR. As a result of the sequence analysis of the remaining isolates, the isolate coded 2A, 2A, 4K, 23A, 24K, 33A, 34K, 37A, 38K, 41A, 74K, 114K1, 114K2, 115A, 116K, 126K, 127A, 129A, 136K, 165A, 166K, 199A, 204K, 214K, 239A, 246K, 250K, 257A, 263A, 305A, 368K2, 369A3, 370K2, 400K, 406K among the Candida species containing endofungal H. pylori were detected as Candida albicans species; isolate coded 119A was detected Nakaseomyces glabratus (Candida glabrata); isolate coded 260K was detected as Candida tropicalis species. In the study, antifungal susceptibility testing of 48 Candida spp. isolates against amphotericin B and fluconazole was performed. The MIC50 value of amphotericin B at 24 hours for all isolates was found to be 64 µg/ml. The MIC50 value of fluconazole at the 24th hour for C. albicans isolates was 24 µg/ml, and the MIC50 value at the 24th hour for C. tropicalis isolates was 16 µg/ml. The amphotericin B and fluconazole MIC values of the C. glabrata isolate were found to be 64 µg/ml.           Data on the presence of H. pylori among Candida species isolated from stomach biopsy samples of patients and the data on the histopathological examination of stomach biopsy samples of the same patients for the presence of H. pylori are not statistically significant (p>0.05). The results of histopathological examination of biopsy samples taken from the antrum region of the stomach of individuals for the presence of H. pylori and whether or not they had previously received H. pylori eradication treatment are statistically significant (p<0.05). The results of histopathological examination of the individuals' smoking habit and the gastric biopsy samples taken from the corpus for the presence of H. pylori are statistically significant (p<0.05).               The results of our study point out that in addition to fighting bacteria in order to prevent the recurrence of H. pylori-related diseases, fighting the yeast that contains bacteria is also important in terms of recurrence of the disease. It should be taken into consideration that the release of the bacterium from the yeast under unknown conditions in the stomach environment may cause individuals to become re-infected with H. pylori. Recurrent H. pylori infections negatively affect the patient's quality of life and may cause morbidity and mortality due to pathologies such as stomach ulcer, bulbus ulcer, and stomach cancer. In light of all this information, the results of our study are clinically important. We also believe that our study will shed light on future studies on the diversity of endofungal bacteria living in yeast. The mechanisms of     H. pylori entry and exit into the yeast cell are still unclear and further research is needed on this subject. Our study is the first study to investigate the presence of endofungal H. pylori in Candida in Turkey.

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