In Vitro Incorporation of Helicobacter pylori into Candida albicans Caused by Acidic pH Stress

Yeasts can adapt to a wide range of pH fluctuations (2 to 10), whileHelicobacter pylori, a facultative intracellular bacterium, can adapt to a range from pH 6 to 8. This work analyzed if H. pylori J99 can protect itself from acidic pH by entering intoCandida albicansATCC 90028. Growth curves were determined forH. pyloriandC. albicansat pH 3, 4, and 7. Both microorganisms were co-incubated at the same pH values, and the presence of intra-yeast bacteria was evaluated. Intra-yeast bacteria-like bodies were detected using wet mounting, and intra-yeast binding of anti-H. pylori antibodies was detected using immunofluorescence. The presence of theH. pylorir DNA 16S gene in total DNA from yeasts was demonstrated after PCR amplification.H. pylori showed larger death percentages at pH 3 and 4 than at pH 7. On the contrary, the viability of the yeast was not affected by any of the pHs evaluated.H. pylori entered into C. albicans at all the pH values assayed but to a greater extent at unfavorable pH values (pH 3 or 4,p =0.014 and p =0.001, respectively). In conclusion, it is possible to suggest thatH. pylorican shelter itself within C. albicans under unfavorable pH conditions.