*Article* **Hydrogen Sulfide as a Toxic Product in the Small–Large Intestine Axis and its Role in IBD Development**

#### **Ivan Kushkevych 1,\*, Dani Dordevi´c 2, Peter Kollar 3, Monika Vít ˇezová 1 and Lorenzo Drago 4**


Received: 2 July 2019; Accepted: 17 July 2019; Published: 19 July 2019

**Abstract:** The small–large intestine axis in hydrogen sulfide accumulation and testing of sulfate and lactate in the gut–gut axis of the intestinal environment has not been well described. Sulfate reducing bacteria (SRB) of the *Desulfovibrio* genus reduce sulfate to hydrogen sulfide and can be involved in ulcerative colitis development. The background of the research was to find correlations between hydrogen sulfide production under the e ffect of an electron acceptor (sulfate) and donor (lactate) at di fferent concentrations and *Desulfovibrio piger* Vib-7 growth, as well as their dissimilatory sulfate reduction in the intestinal small–large intestinal environment. Methods: Microbiological, biochemical, and biophysical methods, and statistical processing of the results (principal component and cross-correlation analyses) were used. Results: *D. piger* Vib-7 showed increased intensity of bacterial growth and hydrogen sulfide production under the following concentrations of sulfate and lactate: 17.4 mM and 35.6 mM, respectively. The study showed in what kind of intestinal environment *D. piger* Vib-7 grows at the highest level and produces the highest amount of hydrogen sulfide. Conclusions: The optimum intestinal environment of *D. piger* Vib-7 can serve as a good indicator of the occurrence of inflammatory bowel diseases; meaning that these findings can be broadly used in medicine practice dealing with the monitoring and diagnosis of intestinal ailments.

**Keywords:** small–large intestine axis; hydrogen sulfide; *Desulfovibrio*; bowel disease; colitis
