Microbiology Discovery ISSN 2052-6180 Special Section | Microbial Pathogenesis | Original Open Access Growth of the Desulfomicrobium sp. strains, their sulfate- and lactate usage, production of sulide and acetate by the strains isolated from the human large intestine Ivan V. Kushkevych Abstract he aim and background of the study were to investigate bacterial growth of the Desulfomicrobium sp. strains from human large intestine, and to study the processes usage of sulfate- and lactate, production of sulide and acetate by the obtained bacteria as well as to carry out cluster and correlation analysis of these processes. Microbiology methods of the study for bacterial strains cultivation and photometric methods for determination of bacterial biomass and hydrogen sulide concentration were used, sulfate ions concentration was determined by turbidymetric method, lactate concentration was carried out by lactate dehydrogenase. Acetate ions accumulation by the strains was determined by titration. Using the experimental data, the methods of statistical analysis have been also used. he highest biomass (3.34 g/l) has been accumulated by the Desulfomicrobium sp. strain Rod-9 on the sixth day of cultivation, in comparison to the other strains. Studied strains of the Desulfomicrobium sp. actively reduced the sulfate ions and produced hydrogen sulide. he highest concentration of hydrogen sulide (3.14 mM) was produced by the SRB Rod-9 strain on the eighth day of cultivation; while, the strain used about 98% of the sulfate compared with its initial concentration. he strains used lactate fully on the sixth day of cultivation and produced acetate. Clustering of the parameters of the bacterial growth, the sulfate and lactate usage as well as hydrogen sulide and acetate production by the various Desulfomicrobium sp. strains has been carried out. he correlation coeicients between the parameters have been determined. Keywords: Sulfate-reducing bacteria, Desulfomicrobium, intestinal microbiocenosis, sulfates, sulide, inlammatory bowel diseases © 2014 Ivan V. Kushkevych; licensee Herbert Publications Ltd. his is an Open Access article distributed under the terms of Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0). his permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction The Desulfomicrobium genus belongs to sulfate-reducing bacteria (SRB) [3]. The species of the genus is the short, straight rod-or ellipsoidal-shaped cells, with rounded ends, either singularly or in pairs. Their size is 0.5–0.9×1.3–2.9 μm. The bacteria reduce sulfate to hydrogen sulfide [3]. They oxidize organic compounds incompletely, with the formation of acetate as an end product [15]. The bacteria can grow using sulfate as an electron acceptor during sulfate anaerobic respiration [2]. The Desulfomicrobium bacteria use various nutrients in the human intestine. The bacteria use simple organic compounds (lactate, pyruvate, ethanol, formate and hydrogen) that act as electron donors during sulfate respiration [3,12]. In recent years, the bacteria are often isolated from the oral cavity and intestines of both humans and animals. Van der Hoeven et al., and Willis et al., isolated SRB species from human oral cavity [25,30]. The SRB were also found in subjects with good oral hygiene and subjects who refrained from oral hygiene procedures [19,20,25,29,30]. These bacteria detected on buccal mucosa, vestibulum, palate, tongue, and with a higher frequency in saliva and in plaque [19,20,30]. Therefore, SRB are commensals belonging to the normal oral microbiota. They grow developing biofilms in sites with little access of oxygen [20,22]. The acute inflammation of the intestinal mucosa, increasing its permeability, bloody diarrhea, abdominal pain, frequent need for a bowel movement, weight loss, arthritis, discomfort and general malaise often found in a lot of various people. During these diseases an increased number of SRB in the gut was often detected [5,8,16,21,23,24]. The presence of sulfate in the intestine stimulates the growth of SRB that reduce sulfate to H 2 S. Hydrogen sulfide affects the lining of the intestines, it is toxic for epithelial cells, specifically inhibits the growth colonocytes [2], phagocytosis, causes death of other intestinal bacteria, induces hyperproliferation and metabolic abnormalities of epithelial cells [16,23,24,31]. It was found that the concentration of this metabolite and the number of SRB significantly increased during inflammatory bowel processes [21,23,24]. The use of antibiotics (metronidazole or ciprofloxacin) leads to decrease the SRB number and consequently, to the formation of hydrogen sulfide. Inhibition of growth of intestinal SRB causes a decrease in hydrogen sulfide concentration in the human intestinal lumen [5,16]. In patients with ulcerative colitis, SRB were found during the peak of the disease accounting for 95% of the total quantity of intestinal microbiota and then during the recovery stage at a reduced quantity of 55% of the total micobiota [8,9,10]. A viable SRB number is three orders of magnitude larger Correspondence: ivan.kushkevych@gmail.com Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, Palackeho 1/3, CZ-61242 Brno, Czech Republic. CrossMark ← Click for updates