EFFECT OF Mg, Zn, Ca, AND Fe SUPPLEMENTS ON GROWTH, PROBIOTIC POTENTIAL, AND BIOFILM-FORMING CAPACITY OF LACTOBACILLUS BACTERIA

Abstract

The gut microbiome is a complete set of microorganisms found in the gastrointestinal (GI) tract. Lactobacillus spp. are beneficial bacteria that are normally found in the gut. They are used as a type of probiotic in order to create a homeostasis in the human microflora. One of the challenges for these bacteria is the ability to adapt to different environments in order to survive and function properly. The main research question of this study was to see whether specific dietary supplements (calcium citrate, iron(II)fumarate, zinc, magnesium oxide) change bacterial properties of Lactobacillus reuteri (L. reuteri) (DSM 17938) and Lactobacillus rhamnosus (L. rhamnosus) GG (ATCC 53103). Presence of dietary supplements affected antibiotic sensitivity of tested bacteria. Results of biochemical testing minimally changed. MICs of tested supplements have been determined as well, where L. reuteri tolerated higher concentrations of supplements compared to L. rhamnosus. Probiotic efficiency was also tested through bile and acid tolerance assays. Obtained results showed that presence of dietary supplements did not alter probiotic efficiency. According to other studies L. reuteri and L. rhamnosus form biofilm structures in the human gut, however they showed very low affinity to form biofilms before and after treatment with dietary supplements when tested in vitro. Previous studies showed that L. reuteri could be used in a treatment for autistic-spectrum disorders. According to results from this study, patients with ASD should avoid zinc in the form of capsules (as dietary supplements) from their diets, since it inhibits growth of L. reuteri. In general, tested dietary supplements, except zinc, did not affect bacterial properties on a large scale.