Interakcije bakterij vrst Campylobacter jejuni in Bacillus subtilis

Krapež, Katarina (author), Klančnik, Anja (mentor)

Zaradi naraščanja črevesnih okužb ljudi in živali, ki jih povzročajo bakterije Campylobacter jejuni in njihova vse večja odpornost proti antibiotikom, so bile predlagane številne alternativne strategije nadzora okužb in zmanjšanja prisotnosti bakterij. Ena od novejših alternativnih strategij nadzora in zmanjšanja prisotnosti termotolerantnih bakterij C. jejuni v prebavnem traktu piščancev vključuje dodatek probiotičnih bakterij v krmo, med katere sodijo tudi bakterije Bacillus subtilis. Pri tem v črevesju ljudi in živali prihaja do intenzivnih interakcij med bakterijami, ki pa so slabo raziskane. Interakcije med bakterijami C. jejuni ter B. subtilis smo preučevali v ko-kultivaciji in ko-adheziji bakterij C. jejuni in B. subtilis pod različnimi pogoji ter ovrednotili število kolonijskih enot v mono-kulturi ter v ko-kulturi obeh bakterij. Ko-kultivacija bakterij C. jejuni in B. subtilis ni vplivala na rast bakterij B. subtilis.Vplivala je na rast bakterij C. jejuni. Ko-kultivacija pri pogojih, ki omogočajo kampilobaktrom rast (mikroaerofilna atmosfera, 37 °C ali 42 °C) je zmanjšala preživelost bakterij C. jejuni. Nasprotno pa je ko-kultivacija pri pogojih, ki za rast kampilobaktrov niso optimalni (aerobna atmosfera, 20 °C ali 37 °C) zaščitno vplivala na njihovo preživetje. Ko-adhezija bakterij C. jejuni in B. subtilis na abiotski polistirenski površini je prav tako vplivala na adhezijo bakterij C. jejuni, saj je zmanjšala število adheriranih kampilobaktrov. Ocenili smo tudi znotrajcelično oksidacijo preko spremljanja tvorbe ROS, aktivnost bakterijskih celic preko luminiscence prisotnega ATP ter vpliv izrabljenih gojišč bakterij B. subtilis na membransko integriteto bakterij C. jejuni. Večji nastanek ROS in posledično močnejši oksidativni stres je bil v ko-kulturi bakterij. Pri tem se je aktivnost ko-kulture zmanjšale le pri nekaterih pogojih. Ugotovili smo, da izrabljena gojišča bakterij B. subtilis zmanjšajo membransko integriteto bakterij C. jejuni, a imajo neznaten vpliv na zmanjšanje preživelosti bakterij C. jejuni. S poskusom smo dokazali, da lahko bakterije B. subtilis zmanjšajo prisotnost bakterij C. jejuni, kar predstavlja učinkovito strategijo omejevanja okužb z bakterijami C. jejuni.

• Language: Slovenian
• Keywords: bakterijske interakcije, Campylobacter jejuni, Bacillus subtilis, ko-kultivacija, ko-adhezija, fitnes bakterij, oksidativni stres, aktivnost bakterij, membranska integriteta
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [K. Krapež]
• Year: 2018
• PID: 20.500.12556/RUL-103825
• UDC: 579.24/.26
• COBISS.SI-ID: 4961656
• Publication date in RUL: 27.09.2018

Secondary language

• Language: English
• Title: The interactions of bacteria Campylobacter jejuni and Bacillus subtilis

Abstract

Because of the increase of intestinal diseases in humans and animals, caused by Campylobacter jejuni and their increasing resistance to antibiotics, a number of alternative strategies for controlling infections and reducing the presence of bacteria have been proposed. One of the new alternative strategies for control and reduction of thermotolerant species C. jejuni in the gastrointestinal tract of chickens includes the addition of probiotic bacteria, which also include Bacillus subtilis. These interactions between bacteria in the intestines of humans and animals are poorly researched. We studied interactions between C. jejuni and B. subtilis in co-culture and co-adhesion under various conditions and evaluated the number of colony units in the mono-culture and co-culture of both bacteria. The co-cultivation C. jejuni and B. subtilis did not affect the growth of B. subtilis, but it affected the growth of C. jejuni. Co-cultivation in conditions that allow campylobacter growth (microaerophilic atmosphere, 37 °C or 42 °C), reduced the survival of C. jejuni. On the other hand, co-cultivation in the conditions that are not optimal for the growth of campylobacter (aerobic atmosphere, 20 °C or 37 °C), had a protective effect on their survival. Co-adhesion C. jejuni and B. subtilis also affected the adhesions of C. jejuni on the abiotic polystyrene surface, as it reduced the number of adhered campylobacters. We also evaluated intracellular oxidation by monitoring the formation of ROS, the activity of bacterial cells via luminescence of the present ATP and the influence of the spent medium B. subtilis on the membrane integrity of C. jejuni. The increased formation of ROS and consequently higher oxidative stress was in the co-culture of bacteria. In this case, the activity of co-culture decreased only under certain conditions. We discovered, that the spent medium of B. subtilis reduced the membrane integrity of C. jejuni, but had a minor effect on the reduction of C. jejuni. By experiment, we have demonstrated that B. subtilis can reduce the presence of C. jejuni and therefore represents an effective strategy for limiting infections with C. jejuni.

• Keywords: bacterial interactions, Campylobacter jejuni, Bacillus subtilis, co-cultivation, co-adhesion, bacterial fitness, oxidative stress, bacterial activity, membrane integrity