A Study of Antimicrobial Effects of Reuterin by Lactobacillus reuteri DSM 17938 on Escherichia coli

Abstract

Background
The widespread antibiotic resistance is an imminent problem in today’s world. As the number of antibiotic resistance cases increase, it is inevitable to discover alternate treatment options. Probiotics could be one of the potentially important avenues which could be exploited to treat antibiotic resistance and other infections. The holistic approach of probiotics in exerting their beneficial characteristics not only makes it an attractive member in this regard, but also in providing essential nutrients to the host.

Results
Lactobacillus reuteri DSM 17938 is one of the most commonly used probiotics and so, the production of antimicrobial reuterin (3-hydroxypropionaldehyde) by the conversion of glycerol and its antagonistic effects on E.coli C600 were studied by co-culturing the microorganisms. Different growth media and analytical techniques such as HPLC, flow-cytometry were used to determine the qualitative and quantitative results of the reuterin production and its activity on the co-cultures. The experiments revealed that glycerol alone does not exhibit an inhibitory property on E.coli, but a concentration of 5g/L induced the production of lethal amounts of reuterin in L.reuteri grown together with E.coli in SD4 medium with galactose. It was also found that glycerol concentrations beyond 10 g/L will lead to lethal doses of reuterin for L.reuteri too.

Conclusion
Thus, the work showed an optimal amount of glycerol concentration imparting antagonistic effect through the antimicrobial reuterin in co-cultures.

Results
Secondly, to study the exocellular electron transfer between two microorganisms, an attempt to design a modified reactor setup to explore the co-culturing possibilities was accomplished. The co-culturing possibilities of L.reuteri and Prevotella copri in Schaedler anaerobe broth yielded results that need to be studied in detail further.

Conclusion
More investigations are required to design a medium where both microorganisms can be adequately grown on.

Popular Abstract

Since their discovery in the 20th century, antibiotics have played a major role in treating life-threatening, untreatable infections. For a long time, these life-saving drugs have been used and abused to their maximum extent and as a result, what was once thought as a powerful weapon of choice for the elimination of pathogens has now become nearly impotent because of the emergence of antibiotic resistance. As a consequence, the number of drug-resistant microorganisms have grown in size and have been spreading uncontrollably despite all efforts. Thus, antibiotic resistance is viewed as an ever-increasing threat to humanity and it challenges the very survival of all living creatures. This means that it is beyond question to discover alternate ways to combat the pathogenicity of virulent microorganisms. One of the possible ways is to use probiotics.

Probiotics like Lactobacillus reuteri are well-known for their beneficial effects on the host. Although probiotics are commercially marketed and available as functional foods and livestock feeds, their antimicrobial properties have been often overlooked. L.reuteri has been previously found to secrete an antimicrobial compound known as reuterin during the metabolic conversion of glycerol, which is proven to act against pathogenic microorganisms. In this work, the antibacterial activity on Escherichia coli effected by L.reuteri by the production of reuterin was studied.

The two organisms were co-cultured in a common medium at optimal conditions and reuterin production under varying glycerol concentrations was observed. The study revealed that at a certain concentration of glycerol, a lethal dose of reuterin on E.coli was produced by L.reuteri in the medium. This confirmed that the E.coli is susceptible to antagonistic effects of the antimicrobial reuterin. And as a probiotic, L.reuteri could be potentially used as a substitute for antibiotics in treating infections.

In addition, co-culturing opportunities of L.reuteri and Prevotella copri for exocellular electron transfer between the two species were explored by designing a modified bioreactor setup. The experiments showed that a medium that nourishes both bacteria and help them grow should be formulated and the culture conditions should be optimized. Therefore, it was evident that is possible to co-culture and at the same time, more basic studies need to be carried out before co-culturing of the aforementioned microorganisms.

• author: John Napolean, Charlton Leny
• supervisor: Christer Larsson
• organization: Applied Microbiology; Biotechnology
• course: KMBM01 20191
• year: 2019
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Probiotics, Lactobacillus reuteri, L. reuteri, Escherichia coli, E. coli, Reuterin, 3 hydroxypropianaldehyde, 3-HPA, Applied Microbiology, Teknisk Mikrobiologi, probiotika, DSM 17938, Prevotella copri, bioreactor, fermentation, bioteknik, Biotechnology
• language: English
• id: 8996582
• date added to LUP: 2019-10-22 09:10:57
• date last changed: 2019-10-22 09:10:57