AUTHOR=Dezaki Farid Shirmardi , Narimani Tahmineh , Ghanadian Mustafa , Bidram Elham , Poursina Farkhondeh 

TITLE=Antimicrobial and antibiofilm effects of cyclic dipeptide-rich fraction from Lactobacillus plantarum loaded on graphene oxide nanosheets

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1391039

DOI=10.3389/fmicb.2024.1391039

ISSN=1664-302X

ABSTRACT=<sec id="sec80"><title>Introduction</title><p>One effective method to combat bacterial infections is by using bacteria itself as a weapon. <italic>Lactobacillus</italic> is a type of fermenting bacterium that has probiotic properties and has demonstrated antimicrobial benefits against other bacteria. Cyclodipeptides (CDPs), present in the supernatant of <italic>Lactobacillus</italic>, possess several antimicrobial properties.</p></sec><sec id="sec81"><title>Methods</title><p>In this study, the CDP fraction was isolated from the supernatant of <italic>Lactobacillus plantarum</italic> (<italic>L. plantarum</italic>). This fraction was then loaded onto graphene oxide nanosheets (GO NSs). The study assessed the substance’s ability to inhibit bacterial growth by using the minimum inhibitory concentration (MIC) method on <italic>A. baumannii</italic> and <italic>S. aureus</italic> strains that were obtained from clinical samples. To determine the substance’s impact on biofilm formation, the microtiter plate method was used. Moreover, the checkerboard technique was employed to explore the potential synergistic effects of these two substances.</p></sec><sec id="sec82"><title>Results and discussion</title><p>According to the study, the minimum inhibitory concentration (MIC) of the desired compound was found to be 1.25 mg/mL against <italic>S. aureus</italic> and 2.5 mg/mL against <italic>A. baumannii</italic>. Furthermore, at a concentration of 10 mg/mL, the compound prevented 81.6% (<italic>p</italic> &lt; 0.01) of biofilm production in <italic>A. baumannii</italic>, while at a concentration of 1.25 mg/mL, it prevented 47.5% (<italic>p</italic> &lt; 0.05) of biofilm production in <italic>S. aureus</italic>. The study also explored the synergistic properties of two compounds using the checkerboard method.</p></sec><sec id="sec83"><title>Conclusion</title><p>In general, we found that GO NSs possess antimicrobial properties and enhance cyclodipeptides’ activity against <italic>S. aureus</italic> and <italic>A. baumannii</italic>.</p></sec>