Mycotoxins adsorption by microorganisms isolated from Kefir grains

ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)A novel alternative for mycotoxins decontamination is the use of microorganisms that bind mycotoxins and reduce their gastrointestinal absorption. Lactic acid bacteria and yeasts were isolated from a Kefir culture and evaluated for their mycotoxin adsorption and biotransformation ability. Strains with high binding ability were identified based on DNA sequenci ng. The binding stability was determined by washing the complexes microorganism/mycotoxin with buffer solutions to simulate the pH conditions in the gastrointestinal tract. The results indicate that the microorganism consortium of Kefir grains adsorbed 82 to 100% of aflatoxin B 1(AFB1), zearalenone (ZEA) and ochratoxin A (OTA) when cultivated in milk. The most effective strains in adsorbing the mycotoxins were identified as Lactobacillus kefiri, Kazachstania servazzii and Acetobacter syzygii. The strains L. kefiri KFLM3 was able to adsorb 80 to 100% of the mycotoxins when cultivated in milk. However, desorption experiments showed that yeast K. servazzii KFGY7 retained more mycotoxin (65, 69 and 67% for AFB 1, OTA and ZEA, respectively) in the cells. Our findings revealed that kefir consumption can possibly reduce gastrointestinal absorption of these mycotoxins and consequently reduce their toxic effects. These Kefir isolates are promising for the development of fermented dairy products for human consumptionGrant UMINHO/BPD/51/2015 from project UID/BIO/04469/2013 financed by FCT/MEC (OE). This study was supported by FCT under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2 020 (POCI-01-0145-FEDER-006684); of BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope f orte2020 -Programa Operacional Regional do Norte; and under the scope of the projects RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER- 027462)info:eu-repo/semantics/publishedVersio

Modulation of drug resistance and biofilm formation of Staphylococcus aureus isolated from the oral cavity of Tunisian children

Objectives: This study aims to investigate the antimicrobial and the anti-biofilm activities of Lactobacillus plantarum extract (LPE) against a panel of oral Staphylococcus aureus (n = 9) and S. aureus ATCC 25923. The in vitro ability of LPE to modulate bacterial resistance to tetracycline, benzalchonium chloride, and chlorhexidine were tested also. Methods: The minimum inhibitory concentrations (MICs) and the minimal bactericidal concentrations of Lactobacillus plantarum extract, tetracycline, benzalchonium chloride and clohrhexidine were determined in absence and in presence of a sub-MIC doses of LPE (1/2 MIC). In addition, the LPE potential to inhibit biofilm formation was assessed by microtiter plate and atomic force microscopy assays. Statistical analysis was performed on SPSS v. 17.0 software using Friedman test and Wilcoxon signed ranks test. These tests were used to assess inter-group difference (p < 0.05). Results: Our results revealed that LPE exhibited a significant antimicrobial and anti-biofilm activities against the tested strains. A synergistic effect of LPEs and drug susceptibility was observed with a 2–8-fold reduction. Conclusion: LPE may be considered to have resistance-modifying activity. A more detailed investigation is necessary to determine the active compound responsible for therapeutic and disinfectant modulation. Keywords: Antibacterial, Staphylococcus aureus, Biofilm, Antibiotics, Synergetic, Lactobacillu