Identification, antibacterial and antifungal effects, antibiotic resistance of some lactic acid bacteria

Abstract

A total of 74 lactic acid bacteria (LAB) isolates were obtained from yoghurt, cheese, raw milk, boza and whey. 36 strains were identified at species levels as Lactococcus lactis (15), Lc. garvieae (8) Lactobacillus plantarum (7), Enterococcus faecium (3), Leuconostoc citreum (2) and Lb.casei (1) by MALDI-TOF MS analysis. The strains were tested for antimicrobial properties using disc diffusion method against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Cronobacter sakazakii, Bacillus cereus and Salmonella Typhimurium. 18 strains from available samples showed antimicrobial activity. Formation zones were appeared from 7 mm to 19 mm against all bacteria, except B. cereus. Additionally, antibiotic susceptibility of these 18 strains were investigated and strains related to 18 LAB were found resistant despite of 72.2% rifampicin, 53.3% tetracycline and vancomycin, 27.7% to erythromycin and nitrofurantoin. In this study, we investigated antifungal effects of the strains. LAB were screened for antifungal effects by using dual agar overlay against mycotoxigenic Aspergillus candidus, Cladosporium cladosporioides, Cladosporium sphaerospermum, Mucor hiemalis, Ulocladium chartarum, Aspergillus niger and Penicillium expansum. 18 LAB isolates showed antifungal effects. As a result, Enterococcus faecium has antimicrobial and antifungal properties, and therefore, it can be used under various experimental conditions in future studies.

Immobilization of Lactic acid bacteria for production of extracellular polysaccharides

“…EPS produced by LAB have recently received increasing attention because of their health benefits to the consumers (Ishiguro et al, 2017;Mejia-Gomez & Balcázar, 2020). EPS produced by LAB possess various potential health benefits and have important functional roles in human or animal health including immunomodulatory properties, anti-cancer, antioxidant activity, anti-ulcer (Abid et al, 2018;Deepak et al, 2016;Zhang et al, 2015), anti-biofilm agents to prevent adhesion of pathogenic bacteria, blood glucose (Oleksy & Klewicka, 2018;Kanak & Yilmaz, 2021;Pato et al, 2021) and cholesterol lowering properties (Korcz et al, 2018), and antihypertensive activity (Harutoshi, 2013). Although some EPS form biofilms that cause hygiene problems, other EPS derived from LAB play a crucial role in improving the rheology, texture, and mouthfeel of fermented food formulations in the food industry (Dilna et al, 2015;Lee et al, 2011).…”

Isolation, identification, and fermentation characteristics of endogenous lactic acid bacteria derived from edible mushrooms

“…The purified strains were tested by hydrogen peroxide reaction and Gram staining. The bacteria with positive Gram staining and negative catalase could be preliminarily identified as LAB (Kanak & Yilmaz, 2021). In brief, the inoculation ring was used to drop a small amount of bacterial solution on the slope plate, 3% of hydrogen peroxide solution was dropped and mixed.…”

Metabolites from Lactococcus lactis subsp. lactis: Isolation, Structure Elucidation, and Antimicrobial Activity

“…29,30 Besides, antifungal activity against Aspergillus niger, Penicillium chrysogenum, Fusarium oxysporum, 15 F. verticillioides, 31 Colletotrichum capsici, 32 Penicillium expansum, Cladosporium cladosporioides, Mucor hiemalis, and Ulocladium chartarum has been reported. 33 Culture and Fermentation Conditions. The strain BIONCL 17752 was subcultured on MRS agar plates and grown at 37 °C for 48 h. A pure single colony was transferred into 50 mL of MRS broth.…”