Investigating lactic acid bacteria genus properties: Antioxidant activity, antibiotic resistance, and antibacterial activity against multidrug-resistant bacteria .

BACKGROUND

Lactic acid bacteria (LAB) are utilized as a starter culture in the manufacturing of fermented dairy items, as a preservative for various food products, and as a probiotic. In our country, some research has been carried out, even if LAB plays a principal role in food preservation and improves the texture and taste of fermented foods, that is why we tried to evaluate their probiotic effect. The objective of this research was to determine the antibacterial activity of ) against () ATCC 29213, investigate their antioxidant activity, and characterize their sensitivity against 18 antibiotics.

METHODS

A total of 23 LAB ( subsp. subsp. subsp. ) were isolated from cow's raw milk. The antibacterial activity was performed using two techniques, competition for nutrients and a technique utilizing components nature, using the disk diffusion method. The sensitivity of the studied LAB to different antibiotics was tested on Man rogosa sharp (MRS) agar using commercial antibiotic disks. All strains of LAB were examined for their antioxidant activity. The antioxidant activity of was tested by 2,2-diphenyl-1 picrylhydrazyl (DPPH).

RESULTS

The results showed that the MRS medium was more adapted than Muller Hinton Agar (MHA) to investigate the antibacterial activity of against ATCC 29213. Also, exhibited a notable degree of antibacterial activity against ATCC 29213. subsp. displayed higher antibacterial activities, followed by ssp. and lastly ssp. against ATCC 29213. Lc 26 among all strains of showed a high potential antibacterial activity reaching 40 ± 3 mm against ATCC 29213. All strains of showed a slightly moderate antioxidant activity (10.56 ± 1.28%-26.29 ± 0.05 %). The results of the antibiotic resistance test indicate that all strains of were resistant to cefotaxime, sulfamethoxazole-trimethoprim, and streptomycin and were sensitive to Ampicillin, Amoxicillin, Penicillin G, Teicoplanin, Vancomycin, Gentamicin 500, Tetracycline, and Chloramphenicol. These test results indicate that this strain falls within the criteria of not posing any harmful effects on human health. The important antibacterial properties recorded for all strains were derived from the production of antibacterial active metabolites, such as protein, diacetyl, hydrogen peroxide, and lactic acid, together with the fight for nutrients.

CONCLUSION

This study suggests that the strains of could be added as an antibacterial agent against ATCC 29213 and can provide an important nutritional property for their antioxidant potential.