In vitro safety assessments and antimicrobial activities of Lactobacillus rhamnosus strains isolated from a fermented mare’s milk.

This research paper investigates the safety and antimicrobial activities of three strains of Lactobacillus rhamnosus, a type of bacteria found in fermented mare’s milk, with the potential to serve as probiotics. The most promising strain among them, FSMM15, is distinguished by its inability to bind plasminogen and effectively inhibiting the growth of some harmful bacteria despite lower acid production.

Research Objectives and Methods

• The research was aimed at the safety assessment and examination of antimicrobial activities of three Lactobacillus rhamnosus strains – FSMM15, FSMM22, and FSMM26 – isolated from fermented mare’s milk.
• The authors evaluated the susceptibility of these strains to different antibiotics, checked them for various enzymatic activities, and tested their effects on the growth of harmful bacteria.

Research Findings

• All three FSMM strains were found to be susceptible to ampicillin, gentamycin, kanamycin, streptomycin, tetracycline, and chloramphenicol. However, they were resistant to erythromycin and clindamycin.
• None of the strains showed positive bioconversion of bile salts, hemolytic activity, or mucin degradation activity. This means they do not have the ability to convert bile salts or destroy red blood cells or mucin, a protein present in mucus.
• Enzymatic activities of α-chymotrypsin and β-glucosidase were detected in these strains, while those of α-galactosidase, β-glucuronidase, and N-acetyl-β-glucosaminidase were not. These enzymes play different roles in our digestive process; the absence or presence of these enzymes can affect their potential as probiotics.
• Strain FSMM15 did not have plasminogen binding ability, an attribute that the researchers highlighted as making it a safe probiotic, as the binding of plasminogen can potentially lead to undesired effects such as blood clot dissolution.

Implications and Conclusion

• Despite lower acid production, FSMM15 was found to be effective in inhibiting the growth of harmful bacteria such as Salmonella Typhimurium LT-2, Shigella sonnei, Listeria monocytogenes, and Escherichia coli O157. This indicated that the strain could potentially be used as a probiotic.
• The authors concluded that strain FSMM15 offers a promising safety profile and efficacy in inhibiting the growth of several harmful bacteria, making it a potential candidate for probiotic applications.