Protective Action of L. salivarius SGL03 and Lactoferrin against COVID-19 Infections in Human Nasopharynx

Abstract

In this study, we used live viral particles from oral secretions from 17 people infected with SARS-CoV-2 and from 17 healthy volunteers, which were plated on a suitable medium complete for all microorganisms and minimal for L.salivarius growth. Both types of media also contained an appropriately prepared vector system pGEM-5Zf (+) based on the lactose operon (beta-galactosidase system). Incubation was carried out on both types of media for 24 h with the addition of 200 μL of Salistat SGL03 solution in order to test its inhibitory effect on the coronavirus contained in the oral mucosa and nasopharynx, visible as light blue virus particles on the test plates, which gradually disappeared in the material collected from infected persons over time. Regardless of the conducted experiments, swabs were additionally taken from the nasopharynx of infected and healthy people after rinsing the throat and oral mucosa with Salistat SGL03. In both types of experiments, after 24 h of incubation on appropriate media with biological material, we did not find any virus particles. Results were also confirmed by MIC and MBC tests. Results prove that lactoferrin, as one of the ingredients of the preparation, is probably a factor that blocks the attachment of virus particles to the host cells, determining its anti-viral properties. The conducted preliminary experiments constitute a very promising model for further research on the anti-viral properties of the ingredients contained in the Salistat SGL03 dietary supplement.

Keywords: COVID-19; L. salivarius; Salistat SGL03; human nasopharynx; lactoferrin.

Figure 1

The human oral cavity and nasopharynx to which particles of SARS-CoV-2 attach https://www.researchgate.net/publication/342577883, accessed on 3 June 2021.

Figure 2

Schematic presentation on experiments part 2.

Figure 3

Schematic presentation on experiments part 1 [57,74].

Figure 4

Petri dishes with biological materials of nasopharyngeal secretions from infected virus Sars-CoV-2 patients after 0–24 h incubation treatment with Salistat SGL03 (see Section 2.1).

Figure 5

The survivability of SARS-CoV-2 isolated from the patients’ nasopharynx of infected individuals after Salistat SGL03 treatment on specific media plates. Series from 1 to 17 number of individual study participants (infected persons by SARS-CoV-2), (see Section 2.1).

Figure 6

SARS-CoV-2 virus collected from the nasopharynx, after 24 h incubation. Viral inoculum were collected from healthy volunteers and individuals infected by SARS-CoV-2 of the nasopharynx, and were plated on both types of medium complete and selection medium (A–C).

Figure 7

Effect of lactoferrin present in probiotics on inhibition of viral particle growth from people infected with COVID-19 from nasopharynx after 24 h of incubation. Statistical significance at p < 0.05 *.

Figure 8

Virus particle analysis using MIC and MBC tests (A: healthy volunteers), (B: infected individuals with SARS-CoV-2). MBC analysis of tested viral particles (C: healthy volunteers) and (D: infected individuals with SARS-CoV-2. Lanes from 1 to 17—viral particles with serial dilutions after Salistat SGL03 treatment.

Figure 9

Virus particle analysis using MIC test (panel A: healthy volunteers without SARS-CoV-2) and (panel B: healthy volunteers after treatment of Salistat SGL03). Statistical significance vs. control in all analyzed samples were at * p < 0.05. X-axis number of study participants from 1 to 17.

Figure 10

Virus particle analysis using MIC test (panel A- infected volunteers with SARS-CoV-2) and (panel B- infected volunteers after treatment of Salistat SGL03). Statistical significance vs. control in all analyzed samples were at * p < 0.05. X-axis number of study participants from 1 to 17.

Figure 11

Virus particle analysis using MBC test (panel A- healthy volunteers without SARS-CoV-2) and (panel B- healthy volunteers after treatment of Salistat SGL03). Statistical significance vs. control in all analyzed samples were at * p < 0.05. X-axis number of study participants from 1 to 17.

Figure 12

Virus particle analysis using MBC test (panel A- infected volunteers without SARS-CoV-2) and (panel B- infected volunteers after treatment of Salistat SGL03). Statistical significance vs. control in all analyzed samples were at * p < 0.05. X-axis number of study participants from 1 to 17.