Interplay between viral infections and gut microbiota dysbiosis: Mechanisms and therapeutic potential

Table 5 Therapeutic effects of probiotic supplementation on infectious disease outcomes

Probiotic/strain	Virus	Model	Individuality	Mechanism against viral infection	Ref.
Lactobacillus casei 393	HIV-1 (pseudovirus)	In vitro (TZM-bl cells)	HIV-infected adults	Expresses CD4; binds HIV-1 pseudovirus; ↓ infection approximately 60%-70%	[138]
Lactobacillus rhamnosus GR-1 and L. reuteri RC-14	HIV	Clinical (24 adult women)	HIV-infected women	Resolved diarrhea; ↑/stable CD4 in 11/12 vs 3/12 control	[139]
Lactobacillus acidophilus ATCC 4356 engineered with human CD4 (in yogurt)	HIV-1	In vitro & humanized BLT mice	HIV-infected women (Nigeria)	Surface CD4 binds HIV gp120; blocks viral entry	[140]
Lactobacillus casei Shirota (in fermented milk)	HIV	Clinical (children, n = 60)	HIV-infected Vietnamese children	↑ CD4+, Th2, Th17; ↓ Tregs, CD8+ activation; ↓ viral load	[141]
Lactobacillus casei Shirota	EBV, CMV (herpesviruses)	Clinical (athletes)	Healthy athletes	↓ Plasma EBV and CMV IgG titres in seropositive individuals suggest improved immune control of viral reactivation	[142]
Lactobacillus rhamnosus GG	Rotavirus, Cryptosporidium	Clinical (children)	Children with gastroenteritis	Improved intestinal barrier function (↓ L:M ratio); ↑ serum IgG (rotavirus); ↓ reinfection rates in rotavirus-positive children	[143]
Lactobacillus casei Shirota	Norovirus	Clinical (elderly)	Older adults in a care facility	Shortened fever duration; modulated gut microbiota (↑ Lactobacillus, Bifidobacterium; ↓ Enterobacteriaceae); ↑ acetic acid	[144]
Lactobacillus rhamnosus GG	Rhinovirus	Clinical (infants)	Preterm infants (32-36 weeks)	↓ RTI incidence, ↓ rhinovirus infections; no effect on severity or shedding	[145]
Enterococcus faecium NCIMB 10415	Swine influenza A (H1N1, H3N2)	In vitro (cell culture)	Porcine macrophage and epithelial cells	↓ Virus titers (up to 4-log); ↑ cell viability; ↑ NO release; ↓ TNF-α, IL-6, TLR3; ↑ IL-10, IFN-α; direct virus trapping by bacteria	[146]
Bifidobacterium longum BB536	Influenza	Clinical (elderly)	Elderly (mean age 86.7 years)	↓ Influenza and fever incidence, ↑ NK cell activity and neutrophil bactericidal activity; maintained innate immunity	[147]
Bifidobacterium adolescentis SPM0212	HBV	In vitro (HepG2.2.15 cells)	Human hepatocyte-derived cell line	↓ HBsAg and extracellular HBV DNA; ↑ MxA, STAT1 expression via IFN pathway; active antiviral components < 30 kDa	[148]
Bifidobacterium lactis DSM 32246, Bifidobacterium lactis DSM 32247, Lactobacillus acidophilus DSM 32241, Lactobacillus brevis DSM 27961, Lactobacillus helveticus DSM 322426	SARS-CoV-2	Clinical (hospitalized)	Hospitalized COVID-19 patients (Italy, n = 70)	↓ Progression to respiratory failure; ↑ symptom resolution (fever, diarrhea, dyspnea); ↓ ICU admission and mortality; modulation of gut-lung axis; potential ↑ Nrf2/HO-1 antiviral pathways	[149]
Lactobacillus gasseri SBT2055	RSV	In vivo and in vitro	BALB/c mice and HEp-2 cells	↓ RSV titer; ↓ IL-6, TNF-α, IL-1β, CCL2; ↑ IFN-β, IFN-γ, OAS1a, ISG15; ↓ SRCAP expression linked to RSV replication	[150]

HIV: Human immunodeficiency virus; BLT: Bone marrow-liver-thymus; Th: T helper; Tregs: Regulatory T cells; EBV: Epstein-Barr virus; CMV: Cytomegalovirus; IgG: Immunoglobulin G; L:M: Lactulose:mannitol; RTI: Respiratory tract infection; TNF: Tumor necrosis factor; IL: Interleukin; TLR: Toll-like receptor; IFN: Interferon; NK: Natural killer; HBV: Hepatitis B virus; HBsAg: Hepatitis B surface antigen; MxA: Myxovirus protein A; STAT1: Signal transducer and activator of transcription 1; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2; COVID-19: Coronavirus disease 2019; ICU: Intensive care unit; Nrf2: Nuclear factor erythroid 2-related factor 2; HO-1: Heme oxygenase-1; RSV: Respiratory syncytial virus; CCL2: C-C motif ligand 2; OAS1a: Oligoadenylate synthetase 1a; ISG15: Interferon-stimulated gene product 15.