Abstract
The elderly population living in nursing homes is particularly vulnerable to COVID-19 although individual susceptibility to SARS-CoV-2 infection may be related to the host microbiota. The objective of this work was to investigate the effect of Ligilactobacillus salivarius MP101 on the functional (Barthel index), cognitive (GDS/FAST), and nutritional (MNA) status as well as on the nasal and fecal inflammatory profiles of elderly residents living in a nursing home that is highly affected by COVID-19. A total of 25 residents participated in the trial, which involved the daily ingestion of a dairy product (L. salivarius MP101: 9.3 log10 CFU per unit) for 4 months. Nasal and fecal samples were analyzed for 37 immune factors at recruitment and at the end of the study. After the trial, no change in the GDS/FAST scores were found but, in contrast, the values for the Barthel index and the MNA score improved significantly. The concentrations of some immune factors changed significantly after the trial, including a decrease in the concentrations of BAFF/TNFSF13B, APRIL/TNFSF13, IL8, IL31, osteopontin, sTNF-R1, and sTNF-R2, and an increase in chitinase 3-like 1, IL19, IL35, and pentraxin 3 was also observed. In conclusion, L. salivarius MP101 seems to be a promising strain for improving or maintaining health in this highly vulnerable population.
Highlights
Severe Acute Respiratory Syndrome Coronavirus 2, universally known as SARS-CoV2, was first identified in 2019 as the causative agent of a new acute respiratory disease, which was recognized as a pandemic by the World Health Organization on 11 March 2020
The fact that SARS-CoV-2 initially interacts with the mucosal epithelia associated with a complex microbiota and that its mechanism of infection is related to the angiotensin-converting enzyme receptor 2 (ACE2), whose activity is influenced and, in turn, influences the microbiota of the upper respiratory and gastrointestinal tracts [1,2], suggests an implication of the microbiota in individual susceptibility to COVID-19 and in the severity of the infection [3,4]
Microbial growth was only observed on the Man Rogosa and Sharpe (MRS) plates, and no growth was detected on the remaining media (PEMBA, MCK, Columbia nalidixic acid (CNA), Sabouraud chloramphenicol dextrose (SDC)) used to control the purity of the developed product
Summary
Severe Acute Respiratory Syndrome Coronavirus 2, universally known as SARS-CoV2, was first identified in 2019 as the causative agent of a new acute respiratory disease (coronavirus disease 2019; COVID-19), which was recognized as a pandemic by the World Health Organization on 11 March 2020. The severity of the disease is higher among people aged ≥60 years; people with underlying health conditions, such as hypertension, diabetes, obesity, cardiovascular disease, chronic respiratory disease and weakened immune systems; and/or those living in long-term care facilities Most of those infected remain asymptomatic, a fact that complicates the control of the disease. The modulatory role of the respiratory microbiota has already been observed with other respiratory viruses, including other coronaviruses and the respiratory syncytial virus [5,6,7] In this sense, it has been postulated that people with “eubiotic” respiratory and gastrointestinal microbiotas would be more likely to have an asymptomatic or mild SARS-CoV-2 infection given that their microbiotas are associated with appropriate mucosal immune responses. People with respiratory or intestinal dysbiosis would not be able to develop the correct responses and would be more prone to a more severe infection and to complications (including cytokine storm, bacterial and fungal secondary infections, and sepsis) [8,9]
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