Role of Probiotics as Therapeutic Strategy to Prevent Progression of COVID-19 Infections

It is known that the entry points for the virus into the body are angiotensin-converting enzyme 2 (ACE2) receptors - proteins that are linked to intestinal cells. It is also expected that coronaviruses constantly modify their binding patterns as they evolve, and their potential target binding site in the lungs may vary, unlike in the small intestine, where it is unchanged

The enterocytes could, therefore, represent a reservoir for coronaviruses. In the acute phase, only about 10% of COVID-19 patients present virus complementary DNA (c DNA) in the blood, while almost 50% of them excrete it in the stools, thus, suggesting orofecal route as a potential mode of contamination (4)

Intestinal dysbiosis has a significant immune impact on the pulmonary system (5) , possibly making it an

additional risk for respiratory distress induced by COVID-19.

The objective of the study was to assess the possible role of oral probiotic therapy as a complementary therapeutic strategy to prevent the progression of COVID-19 infections. The study was conducted in Italy while it was fighting the epicentre of the pandemic.

All the patients (n= 70) with a median age of 59 years, were positive for COVID-19 and met the clinical criteria consisting of fever > 37.5◦C, requiring non-invasive oxygen therapy, and having involvement of more than 50% lung indicated by CT imaging. The enrolled patients were diagnosed with symptomatic COVID-19 disease, which, however, at the time of evaluation did not require endotracheal intubation and invasive mechanical ventilation.

Clinical presentation of included patients at the time of hospital admission included fever (94.3%), cough (77.1%), dyspnoea (62.9%), headache (15.7%), asthenia (21.4%), myalgia (5.7%) and diarrhoea (47.1%).

Dyspnoea was defined as "a subjective experience of breathing discomfort that consisted of qualitatively distinct sensations that vary in intensity" (6) . Acute diarrhoea was defined as a stool with increased water content, volume, or frequency that lasted <14 days (7) . High-resolution CT scan was used to identify lung involvement. Typical CT findings of COVID-19 are ground-glass opacities, consolidation, reticular or crazy paving pattern (8)

Oxygen therapy was delivered via a Venturi mask in spontaneous breathing patients. If hypoxemia persisted, continuous positive airway pressure (CPAP) was administered. Patients with severe acute hypoxemia and in need of invasive mechanical ventilation were referred to the Intensive Care Unit (ICU).

All the patients included in the study were treated with hydroxychloroquine (HCQ) 200mg bid, antibiotics (azithromycin 500 mg) and Tocilizumab (TCZ) dosage is 8 mg/kg (up to a maximum of 800 mg per dose) 12 hourly two times daily, along with oxygen.

In addition to this standard care, patients were randomly selected and divided into two groups. A group of 28 subjects received oral probiotic therapy containing bacterial probiotic strains, referred to as (OB+) group, while another group of 42 individuals were not supplemented with any probiotic supplementation (OB–) formed the comparator group.

No statistically significant differences were observed between the (OB+) group and the (OB–) concerning demographics, liver enzymes and Charlson comorbidity index at baseline. Along the same lines, no major differences between groups were found across clinical and respiratory presentations. All patients had clinical and radiological signs compatible with COVID-19 pneumonia and needed respiratory assistance in the hospital setting but not resuscitation support.

The two groups of patients were homogeneous with regard to the proportion of subjects needing non-invasive oxygen support delivered via Venturi mask in spontaneous breathing or by continuous positive airway pressure (CPAP).

For each patient, the Charlson comorbidity index (9) , oxygen support requirement, as well as, laboratory values comprising alanine aminotransferase (ALT), aspartate aminotransferase (ALT), haemoglobin (Hb), pH, hydrogen carbonate (HCO3), lactic acid and partial pressure of arterial carbon dioxide (PaCO2) were determined at baseline.

The observed partial pressure of arterial oxygen (PaO2), a fraction of inspired oxygen (FiO2), the disappearance of symptoms associated to COVID-19, adverse events, and the number of patients transferred to ICU were collected at 24 hours (h), 48 hours, 72 hours, and 7 days from initiation of oral probiotic therapy and hospitalizations for all patients independently of treatment. Patients were considered positive for respiratory failure when the determined PaO2/FiO2 ratio was <300.

The formulation administered in this study contained predominant genus Lactobacillus strains: consisting of Streptococcus thermophilus DSM 32345, L.acidophilus DSM 32241, L. helveticus DSM 32242, L. paracasei DSM 32243, L. plantarum DSM 32244, L. brevis DSM 27961, B. lactis DSM 32246, B. lactis DSM 32247. The oral probiotic treatment involved the use of 2,400 billion bacteria per day, administered in three equal doses.

The oral probiotic administration was associated with recovery from diarrhoea in all the patients within 7 days. Interestingly, a large proportion of probiotic treated patients (42.9%) were resolved from diarrhoea within 24 hours and almost completely (92.9%) within 3 days.

Also, the other signs and symptoms indicative of general vitality like fever, asthenia, headache, myalgia and dyspnoea, considered cumulatively presented with a similar trend of improvement, more evident from the second day of probiotic treatment.

Analysing the respiratory outcomes, by applying the General Linear Mixed Model (GLIMMIX), it was demonstrated that there was a significant difference in the evolution of respiratory outcomes between the probiotic treated and untreated groups (p <0.001).

After 7 days of treatment, there was a significant eight-fold decreased risk of evolution to respiratory failure in oral probiotics treated group. The need of resuscitation support i.e., the requirement for prone ventilation or extracorporeal membrane oxygenation (ECMO) for patients administered with oral probiotics therapy (OB+) group was significantly less in comparison to patients in (OB–) group

The liver enzymes, renal functions and QT interval were monitored carefully. The propensity of the QT interval prolongation was increased in patients treated with  azithromycin. No adverse events were recorded.

The observed prevalence of patients with lethal outcomes within the control group was in line with that (mean ± SD 9.4 ± 1.7%) recorded in Italy during the same period (March - April 2020) (10) . It is noteworthy that all patients treated with oral probiotic therapy survived the COVID- 19 illness, and none required invasive mechanical ventilation and ICU admission.

• Within 72 hours, nearly all the patients treated with oral probiotic treatment showed remission of diarrhoea and other symptoms as compared to just less than half in the non-supplemented group

• The frequency of patients transferred to ICU and mortality were higher among the patients not treated with oral probiotic treatment

• The predominant strains used for treatment in the oral probiotic complex belonged the genus Lactobacillus

• The positive results of this study further reinforce the importance of gut-lung axis in controlling COVID-19 infections.

This study was an endeavour towards repurposing the scope of probiotics through physiological rationale – an initiative aimed to modulate the gut-lung axis, facilitate patient management and possibly determine the outcome of lung infection in COVID-19 patients. The study indicates that oral probiotic treatment has demonstrated a statistically significant impact on clinical and in-hospital recovery, reduced ICU transfers, and improved respiratory outcomes in COVID-19 patients. The study serves as a valuable benchmark at providing an interim suggestion for improving the management of the COVID-19 illness through consideration of the use of probiotics. (3) The predominant strains used in the treatment group belonged to the Lactobacillus genus.

Adapted from:

1 Li Q, Guan X,WuP, et al. Early Transmission Dynamics in Wuhan,China, of Novel Coronavirus-Infected Pneumonia. N Engl J Med 2020;382:1199–207.

2 Saber-Ayad M, Saleh MA, Abu-Gharbieh E. The Rationale for Potential Pharmacotherapy of COVID-19. Pharmaceuticals (Basel). 2020;13(5):96. Published 2020 May 14. doi:10.3390/ph13050096

3 d'Ettorre G, Ceccarelli G, Marazzato M, Campagna G, Pinacchio C, Alessandri F, Ruberto F, Rossi G, Celani L, Scagnolari C, Mastropietro C, Trinchieri V, Recchia GE, Mauro V, Antonelli G, Pugliese F, Mastroianni CM. Challenges in the Management of SARS-CoV2 Infection: The Role of Oral Bacteriotherapy as Complementary Therapeutic Strategy to Avoid the Progression of COVID-19. Front Med (Lausanne). 2020 Jul 7;7:389. doi: 10.3389/fmed.2020.00389. PMID: 32733907; PMCID: PMC7358304.

4 Feng Z, Wang Y, Qi W. The small intestine, an underestimated site of SARS-CoV-2 infection: from red queen effect to probiotics. Preprints. (2020). doi: 10.20944/preprints202003.0161.v1

5 Chiu L, Bazin T, Truchetet ME, Schaeverbeke T, Delhaes L, Pradeu T. Protective microbiota: from localized ton long-reaching co-immunity. Front Immunol. (2017) 8:1678. doi: 10.3389/fimmu.2017.01678

6 Laviolette L, Laveneziana P. Dyspnoea: a multidimensional and multidisciplinary approach. Eur Respir J. (2014) 43:1750– 62. doi: 10.1183/09031936.00092613

7 BarrW, Smith A. Acute diarrhea. Am Fam Physician. (2014) 89:180–9.

8 Ye Z, Zhang Y, Wang Y, et al. Chest CT manifestations of new coronavirus disease 2019 (COVID-19): a pictorial review. Eur Radiol. (2020) 1–9. doi: 10.1007/s00330-020-06801-0.

9 Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis. (1987) 40:373–83. doi: 10.1016/0021-9681(87) 90171-8

10 Source: Italian Civil Protection Department. Available online at: http://opendatadpc.maps.arcgis.com/apps/opsdashboard/index.html#/ b0c68bce2cce478eaac82fe38d4138b1 (accessed April 10, 2020).