3 Interview 05/20 Prevotella & endemic TB might explain low COVID 19 deaths in India- Sandeep Chakraborty by Rajeev Chitguppi, Dental Tribune South Asia no mention of it in the paper. So, in that sense this is verified. on science, peptides. With experts trying to find the possible reasons for the low COVID related death rate in India, a hypothesis by Sandeep Chakraborty has generated considerable interest because of the data based explanation it offers. Sandeep Chakraborty (B-Tech, Electrical Engineering IIT Kharagpur, 1997), (Masters. Computer IIT Kharagpur, 2008) is a researcher focused computational protein modelling, genome projects, and designing anti- microbial His hypothesis based on his current research and data analysis on COVID-19 pathogenesis suggests that it‘s Prevotella - the anaerobic bacteria that might be responsible for the systemic complications seen in COVID- 19. Another component of his hypothesis depends on data from previous independent studies showing that aerobic Mycobacterium Tuberculosis limits the growth of anaerobic species Prevotella. Sandeep‘s hypothesis says this might be one of the main reasons for India’s apparent low numbers of severe cases/ deaths due to COVID19 in India - his exclusive interview with Dental Tribune South Asia. 1. Hi your hypothesis on Mycobacterium TB and Prevotella has generated massive interest and discussion on social media. How did you come up with this theory? How did it all start? Sandeep, Well, a little bit of history. It was late Jan 2020, and I was on the lookout for sequencing data from COVID 19 patients. This is where I pick up all my sequencing data from https://www.ncbi.nlm.nih. gov/sra/ While analyzing from China the the [1] first paper to SARS-CoV-2 report genome I noticed a complete predominance of Prevotella (this was BALF sample). At least in this patient, this was a serious secondary infection [2]. (BALF - Bronchoalveolar lavage fluid) A few days later, I realized the Chinese paper had also noted this abundance in the Supplementary Tables, but made incubation It was already in the back of mind, that tuberculosis might play a role - either positive or negative -in India. However, after the lockdown - and the passing of the average 2 weeks of for symptoms - when I saw that the numbers were low, and the hospitals were not really filling up, I started looking for papers on tuberculosis and Prevotella. That‘s when I stumbled on this hypothesis. required 2. So what is your hypothesis exactly? Metagenomic data of Covid19 patients from across the globe shows a certain distinct pattern- anaerobic bacteria (Prevotella primarily) seem to predominate, ie there is a disruption of balance (homeostasis) with aerobic counterparts. This does not happen in healthy patients. Other independent studies have shown that Mycobacterium Tuberculosis (aerobic bacteria) limits the growth of Prevotella. My hypothesis links these two facts - to postulate that this may be a reason for India’s low COVID-19 severe cases/ deaths. Note, that this does not speak about infections - but the observed limited effect of these infections till date. 3. So that means, the role of Prevotella is very significant in the pathogenesis of COVID- 19. It also brings us to another important point - Prevotella is not new to us, so there must be some published reports on other systemic infections caused by Prevotella. Is there any medical condition that has COVID manifestations but known to be associated with Prevotella? Yes, there is a condition - Lemierre’s syndrome. Many CVID 19 symptoms - especially the serious ones like ARDS, blood clots and septic shock - are also found in a rare ”forgotten” disease, Lemierre syndrome, but with one key - and important - difference: Lemierre syndrome originates the jugular vein, whereas Covid19 emanates from the lungs (which makes treatment much easier). In Lemierre’s syndrome, anaerobic bacteria (mostly Fusobacterium, in This scanning electron microscope image shows SARS-CoV-2 (round blue objects) emerging from the surface of cells cultured in the lab. SARS-CoV-2, also known as 2019-nCoV, is the virus that causes COVID-19. The virus shown was isolated from a patient in the U.S. Credit: NIAID-RML (https://www.flickr.com/photos/nihgov/49565158953) but also Prevotella) colonize the jugular vein (happens mostly in children and young adults) through the peritonsillar blood vessels. Here, forms a abscesses thrombus (blood clot) in which resides the bacteria, which can dislodge and travel through the bloodstream to other organs. They can then form septic infarctions (obstruction of the blood supply). Organs like the lungs, liver, spleen, kidneys and nervous system are thus effected. Please go through these scientific references [1, 2]. and Another interesting similitude is the key role of viruses - just as I postulate that SARS-COV 2 enables anaerobic bacteria, it is known that Epstein Barr virus (EBV) enables LS [3]. Thus, co-infection of SARS-Cov2 and EBV is a distinct possibility, already observed few patients [4]. in a 4. There are some reports of Disseminated Intravascular Coagulation in COVID cases. Any association with Prevotella? observed (blood clot) As mentioned above, the thrombus is a key step in the genesis of the serious form of the disease. And Prevotella (also Fusobacterium and other bacteria) have the required enzymes to do this - specifically, hemolysins which break down red blood cells, and heme-binding proteins which can sequester the heme (which binds iron, which binds oxygen). This leads to the breathlessness observed in almost all COVID 19 patients. And once again, this is not a hypothesis - sequencing data from Covid19 patients show that these proteins are being expressed. Finally, deep sequencing of 3 blood samples did not yield any virus in a Chinese study (where the BALF had significant viral load) [5]. Thus, the theory that the virus attacks haemoglobin chain does not appear to be true. Again, this adds credence to the bacterial hypothesis - something is definitely breaking down haemoglobin, causing clots. 5. Do you have any medical research or microbiology/ virology background to come up with this? Your profile says you have done both - B-Tech and Masters from IIT- KGP. No, I don‘t have a medical degree. I am self-taught in this aspect and can converse with a doctor reasonably well. 6. What components of this theory are already established pieces of evidence and what has yet to be established? Well, I have established that SARS-CoV-2 enables Prevotella to colonize the lungs (it‘s yet to be peer-reviewed, but you have to take my word for it now). The other half of the theory - i.e. MTB doesn‘t allow Prevotella to flourish has been established. A study notes that `MTB+ patients were enriched with Anoxybacillus, recent to with while MTB- patients were enriched Prevotella, Alloprevotella, Veillonella, and Gemella‘ [3]. This observation is reiterated in another study - `yet in pulmonary tuberculosis, contrary the expectation, Prevotella species are decreased rather [4], which goes ahead to propose a mechanism to this resistance - MTB exopolyphosphatase. In short, maybe MTB does not allow anaerobic bacteria to break the homeostasis in their favour. increased‘ than 7. How does your theory connect with Azithromycin - an antibiotic that has generated considerable interest? Azithromycin fits in with the anaerobe colonization theory as an antibiotic. Assuming most MTB is resistant to Azithromycin, I would like to think it will help. But I think there are better Antibiotics for the anaerobic bacteria. 8. How does this whole M. tuberculosis thing connect with the BCG vaccine? And is this the reason why BCG vaccination is being tried as an option to COVID19? There are theories that the BCG vaccine provided innate immune memory [5]. It does have some legs. 9. Does someone need to have active M. tuberculosis in the body to prevent Prevotella?