SARS-CoV-2 is now well adapted for human to human transmission, leading to Covid-19, as named by WHO with pathogenic consequences of severe pneumonia in all severe cases.
By Suman Kapur
COVID-19: What became known as Covid-19 started in late 2019 as a cluster of pneumonia cases with an unknown cause. The cause of the pneumonia was found to be a new virus – Severe Acute Respiratory Syndrome Coronavirus 2, or SARS-CoV-2. The novel coronavirus (SARS-CoV- 2) belongs to the family of Coronaviridae and genus betacoronavirus, comprising vertebrate respiratory viruses including HCoV-OC43, responsible for 10% cases of common cold.
SARS-CoV-2 is now well adapted for human to human transmission, leading to Covid-19, as named by WHO with pathogenic consequences of severe pneumonia in all severe cases. Pneumonia is an infection of lungs caused by bacteria, viruses or fungi. People with Covid-19 develop a cough and fever when the infection reaches the respiratory tree – the air passages that conduct air between the lungs and the outside. When the alveoli, the gas exchange units in our lungs, at the end of the air passages, become infected they respond by pouring out inflammatory material into these air sacs leading to a condition in which the air sacs fill with pus and other liquid.
Patients with viral pneumonia, as is the case post Covid-19 infection, are at an enhanced risk of developing secondary infections requiring treatment with antibiotics. This draws our attention to a larger threat trailing the current Covid-19 associated severe pneumonia-one that is already killing a large number of people around the world and which could further complicate the care of many Covid-19 patients.
Also read| Check latest updates here:
This is the looming threat from Antibiotic Resistance Bacteria (ARB) that are not killed by standard antibiotics. Unfortunately, the pipeline of drugs to manage these deadly infections is nearly dry. Situation in many countries including India is grim due to the growing number of ARB.
Aquatic environments harbour diverse bacterial communities. The surface and groundwater used for drinking/recreational purposes have been reported to contain 17% E. coli, resistant to cephalosporin, in central India, 07 % in Kashmir, 50% in Sikkim and 100% in Hyderabad and parts of Karnataka.
Presence of antibiotics in river water is a global concern and Yellow, Hai and Liao River in northern China have been reported to be contaminated with numerous antibiotic residues like Ciprofloxacin, Norfloxacin, Oxytetracycline and Ofloxacin. A study led by University of York estimated the presence of 14 antibiotics in rivers of 72 countries across 6 continents. The authors reported that 65% of the total of 711 sites tested positive for presence of antibiotics with some of them at concentrations up to 200 times of the safe-level range (as per antimicrobial resistance, ‘AMR’, industry alliance standards). Ciprofloxacin most frequently exceeded safe levels, surpassing the safety threshold at 51 places with high-risk sites being adjacent to wastewater treatment systems and waste/sewage dumps. According to the investigators safe-limits were frequently exceeded in Asia and Africa, but sites in Europe, North America and South America also had high levels emphasizing the important role of the natural environment in the AMR problem.
Rivers in India are no exception as antibiotics and Active Pharmaceutical Ingredients (APIs), have been found to be present in Musi in Telangana, Kaveri, Vellar and Tamiraparan in Karnataka, Shipra in Madhya Pradesh, Sabarmati in Gujarat and Ganges in Uttar Pradesh. Additionally, all these rivers have been found to have Multi Drug Resistant (MDR) and Extensively Drug Resistant (XDR) bacteria. These environments allow them to function as ‘hotspots’ for resistance through selection of ARB and the circulation of Antibiotic Resistance Genes (ARGs) through the stimulation of horizontal gene transfer between members of the microbiome/s. The high cost of regular monitoring of ARBs makes it a low-priority and this potentially ‘AMR-rich’ wastewater is finally discharged into the nearest water bodies.
MDR bacteria, called “Super-bugs”, pose a great threat to human health as infections caused by them are difficult to treat and lead to high mortality. A study published by the ICMR found ARB in the gut of 67% healthy persons, pointing to a rapid spread of AMR in Indians. Our study of pathogens isolated from Musi river in Hyderabad showed MDR (resistance to 2 or more) against frontline antibiotics. Of the 292 isolates tested for sensitivity to 14 antibiotics 24% were resistant to Carbapenems; 30% to broad spectrum antibiotics for gram-negative bacteria; 31% to 2nd generation fluoroquinolones, 47-61% % resistant to broad and narrow spectrum antibiotics for gram-positive bacteria, 77% to beta-lactam class, 50-88% to 1st to 3rd generation cephalosporins.
Now, in patients suffering from Covid-19, if the secondary infection is caused by ARB then the situation becomes harder. The first-line of antibiotics used in pneumonia are broad-spectrum macrolides such as azithromycin and we found 30-50% resistance to Azithromycin. Growing AMR is a global phenomenon making treatment of pneumonia harder only with last resort, namely respiratory support using respirators/ventilators in hospitals claiming an enormous toll on healthcare systems worldwide.
The columnist is Senior Professor, Birla Institute of Technology and Science, BITS Pilani. Views expressed are the author’s own.