A study conducted in March 2021 by the Vallabhbhai Patel Chest Institute, Delhi, in collaboration with the Department of Ocean Studies and Marine Biology, Pondicherry University, has for the first time found a deadly hospital pathogen, known as, the Candida auris, or C. auris in the environment, off the coast of South Andaman district in the Andaman and Nicobar islands. Prior to this, fungal pathogen C. auris was not known to exist outside the hospital environment.
For this study, samples were collected from the coastal wetlands, including rocky shores, sandy beaches, tidal marshes, and mangrove swamps around the Andaman group of islands union territory of India. Total 48 samples of sediment soil and seawater were collected from eight sampling sites across the east and west coast of South Andaman district. C. auris was isolated from two of the eight sampling sites—a salt marsh and a sandy beach. Two colonies of the C. auris were found at the salt marsh from the composite soil sediment and 22 colonies at the beach. The water sample contained both multidrug-susceptible and multidrug-resistant isolates. Its survival in marine habitat confirms that the infected fungus can live in both marine and terrestrial areas.
Superbugs are strains of bacteria, viruses, parasites, and fungi that are resistant to most of the antibiotics and other medications commonly used to treat the infections they cause. According to the US Centers for Disease Control and Prevention, Candida auris is a multidrug-resistant pathogen (fungus) that presents a serious global threat to human health. Candida aurisbelongs to the Candidahaemulonii complex of the Metschnikowiaceae clade of the order Saccharomycetales. The related species of the Metschnikowiaceae family have been detected in plants, insects, and aquatic environments, as well as from human body sites.
As per the study, the closest known relative of C. auris is C. haemulonii, which was first discovered in 1962 from the gut of Haemulonsciurus (a blue-striped grunt fish). It was also found in the skin of dolphins, and the seawater off the coast of Portugal. Unlike the related species, C. auris has not been reported from natural environments. These retrospective analyses of clinical yeasts showed that the earliest known clinical isolates of C. auris date back to 1996 in South Korea and 1997 in Japan. However, unlike the clinical settings, the detection of C. auris in the natural environment has not been explored.
Fungi predominately thrive in tropical and subtropical areas like the Andaman islands. As fungi are present in the environment as degraders of organic matter, detection of C. auris in the marine habitat of Andamans is not a matter of surprise.
- auris was identified for the first time in 2009 in an infected patient in Japan. In the last 10 years or so, C. auris has spread across more than 40 countries in five continents. Due to it being an emerging pathogen not much is known about it. According to some experts, the transmission pathway of the fungus from the environment to patients in hospitals is yet to be established and needs to be explored, though it can enter the body through invasive procedures or even devices, such as catheters. But now it is known that the drug-susceptible fungus that can be treated with medication might adapt inside the human body and become drug resistant. This makes the pathogen quite difficult to treat.
The C. auris can be fatal for immunocompromised (weakened immune system) persons. Incidence of casualty from fungal infection has been found to be higher in countries like the US and the UK, its prevalence is less in Indian hospitals. But as per the research studies, presence of the fungal infection has been found in patients in ICUs across our country. The fungus becomes deadly when it gets into the bloodstream or inhabits the body of a cancer patient, etc. According to some studies, mortality in 30–60 per cent patients, who were already critically ill and admitted in ICUs, occurred due to C. auris infection.
An earlier theory about C. auris established that the fungus might be native to wetlands and its emergence as a human pathogen might have been linked to global warming effects on wetlands, and it flourished in that environment due to its ability of thermal tolerance and salinity tolerance.
It makes the human body more susceptible as a host for the bugs since most other fungi cannot flourish due to the high temperatures inside the human body. Growing infections across the globe in healthcare facilities have been attributed to the unique characteristics of this superbug to survive and persist within the hospital environment for prolonged periods. Its ability to survive on dry environmental surfaces for long time periods suggests that C. auris is well adapted to survival outside human host settings.
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