Friday, August 23, 2019

Candida auris: A new fungus among us


Fungi, like bacteria, surround us.

These organisms — which include yeast and mushrooms —come in many forms, including Candida species, a fungus that is common and ubiquitous. Candida albicans, for example, is the causative agent of thrush, vaginal yeast and other skin infections, and can be easily treated. However, this is not true of a “new” fungus on the block, Candida auris.

A highly magnified view of Candida auris.
“Auris” means ear in Latin and is an appropriate name for this organism, which was discovered in the ear of a Japanese woman in 2009. Considered an oddity at the time, Candida auris quickly spread around the world, appearing a year earlier in Pakistan (2008), then subsequently in India (2009), Venezuela (2012), the United States and South Africa (2013), and Europe and Australia (2015).

Candida auris actually exists in at least four distinct genetic variants, leading researchers to believe that it has arisen independently in several different locations around the world.

Candida auris, a relatively new fungus, is a highly efficient killer.

Candida auris is not, however, just another fungus. It has proven to be highly resistant to many antifungal drugs. It spreads rapidly through hospitals, nursing homes and long-term care facilities where it proves difficult, if not almost impossible to eradicate. More common in weakened and susceptible patients, it kills nearly half of those infected within 90 days
Evolution and control

Where did this horror come from (besides from the ear of a Japanese woman) and what can be done to control or eliminate it?

Fungal specialists believe that our widespread use of antifungal agents has gradually resulted in the evolution of this previously harmless fungus. Much like the widespread use of antibiotics has caused the evolution of multiple drug-resistant bacteria, antifungal agents have created an environment favorable to the development of fungi that are immune to most antibiotics.

With antifungal agents so widely used in agriculture, resistant fungi will reproduce and flourish. It is not exactly survival of the fittest, but more precisely survival of the most adaptable. Candida auris appears to be one of these highly adaptable organisms.

We cannot easily produce new antifungal agents, nor can we eliminate the use of fungicides (or antibiotics) for agricultural purposes. It may come down to the same principle of highly selective use which has already been applied to antibiotics. Fungicides can be restricted or outlawed, even though the consequences on agricultural production may be dramatic.

For example, the fungus that destroyed the potato harvests in Ireland in the 1840s led to widespread crop failures, disease and famine. The same could occur with a new resistant fungus in our time that could wipe out wheat or rice harvests. Possible reductions in agricultural productivity must be weighed against the dangers posed by these new organisms.
Source: CDC

What comes next?

We can restrict our use of both antifungal and antibiotic agents to circumstances when they are truly required. Hospital infectious disease practitioners must add Candida auris to their already long list of resistant organisms they need to identify, track and eliminate in the hospital, long-term care and nursing home settings.

We are all engaged in this intense battle between humankind and the world's microorganisms, whether they be fungal or bacterial. Common sense must prevail or we will become victims of these horrific microscopic organisms that may kill with impunity because there is nothing available to use against them.

Learn more about Candida auris here.

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