Researchers believe that fungi - such as the 10 different Penicillium species shown here (each grown on two different media) - harbor a vast potential source of new antibiotics to fight infectious diseases.
Image credit: Chalmers University of Technology
The researchers report their findings in a paper published in the journal Nature Microbiology.
Antibiotics are drugs that treat and prevent bacterial infections - either by killing the bacteria or by stopping their spread. Antibiotic resistance arises when the bacteria change after being exposed to these compounds.
Since the 1940s, antibiotics and other antimicrobial drugs have dramatically reduced illnesses and deaths from infections caused by microbes.
However, due to the prolonged and widespread use of these drugs, the bacteria and other disease-causing microbes that the medicines are designed to kill have evolved the ability to survive them.
According to the Centers for Disease Control and Prevention (CDC), at least 2 million people contract antibiotic-resistant infections and more than 23,000 people die from them in the United States every year.
The illnesses caused by antibiotic-resistant bacteria - which can infect animals as well as humans - are becoming much harder to treat than those caused by non-resistant bacteria.
Fungi less well-understood than bacteria
- Antibiotic-resistant infections require longer stays in hospital, cost more to treat, and carry a higher risk of death.
- Antibiotic resistance is one of the most significant threats to public health, food security, and the world's development.
- It can affect anyone, no matter how old they are or where they live.
The World Health Organization (WHO) have warned that unless the situation is addressed urgently, the world is "heading for a post-antibiotic era, in which common infections and minor injuries can once again kill."
Nature is an obvious place to look for compounds with antibiotic properties. Microorganisms produce compounds that attack other species of microorganisms to help them survive in a competitive environment.
However, the researchers behind the new study note that attempts to find new antibiotics in nature have mainly focused on bacteria because they are much easier to study than fungi, about which we understand much less.
However, they note that fungi (much like bacteria) also make bioactive compounds - molecules that have an effect on living cells - to defend against competitors.
The team therefore decided to use the genome-sequencing tools that have been used to investigate bacteria to analyze fungi and their potential for producing bioactive compounds.
More than 1,000 pathways for bioactive compounds
The data from these sequences, and those obtained from the sequences of 15 published genomes, yielded what the authors describe as "an immense, unexploited potential" for producing bioactive compounds in this genus.
From the genome sequencing data of 24 different species of Penicillium, the team identified more than 1,000 pathways - patterns of particular molecular reactions and events - for producing a variety of bioactive compounds with medicinal potential.
The researchers were able to predict the compounds produced by 90 of the pathways - including those that produce a class of antibiotics called yanuthones.
Upon further investigation, they found a formerly undescribed yanuthone produced by a species of Penicillium that was previously not known to make yanuthones.
Thus, the authors believe that their findings show not only that fungi may offer a vast potential source of new antibiotics, but also that they unlock a source of new - and perhaps more effective - versions of old drugs. They conclude that:
"This study is the first genus-wide analysis of the genomic diversity of Penicillia and highlights the potential of these species as a source of new antibiotics and other pharmaceuticals."