Fungi join fight against infection

Dr Bevan Weir collects another fungi specimen near Glenorchy, Queenstown.

A collection of New Zealand fungi could play a vital role in solving one of the world’s most serious health concerns.

Microbes have evolved to become resistant to known drugs, including antibiotics. The importance of this cannot be overstated. A report commissioned by former British Prime Minister David Cameron concluded this resistance could lead to 300 million premature deaths by 2050 and cost the global economy up to £64 trillion.

Not surprisingly, scientists are searching the world for solutions, and here in New Zealand Landcare Research is playing a leading role. Researchers are methodically trawling through the Crown Research Institute’s collection of about 10,000 fungi specimens looking for any medicinal properties that could fight infections. New Zealand scientists have been collecting fungi for a century, and Landcare Research is the current custodian of the fruits of their labours.

Dr Bevan Weir believes a solution could be ‘waiting to be discovered’ in one of the specimens. "What we hope to discover are novel antibiotics with completely new chemistries, new molecules or classes of molecules that have not been seen or discovered before," he said. "There are whole classes of drugs out there, beta-lactam antibiotics, all based on the original penicillin structure. The problem is that bacteria can have an enzyme (beta-lactamase) that attacks the key structure of this class of antibiotics. That means it can disable the entire class of antibiotic, so what we are hoping is that there will be an entirely new class in our collection."

The research, in association with Auckland University microbiologist Dr Siouxsie Wiles, is based on more than a scientific hunch. Weir said, "We are working on the assumption here that the fungi of New Zealand are in some way different from what has been screened before. This is not quite as unusual as it might seem. We at Landcare Research and formerly DSIR have been working since 1920 on fungal taxonomy. So far we have described or put a formal name on only one-third of what we think are 22,000 native species. We are isolated, and have been as a set of islands for millions of years. So there is reason to assume there is a high level of endemism in our fungi as in our native plants and insects. They are quite different in New Zealand. So it is reasonable to assume fungi in New Zealand might have evolved different antibiotic strategies to kill bacteria from what has previously been seen elsewhere."

Landcare Research’s fungi collection is stored in liquid nitrogen. Microorganisms are extracted from its dewars, placed on agar plates and grown into individual colonies (each clone or co-culture is genetically identical to the original organism). They’re then sent to Wiles, who adds luminescent bacteria to the fungi. If bacteria are killed by something the fungi produce, the lights go off. This provides a fast and accurate method to assess their suitability for further analysis.

Buried in Landcare Research’s vast collection were about 100 fungi with no name associated with them. Weir screened these first, "Because I had no idea what they were and I was taking a bit of a punt and I think that idea of not applying a bias is kind of important. We are looking for new stuff here, and so if you went down the track of known fungi a lot of antibiotics come from you will probably just rediscover the same things so in some ways it is good not to have a target."

It is early days in the research, but so far testing has yielded promising results worthy of further chemical anlysis. "It is a numbers game. We have 10,000 fungi in the collection. If I bought 10,000 Lotto tickets there’s a pretty good chance I am going to win something and I think that shows in early stage testing. One of the medically important bacterial species seems to be susceptible to aquatic fungi. Another [fungus] was used traditionally by Māori to seal wounds and stop bleeding, and that seems to have broad spectrum antibiotic properties, at least in early testing."

Further research is needed before the research is deemed a success or otherwise. But, as Prime Minister Cameron, noted, "If we fail to act, we are looking at an almost unthinkable scenario where antibiotics no longer work and we are cast back into the dark ages of medicine."

No man would be happier if the solution was found buried in Landcare Research’s collection. Weir said: "Mostly these collections are used for taxonomic, biosecurity and biodiversity studies. One recent example of this was being able to show MPI [Ministry for Primary Industries] that a group of harmful bacteria found oversea had been collected and detected here in 1992 so there was no need for a full biosecurity response. But the collection continues to surprise me in terms of what is hidden in this vault of liquid nitrogen. There are so many things in the collection we have not discovered a use for yet, and that’s what makes the Nationally Significant Collections like ours a little different from the university collections in that they have been built up over many decades .

"There is a perception from some that the collection is a sitting in the corner, but it is very active. We receive 600 requests from around the world each year requesting cultures for research, and similarly several hundred cultures are deposited into the International Collection of Microorganisms from Plants (ICMP) every year as well. The ICMP is an international, publicly available collection of live cultures of fungi and plant-associated bacteria. The Landcare Research collection makes up a valuable part of this resource."

NOTES ON FUNDING: Landcare Research allocated $46,040 of MBIE Core Funding to ICMP Biodiscovery research in 2015/16 [794004-0801]. A total of $764,625 of MBIE Core Funding was allocated to preservation, maintenance and biosecurity research of the New Zealand Fungi and Bacteria collection.