Professor Lakshman ‘Sam’ Samaranayake is the world authority on oral Candida, having made it his career mission for the past 40 years. He explains why this is one disease you should never take your eyes off. Report by John Burfitt
As a young dentist, Professor Lakshman ‘Sam’ Samaranayake took on post-graduate studies in Glasgow in 1977 and oral Candida soon became his fascination.
Having grown up in Colombo, Sri Lanka, it was a health issue Professor Samaranayake had barely been exposed to previously. Scotland in the late 1970s, however, was a very different story. So widespread was the condition, he soon decided to devote his studies to understanding the complexities of oral Candida. That decision would change his life and career to such an extent that today, Prof Samaranayake is held as the world authority on oral Candida.
“I was working as an oral microbiologist in the Glasgow Dental Hospital, and what constantly surprised me was the number of swabs that kept coming up with positive results for Candida,” says Prof Samaranayake. “This was something I had just never seen in Sri Lanka.
“In Scotland, there was such a high prevalence of it. There was this notion at the time that if you had all your teeth extracted, you would never get heart disease. So, we had many old men and women coming in with rather unhygeinic full dentures, teeming with Candida-laden plaque. I was fascinated and that was when I began to be really interested in investigating what it was all about.”
Almost 40 years on, Prof Samaranayake’s fascination with oral Candida shows no signs of waning. If anything, at age 66, there are new areas of investigation into the condition he now wants to explore.
Any future study will be in addition to his work that has brought him acclaim, including authoring over 400 research articles, the IADR Distinguished Scientist Award in Oral Medicine and Pathology, as well as the King James IV Professorship from the Royal College of Surgeons of Edinburgh.
As of January last year, Prof Samaranayake’s relocated to Brisbane to take on the role as the head of school and the professor of oral microbiomics and infection at the School Of Dentistry at the University of Queensland. He has been hard at work guiding the studies of dental students ever since.
“We discovered a world of fascinating new details about it and the other ways it could show up in the mouth.” Professor Lakshman Samaranayake
As Prof Samaranayake’s career has travelled such a clear path into microbiology and unlocking the secrets of oral Candida since those days in Scotland, it comes as something of a surprise when he admits he had a fundamental dilemma about specialising in the condition in the first place. If he had listened to some critics, he could just have easily turned his back on oral Candida a long time ago.
In one corner was his mentor, Professor Wallace MacFarlance, who recognised the young student’s keen fascination that he wanted to foster and encouraged him to sit for the membership exam of the Royal College of Pathologists in Microbiology, at the same time he was completing his doctorate of dentistry.
In the other corner were Prof Samaranayake’s peers who regularly questioned why he would be wasting his time on a health issue that was, as was considered at the time, no longer relevant.
“I still remember many colleagues saying to me, ‘Sam, why are you studying this dead disease? Candida is so easily cured now. There is nothing more to it’,” he recalls.
“Only a matter of years later, the HIV epidemic came along and then Candida became a very important issue all over again. We discovered a world of fascinating new details about it and the other ways it could show up in the mouth.”
HIV changed not only the way oral Candida presented, but how it was studied. “Candida infections were once just white patches. Then with HIV, they showed up as red patches as well. That took me on a completely new trajectory, looking into the causes of this disease, particularly in immune-compromised patients in general.
“We then began to understand that oral Candida was a disease of the diseased. People who contracted HIV presented with oral Candida as one of the first signs of the underlying fatal disease. If you diagnose the disease early, then you can help them as well as their partners by preventing the further spread of HIV.”
In those days, as new treatments for oral Candida were being trialled and often experimental, adaptations were often made in a valiant effort to solve the problem.
“As general vaginal infections were more common than oral Candida, I can still remember giving people vaginal treatments to be used in the mouth,” he says. “They were so bitter but they were effective and did work. We have improved so much since then with far better drugs like Fluconazole.”
Since those days which had such an influence on his career direction, Prof Samaranayake has worked all over the world, having lectured on the topic of oral Candida and other infectious diseases and their prevention on five continents.
Prior to moving to Brisbane, he spent 10 years as the dean and chair of oral microbiology at the Faculty of Dentistry and Tam Wah-Ching Professor of Dental Sciences at the University of Hong Kong. He also acted at the same time as the director of the Prince Philip Dental Hospital.
He has previously held teaching and consultant positions at the University of Glasgow, University of Alberta in Canada and the University of Peradeniya in Sri Lanka. He has also served as a director of the FDI World Dental Federation and the chair of its Science Commission.
Prof Samaranayake remains on a mission with his current work at the University of Queensland, intent that students do not overlook the importance of identifying the true implications of oral Candida infections.
“Some types of Candida infections should never be overlooked as it may turn out to be a primary indicator of a whole range of other things in the body that are not going so well,” Prof Samaranayake says.
“It could eventually turn out to be a cancer of the oral cavity. There is still a lot unknown about Candida infections and we have to look at that, like how it invades tissues, what it does inside the oral cavities and how it interacts with other organisms.
“One in two of us have yeast in the mouth, and under normal conditions, they live there happily. But for some people, it begins causing disease and that is when we need to look at what it is doing. In some situations if Candida infections are neglected and not treated, about 15 per cent of cases can turn out to be malignant. It should not be easily dismissed.”
“There are not too many specialists in this area in Australia and specialisation in general is not as strong as it once was.” Professor Samaranayake
As for the overall state of oral health in Australia, Prof Samaranayake says he is impressed with what he has seen since arriving, and believes it is an improvement from some other countries he has lived in.
But it is the state of oral health in outback Indigenous communities that Prof Samaranayake now wants to examine. He hopes to launch a new study into the presence and behaviour of oral Candida and related infections in those communities.
“I am concerned about some of the news and what I have heard about the dental care in some in the more remote communities,” he says.
“I am just curious about the prevalence of Candida within Aboriginal communities as an area awaiting exploration and I plan to look at it in time to come as the disease can show up in a range of different ways.
“For instance, in some population groups in Scandinavia, Candida infections appear as chronic incurable infections of the mouth, the skin and the nails. Such conditions are always worth following as they provide clues to the strange behaviour of this ubiquitous yeast.”
The other area that remains high on his agenda is the state of funding for dental studies in higher education institutions across Australia.
He is worried what the current changes in university funding could mean to the long-term quality of dental services being provided. “It’s no secret that all the dental schools here are going through a rough patch and funding is very tough right now,” says Prof Samaranayake. “I feel strongly that so many post-graduate programs are dying. There are not too many specialists in this area in Australia and specialisation in general is not as strong as it once was. That is something we need to keep an eye on as we need specialists to keep our industry strong into the future.”
His textbook, Essential Microbiology for Dentistry, has been translated into four languages and is now in its fourth edition. It stands as the definitive statement of Prof Samaranayake’s career study into oral Candida and infectious diseases. He calls the tome the “legacy of my career—something that still stands and remains as a flag to remind people of the importance of this area of study”.
And besides, even though he is the world leader in oral Candida and the man everyone turns to when they have questions, he still has questions that need answering. Even after 40 years of dedication, Prof Samaranayake admits he has one question that remains unanswered.
“The only thing about Candida that stumps me is why does it become pathogenic and what is its tipping point?” he asks. “It is the host, and systemic factors that drive the yeast to become a parasite—I believe it is the best answer I can give,” says the professor.
“So at this stage, retirement is not an option for me, as I feel I still have more work to do. When that is complete, then maybe I will slow down then. However, that is a long way off.”