Canadian researchers recognized as key part of global effort to curb spread of gonorrhea

Public health officials around the world are raising the alarm about a dramatic increase in the incidence of gonorrhea—a sexually transmitted infection that causes a significant burden to public health and, if left untreated, can lead to serious and permanent health problems for both men and women.

The number of cases of gonorrhea reported in Canada has been rising steadily over the past 20 years, with close to 6,000 cases reported in Ontario alone in 2015. The actual number could be even higher, since the symptoms of gonorrhea can be very mild and even non-existent. Around the world, it's estimated there are close to 80 million new infections a year.

Resistance to antibiotics is increasing

Once considered little more than a nuisance that could be cleared up with a shot of penicillin, gonorrhea is now a major public health concern. As Public Health Agency of Canada (PHAC) biologist Irene Martin explains, treating the infection is not as simple as it used to be.

"More and more strains of Neisseria gonorrhoeae, the bacteria that causes the disease, are showing resistance to currently used antibiotics," says Ms. Martin. "To keep these drug-resistant strains from becoming established in the population, we need to ensure infected people get the most effective treatment as early as possible."

Until recently, identifying the most appropriate treatment was largely a matter of trial-and-error—growing a culture of the bacteria in the lab, and then testing it with various antibiotics to see which ones worked. As the science of genomics advances, that is changing.

Genomics offers progress, but…

Biologist Walter Demczuk, Ms. Martin's colleague at the PHAC's National Microbiology Laboratory (NML) in Winnipeg, says researchers around the world have been studying the genomes of the bacteria, looking for the genes that indicate resistance to specific antibiotics. "This is a much faster and more accurate way to identify drug resistance, but it's been difficult to put the information to use, because different researchers often refer to the same gene in different ways," says Mr. Demczuk. "In essence, we've been speaking different languages, and that has slowed down the pace of progress."

With the support of funding from the Genomics Research and Development Initiative (GRDI) and working with researchers from the USA, UK, Australia, Sweden and the Netherlands, the team at the NML has created a sort of universal translator for drug resistance in gonorrhea—it's called NG-STAR, which stands for Neisseria gonorrhoeae Sequence Typing for Antimicrobial Resistance.

It's all in the numbers

The NG-STAR website. Long description follows.

The NG-STAR website gives researchers a straightforward, automated tool to check for drug resistance in different strains of gonorrhea bacteria.

Long description

Users enter their allele types in a query to obtain the NG-STAR profile of their isolates.

"We've looked at the DNA of hundreds of isolates of drug-resistant strains of the bacteria, identifying and cataloguing the genes that indicate resistance to particular antibiotics, and then giving each one a number," says Ms. Martin. "We've made the data accessible to everyone, so a researcher on the other side of the world can go to our website, and quickly compare DNA sequences from the strain of gonorrhea they're looking at to the sequences in our database. If their strain includes a match for gene number 20 in our system, for example, NG-STAR will tell them it is likely to be resistant to this or that antibiotic."

Small team, big win

As a mark of the significance of the accomplishment involved, the Sanger Institute has asked the PHAC researchers if it could incorporate NG-STAR into a broader gonorrhea sequencing project underway at Sanger headquarters at Oxford University in the UK.

"The Sanger Institute is one of the biggest and most influential centres for genomics research in the world," says Mr. Demczuk. "It's a huge organization, so to have them reach out to our little team of four or five people, to recognize the value in what we've done—well, it feels pretty good."

"It has been a real team effort, and without people like Dr. Gary van Domselaar (head of bioinformatics at PHAC) and programmer/coder Sukhdeep Sidhu, we would never have been able to do this," says Mr. Demczuk. "Of course, without the funding from the GRDI, we wouldn't have had a project at all, let alone one that will help to address a growing public health concern in Canada and around the world."

Date modified: