Antibiotic-resistant superbug numbers 'have been rising' - microbiologist

News 21/12/2018
Photo: Getty.

There have been twice as many cases of antibiotic resistant superbugs detected in New Zealand this year than in 2017, a prominent microbiologist says.

Last year there were 34; with the addition of this week's cases at Middlemore Hospital there have now been 70 in 2018, Siouxsie Wiles told RadioLIVE on Friday.

"This is an organism we don't see here very often, but numbers have been rising... There have been cases overseas where there have been no antibiotics and the patient died - that's what we're trying to avoid here."

Bacteria have been getting increasingly resistant to medicine in recent years, thanks to evolution and aided by our widespread use of antibiotics.

It works like this: when an antibiotic fails to wipe out a colony of bacteria, it's because the survivors have mutated in a way that protects them. The survivors pass on the mutation, so the new colony they form will be stronger than the last against that particular antibiotic. They can also pass on their mutant genes to other bacteria, spreading the resistance.

Some bacteria are now at the point where no traditional antibiotics work - these are the kind found in two patients who were recently at Middlemore.

"In this particular case we've got what we call the 'last resort' antibiotics, which are not very nice antibiotics at all," said Dr Wiles.

"But there are strains of these bacteria overseas that are also resistant to those."

The jump in detections here could be because they are growing in numbers, or that more screening is being done.

"It could be both," said Dr Wiles, noting that some of us could be carrying the bugs without any ill-effects - for now.

"People can carry them in their guts with no effect, but if it gets into the bloodstream of someone who's very ill, it can be very, very dangerous because there are very few antibiotics left to treat this bacteria.

"And so when people go into hospital and more people are being screened to see if they are carrying this bacteria, obviously if it transmits between patients, there's much more chance it could cause somebody serious harm."

Earlier this year Dr Wiles told Newshub a decade ago there were only about six cases of antibiotic-resistant superbugs a year in New Zealand. Luckily, so far none of the cases here have proven fatal.

It can take years to get new treatments out of the lab and into pharmacies, but Dr Wiles says there's a simple way to lessen the risk in the meantime.

"Being really careful about washing hands after being to the toilet, washing hands before doing anything - hand hygiene is the best defence against these organisms, because we don't have any vaccines against them."