Original title: Antibiotic cocktails to fight infections resistant to drugs

When they have been on the market for several years, even the most potent antibiotics do not quite pack the punch they did when they were developed.

This is because bacteria mutate and develop resistance to these drugs, making them tougher to kill.

A team of pharmacists at Singapore General Hospital (SGH) is trying to overcome this problem by creating cocktails made up of “older” antibiotics.

These older drugs may not be effective when used in isolation. But when combined with other drugs, they can help to cure drug-resistant infections.

“Bacteria are small and can change very fast,” said Associate Professor Andrea Kwa, a pharmacy clinician-scientist at SGH. “They can multiply every 20 minutes. They are much more efficient creatures.”

Mutations can surface within days, and resistance to new antibiotics can emerge within years.

This is why there are so few new drugs in the pipeline, according to Dr Kwa, who explained: “When something new comes out, bacteria becomes resistant to it in two years, so it’s not profitable for companies.”

As part of a study, Dr Kwa’s team looked at data from 300 patients with serious drug-resistant infections between 2009 and 2014.

One group had received one of more than 100 drug combinations that had been concocted in-house from 12 antibiotics and tested to identify the most effective mix.

Another received individual antibiotics, while a third group was treated with drug combinations that had been used in studies conducted overseas.

The researchers found that 13 per cent of people treated with the inhouse drug combinations eventually died from their infections.

However, the figure was double for the other two methods used.

The team presented its findings at a conference last year, and is now working on a speedier way of identifying the most effective combination of antibiotics.

In Parliament last week, Senior Minister of State for Health Lam Pin Min spoke about the need to tackle the problem of drug-resistant micro-organisms.

The issue has been worsened by the “overuse of antimicrobials such as antibiotics in the human, animal and agricultural sectors”, Dr Lam said.

A national plan on antimicrobial resistance was launched last November. As a general rule, choosing the right method of killing bacteria is very important.

Describing SGH’s current tactics as a “hit and run”, Dr Kwa said: “You need to give the correct doses that totally kill the bacteria in a few days, so that it has no chance to stay dormant and mutate.”

Meanwhile, the National University Hospital (NUH) tries to use the most targeted methods possible to kill bacteria, said Dr Natasha Bagdasarian, a consultant with the hospital’s division of infectious diseases.

“It’s always better to target a narrow spectrum of bacteria when we can,” she said. “Fewer bacteria are targeted, so fewer bacteria are ramping up their defence mechanisms.”

New methods include finding ways to stop the disease without killing the bacteria, using viruses that target bacteria without harming humans, and stimulating a person’s immune system to do the job.

Senior research scientist Swaine Chen, from the Genome Institute of Singapore’s infectious diseases group, said: “These new strategies are largely in the research and development stage, which is why services like (SGH’s) serve an important role today.”