Last week, drug company CSL wrote to hospitals, advising them to start rationing an intravenous form of penicillin, known as benzylpenicillin, or BenPen. With supply limited until December, there are concerns about “superbugs” sweeping Australia’s hospitals.

But what exactly is a superbug, and how does penicillin combat this microbial menace? To find out, Crikey spoke with Peter Collignon, an infectious diseases physician and microbiologist at the Australian National University.

What is a “superbug”?

“A superbug is bacteria that doesn’t respond to standard antibiotics. It’s a bit analogous to putting on a Superman suit — all of our bullets bounce off it,” explained Collignon. The most well-known examples of bacteria resistant to antibiotics are golden staph (Staphylococcus aureus) and E. coli (Escherichia coli).

Golden staph is one of the most common causes of septicaemia in Australia. “If we ever got to the stage where we didn’t have antibiotics to treat it, that would be a major problem,” said Collignon.

Why is it a health risk?

A 2011 paper from the Australian Commission on Safety and Quality in Healthcare reports patients with antimicrobial-resistant infections are more likely to “experience ineffective treatment, recurrent infection, delayed recovery or even death.” The death rate for people with these sorts of infections could be as much as two-fold higher. “Basically if you get a serious infection with them you die more often and spend more time in hospital,” explained Collignon.

What creates superbugs?

Superbugs can be cultivated by the indiscriminate use of broad spectrum antibiotics. An April 2011 article in leading medical journal The Lancet argued “from the moment antibiotics were discovered, they have been used excessively and with little attention to the inevitable consequence of resistance.” Antibiotics use can help resistant bacteria grow and spread not only in hospitals, but also in the community at large and in long-term care facilities.

Why is penicillin so important?

Narrow spectrum antibiotics are needed to fight off infections without increasing the likelihood of antibiotic resistance. Collignon says penicillin is “one of the narrowest” forms available. Benzylpenicillin, or BenPen, is even more important because “it’s an example of the only penicillin available that you can use intravenously to treat infections.”

Why is the rationing of BenPen such a big deal?

“For a country like Australia to find it can only get limited supply is astounding,” said Collignon. As a developed nation, we have both the experience and expertise to manufacture this drug, which plays a vital role in the fight against infectious diseases.

One possible downside of the rationing of BenPen is the increased use of broad spectrum antibiotics, which could further increase the likelihood of superbugs in hospitals and the community. “I think it’s unbelievable that a basic drug like penicillin is not going to be available or is to be rationed for a few months,” said Collignon.