"The fact that unrelated NDM-1 producing bacteria have been found in a patient in a public sector hospital would indicate that, if we look harder, this problem is more widespread than we think," said Professor Adrian Duse.

Duse, the head of the outbreak response unit of the National Institute for Communicable Diseases, was responding to questions about a recent outbreak of the superbug.

Ten patients at the Life Glynnwood Hospital had been diagnosed with NDM-1 and another at Charlotte Maxeke Johannesburg Academic Hospital.

"Early detection by screening patients means that [Life Glynnwood Hospital], because of its proactive screening programme, was more likely to find NDM-1 carrying patients than in other healthcare facilities where screening might have been less intensive," Duse said.

NDM-1 is an enzyme produced by bacteria, making bacteria resistant to antibiotics.

On Saturday, a fourth patient infected with the enzyme died at the Glynnwood hospital. It could not be determined to what extent NDM-1 had contributed to the four deaths, as each of these patients were seriously ill with other medical conditions.

"Healthy people, the general public, typically don’t get sick from NDM-1 producing bacteria," Duse said.

Those with underlying medical conditions were more likely to become ill from NDM-1 producing bacteria.

"The symptoms depend on the body site where these organisms are found.... If the organisms for example infect the lungs you would see the symptoms of pneumonia (like any other bacterium causing a lung infection) and so on," he said.

Some people might carry NDM-1, but experience no symptoms whatsoever.

The Life Glynnwood Hospital had strict precautions in place to prevent the spread of the superbug to its patients and staff.

As it is not typically airborne -- like influenza, for example --separate ventilation systems and masks were not necessary to contain NDM-1, Duse explained.

Staff wore gloves and aprons to prevent the spread to other areas of the hospital, and the two remaining NDM-1 patients were kept in isolation wards.

Standard hospital cleaning and disinfection procedures were adequate to dealing with the superbug, he said.

NDM-1 was first identified in New Delhi, India. Due to global travel, it has been detected in patients in public and private facilities around the world. It is named a "superbug" due to its resistance to antibiotics.