Research aims to limit hospital stays

A study by Macquarie University scientists will investigate antibiotic resistance genes in humans in an effort to combat worldwide death rates due to infectious diseases and reduce the growing burden on our health system by decreasing patients' length of stay.

Macquarie University molecular biologist Professor Hatch Stokes and colleagues Dr Ruth Hall and Dr Ian Paulsen will receive National Health and Medical Research Council (NH&MRC) funding totalling in excess of $480,000 over the next three years.

Antibiotics are generally regarded as one of the greatest discoveries of the twentieth century and, after they first came into widespread use, doctors were confidently predicting that 'the book will be closed on infectious disease'. Today, antibiotic resistance genes are in 'plague' proportions, the result being a re-emergence of traditional bacterial diseases such as cholera as well as an increase in hospital-acquired infections such as Golden Staph (Staphylococcus Aureus), in developed countries resulting in a high number of deaths each year, as well as increased hospital length of stay.

Stokes and Hall are best known for their discovery of the mobile genetic element which they named the 'integron'. Due to their ability to acquire and rearrange genes, integrons are a major contributor to the rapid spread of antibiotic resistance. It is when pathogenic bacteria, through integrons, acquire these antibiotic resistance genes that multi-drug resistant 'superbugs' are created.

"In recent years we have developed techniques that allow us to screen and identify antibiotic resistance genes before they get into pathogenic bacteria," says Stokes. "This is an important approach since the widespread use of antibiotics has led to the appearance of antibiotic resistance in many different bacteria in many places. Additionally, bacteria can share genes by spreading them infectiously, a process that can involve bacteria of very different species. This can mean, for example, that a multi-drug resistant bacterium infecting apples in an orchard in the US may have the same antibiotic resistance genes as a difficult to treat bacterium causing a kidney infection in a patient in a Sydney hospital.

"In this broader study we will sample people randomly," says Stokes. "We are not dealing directly with hospitals on the assumption that these genes are found everywhere."

Once Stokes and his colleagues better understand where antibiotic resistance genes are found it may well be possible for doctors and hospital infectious disease clinicians to reduce the chance of antibiotic resistance genes being cast into pathogenic bacteria.