Scientists Uncover New Genetic Insights into Staphylococcus Aureus

New genetic insights into Staphylococcus aureus have been discovered by Australian researchers, showing what makes the bacteria so hazardous when it enters the bloodstream.

Staphylococcus aureus infections, often known as Golden staph, are common but can be fatal if the bacteria reach the circulation and cause sepsis. Golden staph is infamous for developing antibiotic resistance, making it difficult to treat and potentially leading to bad health effects in people infected with a drug-resistant version of the bacteria.

Researchers from the Peter Doherty Institute for Infection and Immunity (Doherty Institute) examined the unique genetic profiles of more than 1,300 Golden staph strains in one of the most thorough studies of its type, published in Cell Reports.

The researchers discovered that, while patient characteristics are important when assessing mortality risks, specific genes are associated with antibiotic resistance, along with the bacteria’s capacity to persist in the blood and evade the effects of antibiotics and the immune system."

The findings, according to Dr Stefano Giulieri, a Clinician-Researcher at the Doherty Institute and the study’s first author, show the diagnostic efficacy of merging clinical and genomic data.

To the best of our knowledge, this is one of the first times that the method we used, called a genome-wide association study (GWAS), has been applied to delve into the role of bacterial genomes, host factors and antibiotics on the course of staphylococcal sepsis. In GWAS, scientists scan the genome of a big collection of bacteria to look for tiny changes (mutations) that show up more often in strains with a certain characteristic, such as antibiotic resistance. Mutations with a strong statistical link are precious clues to figure out how bacteria acquire attributes that are important for patient outcomes.”

Dr Stefano Giulieri, Study First Author and Clinician-Researcher, Doherty Institute

Dr Giulieri added, “Our study uncovered a deeper understanding of the intricate genetic dynamics underlying severe Golden staph infections. It highlights the potential of combining bacterial whole-genome sequencing, clinical data and sophisticated statistical genomics to discover clinically relevant bacterial factors that influence infection outcomes.”

University of Melbourne Professor Ben Howden, Director of the Microbiological Diagnostic Unit (MDU) Public Health Laboratory at the Doherty Institute and co-senior author of the study, stated that this study reflects an important milestone in medical research as it reshapes the strategies against complex health challenges such as Golden staph infections.

By revealing the genes responsible for antibiotic resistance in Golden staph, our GWAS is pointing the scientific community to clearer targets for the development of effective solutions to treat Golden staph bloodstream infections.”

Ben Howden, Study Co-Senior Author and Director, Microbiological Diagnostic Unit (MDU) Public Health Laboratory, Doherty Institute

“By revealing the genes responsible for antibiotic resistance in Golden staph, our GWAS is pointing the scientific community to clearer targets for the development of effective solutions to treat Golden staph bloodstream infections. This knowledge has the potential to shape and enhance our ability to tackle these persistent infections. As bacterial genomes become increasingly available in the clinical routine, we inch closer to customized therapeutic strategies, where treatments will be tailored to the unique genetic makeup of the infecting strain, rather that treating everyone in the same way,” Howden stated.