05 Jul Risk of Staph Bacteremia Can Run in Families

MedicalResearch.com Interview with:
Louise Bruun Østergaard MD. Ph.D student
Faculty of Medicine and Faculty of Engineering and Science
Aalborg University
Department of Cardiology, Gentofte Hospital
Hellerup

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Staphylococcus aureus bacteremia strikes people of all ages resulting in devastating consequence even in young and healthy individuals. Animal studies have shown that the susceptibility to Staphylococcus aureus differs among different genetic strains in mice, suggesting that genetic differences could influence the susceptibility to Staphylococcus aureus in other spices. As a first step in determining whether genetics influence risk of Staphylococcus aureus infections we aimed to study whether a family history of Staphylococcus aureus bacteremia in first-degree relatives was associated with risk of the disease.

MedicalResearch.com: What are the main findings?

Response: We observed a highly significant familial clustering of microbiologically verified Staphylococcus aureus bacteremia in individuals with a family history of the infection. Compared with the general population, having a parent previously hospitalized with the disease was associated with a 2.5-fold increased risk, but having a sibling with a history of Staphylococcus aureus bacteremia was associated with a 5-fold increased risk.

The risk of Staphylococcus aureus bacteremia further increased, when the parent or the sibling acquired the infection out-of-hospital. Our results could not be explained by risk factors prone to increase the risk of the infection.

Further, it is unlikely that our findings could be explained by direct transmission of the pathogen, since >80% of individuals acquiring Staphylococcus aureus bacteremia were infected with a strain genetically different from that of their parent/sibling.

Lastly, it appears implausible that our results were driven by shared environmental factors, since the risk of Staphylococcus aureus bacteremia was not increased in spouses.

MedicalResearch.com: What should readers take away from your report?

Response: A family history of Staphylococcus aureus bacteremia was associated with a significantly increased risk of the disease in first-degree relatives. The results of this study increase the awareness and strengthen our hypothesis of a possible influence of human genetics on the susceptibility to Staphylococcus aureus.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: The next step is to determine whether specific genetic factors contribute to the risk for Staphylococcus aureus bacteremia in humans and, if so, to what extent. Such genetic risk factors may be identified by genome-wide association studies (GWAS) identifying common variants or by genome sequencing such as exome sequencing to also identify rare variants associated with the disease. Results from such studies could provide additional information to improve prevention and treatment of Staphylococcus aureus bacteremia.

MedicalResearch.com: Is there anything else you would like to add?

Response: The method used in our study is inspired from cancer research but may be a whole new way of strengthening hypotheses of a possible role of genetics in diseases, prior to large, resource-demanding genome-sequencing and GWAS studies. Our study further emphasizes that particularly in the field of infections, it is crucial to combine register-data with clinical data, e.g. only microbiologically verified events were used, and genetic sequencing of the Staphylococcus aureus bacteria.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

Citation:

Oestergaard LB, Christiansen MN, Schmiegelow MD, Skov RL, Andersen PS, Petersen A, et al. Familial Clustering of Staphylococcus aureus Bacteremia in First-Degree Relatives: A Danish Nationwide Cohort Study. Ann Intern Med. [Epub ahead of print 5 July 2016] doi:10.7326/M15-2762

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on July 5, 2016 by Marie Benz MD FAAD