An investigation of the role of Staphylococcus aureus colonisation of healthcare workers in nosocomial transmission of S. aureus to patients in an MRSA-endemic setting using whole-genome sequencing

Staphylococcus aureus is a bacterium that frequently causes serious infections among hospitalised patients. This includes methicillin-susceptible S. aureus (MSSA) that are readily treatable with antibiotics and the so-called antibiotic resistant "superbug"MRSA (methicillin-resistant S. aureus). MRSA have been widespread in Irish hospitals for 30 years where the level of MRSA causing life-threatening bloodstream infections (BSIs) is currently 10-times higher than many Northern-European countries. Furthermore, the number of MSSA causing BSIs has increased among hospitalised patients in Ireland in recent years.

Approximately 30% of healthy people carry S. aureus in their nose and mouth. This is often higher among healthcare workers (HCWs), particularly in hospitals where S. aureus infections are common. HCWs have close contact with patients and S. aureus from their noses can infect patients. Information on the role of S. aureus carriage by HCWs in transmission to patients in hospitals with a significant history MRSA are scarce with no published Irish data. Current Irish MRSA guidelines only recommend testing HCWs for S. aureus carriage during infection outbreaks and in high-risk units.

This project aims to investigate how commonly and for how long S. aureus is carried in the noses and mouth/throat of HCWs and whether some of these are transmitted to patients and how often. The study will be undertaken in a large Irish hospital with a long-term history of MRSA infections. Sophisticated laboratory techniques that examine the entire genetic sequence of S. aureus DNA will be used for detailed comparisons of S. aureus from HCWs, patients and frequently touched hospital surfaces. These investigations will reveal if HCWs are a significant source of S. aureus patient infections in a hospital where MRSA infections are common. This information can be used to revise national policy on screening and eradication of S. aureus carriage among HCWs to reduce patient infections.


Award Date
20 October 2016
Award Value
Principal Investigator
Professor David Coleman
Host Institution
Dublin Dental University Hospital
Health Research Awards