Colonisation and infection of patients by methicillin-resistant Staphylococcus aureus (MRSA) represent both a health hazard (especially due to more difficult treatment as a result of MRSA’s resistance to various antibiotics) and an economic burden on the German health care system.

MRSA infections increase morbidity and mortality and cause significantly higher diagnostic and treatment costs (isolation of patients, prolongation of the treatment period or hospital stay). For the development of target-oriented prevention and control strategies, suitable detection methods for MRSA are of crucial importance.

An optochemical sensor that enables rapid MRSA detection directly on site was therefore developed. The optochemical sensor contains a glass fibre. Upconversion particles (UCPs) are bound on the surface of the glass fibre and serve as measurement transducer (upconversion glass fibre). When NIR light is passed through the upconversion fibre, the UCPs are excited to luminesce.
A luminescence of UCPs leads to coupling of luminescent light into the upconversion fibre, which is detected at the photodetector.

Detection principle of the optochemical sensor is based on quenching of the luminescence of UCPs after binding of living MRSA cells labelled by antibody-functionalised gold nanoparticles. This reduces the intensity of luminescent light captured by the photodetector, allowing fully automated determination of MRSA cells using the optochemical sensor.

In hospitals the number of nosocomial MRSA cases can be reduced by early detection of MRSA contaminations, e.g. due to failed cleaning/disinfection measures or the carryover of MRSA (e.g. from isolation rooms).
The prevention of nosocomial MRSA cases is of particular interest to improve patient safety, to reduce the spread of MRSA and optimise the use of increasingly limited financial resources.

The research report is available on request from FRT.