Detecting infections with fluorescent antibiotics

A bacterial infection of an implant, such as an artificial knee or hip, is the worst and most feared complication when implanting a prosthesis. These infections are often very difficult to detect and treat. The current diagnostic tools are not specific or sensitive enough, and can be distressing for patients. Researchers at the UMCG have now developed a new method for detecting bacterial infections using fluorescent antibiotics. Their findings have been published in the 16 October edition of the leading journal Nature Communications.

Current techniques for diagnosing a bacterial infection are indirect (via blood tests, for example) or invasive (via a biopsy) and therefore distressing for patients. Furthermore, it is often difficult to distinguish between a sterile inflammation, which is not caused by a microorganism but by the implant itself (known as a foreign body reaction) and an infection caused by bacteria, such as the common Gram-positive bacterium Staphylococcus aureus.

Vancomycin

Researchers at the UMCG, led by Prof. Jan Maarten van Dijl and Prof. Go van Dam, have discovered that injecting an extremely low dose of an infrared-fluorescent dye linked to the antibiotic vancomycin is a good method for detecting infections caused by Staphylococcus aureus bacteria at an early stage, and making them visible via a special infrared camera. They have demonstrated the technique in mouse models and a new post-mortem human implant model. More research (toxicity testing) and a good production method (GMP/GLP) for fluorescent vancomycin are needed before the new technique can be tested in a clinical study.

An infection occurs in approximately five percent of all current prosthetic bone implants (such as artificial hips) and some thirty percent of open fractures that require fixation with an implant. These infections may originate from the operation itself, or they may develop later when invasively growing bacteria attach themselves to the surface of the implant. The resulting accumulation of bacteria around the implant can cause a severe inflammation. If the infection is not detected and eliminated in time, the bacteria will develop a so-called biofilm on the implant, making them unreachable for antibiotics. The infection then becomes irreversible, requiring long spells in hospital, antibiotics and often replacement of the implant.

Fast, non-invasive diagnostic techniques for bacterial infections are therefore vital. Early detection and treatment of infections will not only save money due to shorter hospital stays and fewer second operations, but will also spare the patients concerned unnecessary distress.

Note for the press

The publication is available via http://www.nature.com/ncomms/2013/131015/ncomms3584/full/ncomms3584.html. For more information, please contact the press information office at UMCG via +31 (0)50 361 22 00