Background: Delayed or misguided management of synovial joint infection can lead to irreversible joint destruction, and result in a dysfunctional joint. In this study we have performed preliminary experiments using Raman spectroscopy as an evolving technology in biofluid analysis and microbial characterization, to explore its potential for rapid diagnosis of pathogenic bacteria in an in-vitro synovial fluid infection model.

Methods: Normal human synovial fluids samples were collected from patients undergoing knee replacement surgery and the three most common pathogenic bacteria introduced in-vitro into the samples. The bacterial growth was systematically monitored using a video micro-sampling Raman spectroscopy system.

Results: The analysis of recorded spectra showed bacterial characteristic Raman bands related to bacterial cell membranes and DNA structures to increase continuously as the incubation period was increased. The marker peaks make gram-positive bacteria S. aureus easily distinguishable from the other gram-negative bacteria. Moreover, Raman Spectroscopy was able to pick-up subtle changes in chemical structure of synovial fluid. Spectra signature recorded from cultured synovial fluid samples showed a significant loss in synovial quality and protein morphology over time compared to control samples.

Conclusion: This study showed the effectiveness of Raman Spectroscopy in detecting and characterizing microbial infection in induced invitro synovial fluid infection model. From a clinical perspective, the use of Raman spectroscopy is likely to add to the armament at the clinician's disposal as an adjunct to current diagnostic methods for quickly and accurately identifying bacteria as early diagnosis, prompt treatment and improve disease prognosis.