Biofilms in medical devices: resistance
Detection and diagnosis
The symptomatology of infections associated with biofilm infection comprise fever and persistent inflammatory reaction at a specific place. When these signals emerge, additional tests are performed to determine the cause of the infection (Mihai et al., 2015). There are only few methods to allow the identification of biofilms in clinical settings. The most used microbiological method to detect bacterial growth is the plate counting, where swabs of the medical devices are grown in an agar plate and the determination of colony-forming units is performed. However, this method has several disadvantages such as lack of information about the biofilm maturity and heterogeneity. Therefore, nowadays the most used technique is microscopy with specific fluorescent markers. Others advanced microscopy methods such as scanning laser microscopy, SEM and AFM can be used to determine biofilm’s morphology, cell-surface attachment, and in situ cell-cell interaction (Donlan, 2001a; Lindsay and von Holy, 2006; Wu et al., 2015; Mihai et al., 2015).
The long duration of these methods leads to the development of alternative techniques to determine the origin of the infection, such as fluorescence in situ hybridization and matrix-assisted laser absorption coupled with MALDI-TOF (Suleman et al., 2014).