New approaches to the detection of echinocandin resistance in Candida glabrata in clinical diagnostic laboratories

Candidaemia is widely reported as the fourth most common form of bloodstream infection worldwide. Reports of cases of candidaemia whilst patients are in receipt of antifungal therapy are increasing, and this is especially relevant as prescribing practices change and develop. Given the elevation of echinocandin antifungal agents as first line treatment options over triazole agents and the use of echinocandin antifungal agents as prophylactic agents, it is important to maintain awareness of the potential difficulties surrounding emergent antifungal resistance.This study has designed and created a suitable assay for the specific detection of FKS gene mutations in Candida glabrata to indicate resistance to echinocandin antifungal agents using a pyrosequencing-based platform in the clinical diagnostic laboratory. There exists the potential for this rapid molecular detection system to be used as a screening tool which would help provide clinicians with essential information required to make appropriate and accurate therapeutic decisions for the management of bloodstream infections. This assay allows the reporting of these results within 4 hours of isolation greatly improving reporting times in the clinical laboratory.This study has also attempted to demonstrate the potential of proteomic approaches, using LC MS/MS and MALDI-TOF MS, to indicate antifungal resistance as demonstrated by C. glabrata with the echinocandin antifungal agents, by the identification of proteins, the changing patterns of protein presence, absence or relative abundance. This study has solely focused on using techniques that are realistically accessible to a diagnostic microbiology laboratory to maintain a true clinical impact. No readily identifiable or reproducible patterns were found, however the importance of continuing to adapt and modify the capabilities of the modern clinical diagnostic laboratory in an era of increasing antimicrobial resistance is highlighted. This study also provided data to support the continual low level of echinocandin resistance prevalent in C. glabrata in the United Kingdom