Mycobacterial inactivation protein extraction protocol for matrix-assisted laser desorption ionization time-of-flight characterization of clinical isolates.

Background: Rapid identification of mycobacteria has been made possible with matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) in recent years. Working with high concentrations of mycobacteria in a PC-3 containment facility makes MALDI-TOF cumbersome and costly. Therefore removing the inactivated isolate's protein extract from the PC-3 facility is needed for efficient identification in a routine PC-2 laboratory.

Methods: This work describes a novel chemical and mechanical disruption protein extraction method, which provides reliable MALDI-TOF results from solid and liquid media, while ensuring laboratory safety.

Results: When compared to sequencing results, 93.9% of the clinical isolates were identified in LJ media and 89% of the clinical isolates were identified in MGIT media.

Conclusion: The MIPE protocol produces a high quality protein extract with improved isolate identification without compromising result turn-around-times or laboratory safety.