Matrix assisted laser desorption/ ionization time of flight mass spectrometry (MALDI-TOF MS) for identification of anaerobic and microaerophilic bacteria from clinical specimens, in comparison with conventional techniques

Abstract

Background and Objectives: MALDI-TOF MS offers a unique combination of flexibility, accuracy, automation and has found benefit in many fields of biological research. Here we investigated MALDI-TOF analysis for the identification of anaerobic and microaerophilic bacteria isolated from clinical specimen and also compared the results with conventional biochemical characterization.

Materials and Methods: The present study was conducted for a duration of 2 years and had obtained Ethical clearance. Bacteria obtained from 1514 specimens were subjected to MALDI-TOF in comparison with conventional techniques. MAL- DI-TOF was done by Extended Direct Transfer technique after a preparatory protein extraction.

Results: Of the 957 isolates of anaerobes and 214 microaerophilic organisms, 552 anaerobes and 154 microaerophilic iso- lates were identified up to species level giving concordant results by conventional techniques. Rest of the strains could be identified only up to genus level by biochemical characterization. MALDI-TOF MS was able to identify more isolates to the species level compared with conventional methods, including several new genera and species including Clostridia, Peptost- reptococcus and Lactobacilli.

Conclusion: Newly recognized and taxonomically rearranged genera, frequently isolated anaerobic and microaerophilic species as well as closely related species could be identified accurately by employing MALDI-TOF MS. Implementation of this technique for identification will shorten the Turn Around Time, reduce the cost in the Microbiology laboratory and improve the patient care with better clinical outcome