Application of MALDI-TOF MS for the subtyping of Burkholderia pseudomallei strains and comparison with their MLST types.

OBJECTIVE

To evaluate the first application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a typing tool for Burkholderia pseudomallei.

METHODS

A total of 138 B. pseudomallei strains isolated from Hainan, China, were identified and subtyped using MALDI-TOF MS and compared with their multilocus sequence typing (MLST) profiles.

RESULTS

The strains were identified by MALDI-TOF MS using the research use only (RUO) database, and were all correctly identified to the species level. Cluster analysis of all peaks obtained from MALDI-TOF MS did not yield clearly delineated clusters. However, based on the cophenetic correlation analysis of the differential mass spectrometry peaks among the 18 MLST types, all the strains could be divided into four groups. The sequence types exhibited overlapping distributions among various MALDI groups. The comparative analysis of the two methods revealed that the identification capability of MALDI-TOF MS was lower than that of MLST.

CONCLUSION

Our study represents the first application of MALDI-TOF MS for subtyping B. pseudomallei strains and confirmed the potential application of MALDI-TOF MS for subtyping B. pseudomallei. MALDI-TOF MS is a more convenient and cost-effective instrument for the identification and typing of bacteria, as well as a promising supplementary methods for MLST.