MALDI-TOF MS meets WGS in a VRE outbreak investigation

Area of Science:

• Microbiology
• Infectious Diseases
• Genomics

Background:

• Vancomycin-resistant Enterococci (VRE) pose a significant threat in healthcare settings, particularly in immunocompromised patient populations.
• Accurate strain typing is crucial for effective outbreak investigation and control of VRE infections.

Purpose of the Study:

• To evaluate the complementary utility of MALDI-TOF MS and WGS for VRE outbreak investigation.
• To discuss challenges in defining strain similarity between MALDI-TOF MS and WGS.
• To assess the suitability of MALDI-TOF MS dendrograms for outbreak analysis.

Main Methods:

• Investigation of a VRE outbreak using both MALDI-TOF MS and WGS.
• Analysis of vancomycin-resistant Enterococcus faecium isolates from positive blood cultures of four haematology-oncology patients.
• Comparison of strain relatedness data generated by MALDI-TOF MS and WGS.

Main Results:

• Both MALDI-TOF MS and WGS identified multiple clusters within the VRE outbreak.
• Discrepancies were observed between the two methods, highlighting limitations of MALDI-TOF MS.
• The small patient cohort underscored the need for cautious interpretation of MALDI-TOF MS dendrograms.

Conclusions:

• MALDI-TOF MS and WGS offer complementary insights into VRE outbreaks.
• WGS is superior for definitively determining evolutionary distance between VRE isolates.
• Careful interpretation of MALDI-TOF MS data is necessary, especially in small-scale outbreaks.