Enhanced tick species identification in a tertiary care hospital using MALDI-TOF MS: The role of peak numbers.

Introduction: Tick bites are a growing public health concern as ticks act as vectors for various pathogens. Accurate tick species identification is vital to assess disease exposure and determine prophylactic measures. MALDI-TOF MS has emerged as a promising tool for precise tick identification. This study evaluates the performance of MALDI-TOF MS in clinical tick identification, focusing on how the number of peaks present in the reference and sample spectra influences the accuracy of the identification process.

Methods: Between April 2022 and March 2024, 42 tick specimens sent to our hospital were identified using MALDI-TOF MS. The reference spectrum was created with 70 peaks and expanded to include versions with 40, 100, and 130 peaks using Compass Biotyper Explorer v4.1.1. Spectra were analyzed with Flex Analysis v3.4 software. Identification was performed by querying sample spectra against these libraries, with a log score value (LSV)≥1.70 considered accurate for species identification.

Results: Libraries with 40, 100, and 130 peaks improved identification scores for several species, though the degree varied. The highest scores were achieved in 64.3% of specimens. Combining all libraries as a single database yielded LSVs above the 1.70 threshold for all specimens.

Conclusions: The study highlights the species-specific nature of peak importance in spectra and underscores the potential of MALDI-TOF MS as a rapid and accurate tool for tick identification in clinical settings. Enhanced spectral libraries could further improve this technique, aiding timely clinical decisions and effective management of tick bites.