Identification of Adult <i>Fasciola</i> spp. Using Matrix-Assisted Laser/Desorption Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry

• Main Authors: Issa Sy, Lena Margardt, Emmanuel O. Ngbede, Mohammed I. Adah, Saheed T. Yusuf, Jennifer Keiser, Jacqueline Rehner, Jürg Utzinger, Sven Poppert, Sören L. Becker
• Format: Article
• Language: English
• Published: MDPI AG 2021-12-01
• Series: Microorganisms
• Subjects: diagnosis; <i>Fasciola gigantica</i>; <i>Fasciola hepatica</i>; fascioliasis; helminth; matrix-assisted laser/desorption ionization time-of-flight (MALDI-TOF) mass spectrometry
• Online Access: https://www.mdpi.com/2076-2607/9/1/82

Fascioliasis is a neglected trematode infection caused by <i>Fasciola gigantica</i> and <i>Fasciola hepatica</i>. Routine diagnosis of fascioliasis relies on macroscopic identification of adult worms in liver tissue of slaughtered animals, and microscopic detection of eggs in fecal samples of animals and humans. However, the diagnostic accuracy of morphological techniques and stool microscopy is low. Molecular diagnostics (e.g., polymerase chain reaction (PCR)) are more reliable, but these techniques are not routinely available in clinical microbiology laboratories. Matrix-assisted laser/desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a widely-used technique for identification of bacteria and fungi; yet, standardized protocols and databases for parasite detection need to be developed. The purpose of this study was to develop and validate an in-house database for <i>Fasciola</i> species-specific identification. To achieve this goal, the posterior parts of seven adult <i>F. gigantica</i> and one adult <i>F. hepatica</i> were processed and subjected to MALDI-TOF MS to create main spectra profiles (MSPs). Repeatability and reproducibility tests were performed to develop the database. A principal component analysis revealed significant differences between the spectra of <i>F. gigantica</i> and <i>F. hepatica</i>. Subsequently, 78 <i>Fasciola</i> samples were analyzed by MALDI-TOF MS using the previously developed database, out of which 98.7% (n = 74) and 100% (n = 3) were correctly identified as <i>F. gigantica</i> and <i>F. hepatica</i>, respectively. Log score values ranged between 1.73 and 2.23, thus indicating a reliable identification. We conclude that MALDI-TOF MS can provide species-specific identification of medically relevant liver flukes.