Serotype-identifying ions in Listeria monocytogenes using matrix-associated laser desorption ionization-time of flight mass spectrometry

Hossam Abdelhamed; Seong Won Nho; Si Won Kim; Joseph S Reddy; Seong Bin Park; Tae Sung Jung; Mark L Lawrence

doi:10.1016/j.heliyon.2022.e11769

Serotype-identifying ions in Listeria monocytogenes using matrix-associated laser desorption ionization-time of flight mass spectrometry

Heliyon. 2022 Nov 19;8(12):e11769. doi: 10.1016/j.heliyon.2022.e11769. eCollection 2022 Dec.

Authors

Hossam Abdelhamed¹, Seong Won Nho¹, Si Won Kim², Joseph S Reddy³, Seong Bin Park⁴, Tae Sung Jung², Mark L Lawrence¹

Affiliations

¹ Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, 39762, USA.
² Laboratory of Aquatic Animal Diseases, Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 660-701, South Korea.
³ Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL 32224, USA.
⁴ Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, MS, 39762, USA.

Abstract

Listeria monocytogenes is a foodborne pathogen that can cause a potentially life-threatening infection, and almost all cases of human listeriosis are caused by L. monocytogenes isolates in serotypes 1/2a, 1/2b, 1/2c, and 4b. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid, accurate, and high-throughput tool for clinical diagnosis and microbiological research. In the current study, we examined the potential of MALDI-TOF MS for rapid identification of the foodborne pathogen L. monocytogenes and to identify high-risk serotypes. To achieve this, MALDI-TOF MS was applied to 50 L monocytogenes strains. All strains were identified as L. monocytogenes species based on pattern matching against reference spectra for the species. Importantly, 83 specific mass ions were consistently and uniquely found in high-risk L. monocytogenes serotypes 1/2a, 1/2b, 1/2c, and 4b. These 83 mass ions were also unique to specific combinations of these serotypes, which enabled specific identification of these four serotypes using MALDI Biotyper analysis. Hence, this method shows potential for using MALDI-TOF MS for the rapid identification of L. monocytogenes species and to discriminate high-risk L. monocytogenes serotypes through specific serotype-specific biomarker ions.

Keywords: Biomarker; Listeria monocytogenes; MALDI-TOF mass Spectrometry; Serotype.