Reliability Evaluation of MALDI-TOF MS Associated with SARAMIS Software in Rapid Identification of Thermophilic Campylobacter Isolated from Food

Abstract

Thermophilic Campylobacter species represent the most frequent cause of food-borne disease worldwide. Biochemical and serological tests, according to ISO 10272:2017, are routinely used in microbiology laboratories for their detection/identification. However, these procedures require a lot of time and can incur in diagnostic mistakes. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is considered a promising identification method for bacteria and fungi from clinical isolates. The aim of this study was to evaluate the reliability of MALDI-TOF MS associated with SARAMIS software, in rapid identification of food-related Campylobacter spp., considering that this method was tested only on human and animal clinical strains. A total of 276 putative thermophilic Campylobacter strains, isolated from different foodstuffs according to ISO 10272-1:2006, were identified comparing the results of MALDI-TOF MS/SARAMIS with Multiplex PCR assay. MALDI-TOF MS/SARAMIS correctly identified 96% (n = 267) of strains at the species level, while only 2.5% (n = 7) of strains were not identified. Misidentification occurred in 0.7% (n = 2) of samples. The performance of this method demonstrated an overall sensitivity (Se) of 97.45% and specificity (Sp) of 100%. Thus, this method can be used for the rapid identification of Campylobacter strains isolated from food samples according to ISO 10272:2017.