Identification of culturable vaginal Lactobacillus species by means of MALDI-TOF MS: a proof-of-concept study

Background: the study of vaginal microbiota is mainly performed by molecular methods. Nevertheless, they are expensive and not easily available in clinical microbiology laboratories. MALDI-TOF MS is being increasingly adopted for fast and accurate identification of pathogens from clinical samples. Aim of this study was to evaluate MALDI-TOF MS for identification of culturable bacterial species directly from plates streaked with vaginal swabs from a population of patients in childbearing age.
Methods: We included women of childbearing age evaluated from October 2020 to October 2021. Identification was performed by means of Vitek® MS system.
Results: A total of 381 patients were included in the study. Mean age was 33.3 years (±7.7) and 218/381 (57.2%) were pregnant. The most frequent isolates were: Lactobacillus crispatus 85/381 (22.3%), Lactobacillus acidophilus/gasseri 77/381 (20.2%) and Lactobacillus iners 64/381 (16.8%), identified with a confidence value of 99.9%. Gardnerella vaginalis was identified in 74/381 (19.4%) patients.
Conclusions: In this proof-of-concept study we found that MALDI-TOF MS has the potential to be used to identify main Lactobacillus species directly from plates streaked with vaginal swabs.