Characterization of α-Hemolytic Streptococci Isolated from Clinical Specimens by Matrix-assisted Laser Desorption/Ionization–Time-of-flight Mass Spectrometry

Introduction: Alpha (α) hemolytic streptococci, also referred to as Viridans group Streptococci (VGS), are normal flora of the respiratory tract and can act as opportunistic pathogens, resulting in a variety of illnesses, from mild to severe, life-threatening conditions.This study investigates the efficacy of matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) for the rapid and accurate identification of α-hemolytic streptococci.Materials and methods: Clinical strains of α-hemolytic streptococci isolated from atypical pneumonia, bacterial meningitis, bacteremia, otitis media, and various respiratory tract infections for 2 years and 3 months in a tertiary care center in Coastal Karnataka were subjected to MALDI-TOF analysis by the extended direct transfer (eDT) technique.Results: Of the 247 isolates of α-hemolytic streptococci, the major isolate was Streptococcus mitis (30.7%), followed by S. oralis (25.5%) and S. pneumoniae (18.6%).Others include S. parasanguinis (10.12%) and S. salivarius (7.29%), respectively.Conclusion: Conventional methods for identifying these bacteria often involve lengthy and complex processes, which can delay treatment.Our research employed MALDI-TOF to analyze the reliability of α-hemolytic streptococci isolates within a few minutes.Our study revealed a significant prevalence of invasive streptococcal infections in our institute, with a notable predominance in male patients and the geriatric age group.The most common source of Streptococcus isolates was respiratory samples, indicating the respiratory tract as a primary site of infection.