Genotyping Staphylococcus aureus in Endocarditis Using Multilocus Sequence Typing

Background: Infective endocarditis (IE) is a rare but life-threatening infection that can occur post-cardiac valve surgery, with Staphylococcus aureus (SAB) being the leading causative pathogen due to its virulence and resistance traits. Specific Background: Molecular typing methods like multilocus sequence typing (MLST) offer improved resolution in understanding SAB epidemiology compared to conventional culture-based techniques. Knowledge Gap: However, the clonal diversity and genetic lineages of SAB isolates associated with IE in regional healthcare settings remain underexplored, particularly in populations with low culture positivity. Aims: This study aimed to genotype SAB isolates from IE patients using MLST to investigate their strain-level diversity, clonal relationships, and antibiotic resistance profiles. Results: Among 281 blood samples, only 43 (15.3%) yielded bacterial growth, with 11 (25.6%) confirmed as SAB. MLST revealed genetic heterogeneity, identifying ST-1 (biofilm-associated), ST-21 (community-acquired), ST-215 (healthcare-related), and emerging regional clones ST-59 and ST-531. Novelty: This study presents the first molecular characterization of SAB in IE patients in this region, linking sequence types to clinical contexts. Implications: Findings underscore the utility of MLST in identifying transmission patterns, informing infection control strategies, and highlighting the need for ongoing molecular surveillance of multidrug-resistant SAB strains. Highlights: Staphylococcus aureus causes infective endocarditis post-heart valve replacement surgery. Used MLST to genotype SAB; found ST-1, ST-21, ST-215. MLST reveals SAB diversity; aids targeted control of resistant regional strains. Keywords: Infective endocarditis (IE), S.aureus, genotyping, multilocus sequence typing, biomarkers