**5. Microbiology**

The most predominant organism is *Staphylococcus aureus* (60–90%). In IVDA, there has been an increase in methicillin-resistance and polymicrobial infection [18]. Coagulase-negative Staphylococcus infection occurs more frequently in the presence of prosthetic valves and indwelling central catheters. Although infection with Streptococci can occur (<10%), it remains higher in left-sided endocarditis [19]. There is also increase in infection with Pseudomonas and other gram-negative bacteria. Fungal infection is not uncommon and has been associated with high mortality especially in immunocompromised patients and those with intracardiac devices [20].
