Culture Negative Endocarditis

• Epidemiological factors

• History of prior infections including cardiovascular infections

• Exposure to antimicrobials

• Clinical course

• Severity

• Extra-cardiac sites of infection

Cultures are negative in infective endocarditis for three major reasons:

• Administration of antimicrobial agents prior to obtaining blood cultures

• Inadequate microbiological techniques

• Infection with highly fastidious bacteria or non-bacterial pathogens (eg, fungi)