Don’t request routinely extended incubation of blood cultures in suspected endocarditis.
|Rationale and Comments:||Extending incubation of routine blood cultures does not increase the recovery of clinically significant pathogens causing endocarditis. Five-day incubation, using currently available media formulations and automated incubation and detection systems, is sufficient to recover the majority of true pathogens including HACEK \organisms. Alternative methods (such as serology, molecular, targeted fungal or mycobacterial cultures, or tissue histopathology) should be utilized, when clinically indicated, for detection of rarely encountered, fastidious organisms (Bartonella, Coxiella, Mycobacterium, dimorphic fungi) not recovered using routine blood cultures. Occasional exceptions may be appropriate and should be reviewed in consultation with an infectious disease specialist.|
|References:||• Baron EJ, Scott JD, Tompkins LS. Prolonged incubation and extensive subculturing do not increase recovery of clinically significant microorganisms from standard automated blood cultures. Clin Inf Dis. 2005;41(11):1677-1680.
• Liesman RM, Pritt BS, Maleszewski JJ, Patel R. Laboratory diagnosis of infective endocarditis. J Clin Microbiol. 2017;55(9):2599-2608.