Role of prolonged blood culture incubation in infective endocarditis diagnosis

Excerpt

We read with interest the recent publication by Lindell et al. describing a large cohort of Cutibacterium/Propionibacterium prosthetic valve endocarditis (PVE) [1]. Cutibacterium/Propioniobacterium species are facultative anaerobes which are part of the normal skin microbiota and are increasingly recognized as a cause of endovascular infection, in recent reports, constituting 3.8–8% of PVE cases [1, 2]. As slow-growing organisms, Cutibacterium/Propionibacterium species may require prolonged durations of incubation for isolation. Accordingly, they may be missed with conventional durations of blood culture incubation. Prolonged blood culture incubation is frequently requested by the Infectious Diseases clinicians at our institution in cases of suspected endocarditis; however, the clinical value of this practice has been incompletely defined. Likewise, the clinical value of blind subcultures and terminal Gram or acridine orange staining of negative blood culture bottles in such situations is not clear [3]. Terminal subculture to chocolate agar is recommended by the Clinical and Laboratory Standards Institute (CLSI) for patients with suspected endocarditis who have negative blood cultures after 5 days. …