Liesman, Rachael M.

ABSTRACT Rapid and accurate laboratory tests are important for the timely diagnosis and treatment of central nervous system infections. The FilmArray meningitis/encephalitis (ME) panel (BioFire Diagnostics, Salt Lake City, UT) is an FDA-cleared, multiplex molecular panel that allows the detection of 14 pathogens (bacterial [ n = 6], viral [ n = 7], and fungal [ n = 1] pathogens) from cerebrospinal fluid (CSF). In this study, we evaluated the performance characteristics of the FilmArray ME panel using clinical, residual CSF samples ( n = 291) that tested positive by a routine method(s) (e.g., bacterial culture, individual real-time PCR assay) for a pathogen represented on the ME panel. Of note, a subset ( n = 76) of the CSF specimens was collected during the prevaccine era and had been characterized as positive for a bacterial pathogen. The FilmArray ME panel demonstrated an overall percent positive agreement (PPA) of 97.5% (78/80) for bacterial pathogens, 90.1% (145/161) for viruses, and 52% (26/50) for Cryptococcus neoformans/C. gattii . Despite the low overall agreement (52%) between the ME panel and antigen testing for detection of C. neoformans/C. gattii , the percent positive agreement of the FilmArray assay for C. neoformans/C. gattii was 92.3% (12/13) when the results were compared directly to the results of routine fungal smear or culture. The FilmArray ME panel offers a rapid (∼60-min), syndrome-based approach for the detection of select meningitis and encephalitis pathogens.

A 61-year-old man with relapsing chronic lymphocytic leukaemia, status post allogeneic stem cell transplant and multiple chemotherapy regimens presented to the emergency room after suffering a grand mal seizure. His evaluation revealed a 1.5–2 cm ring-enhancing left temporal lobe brain lesion on the CT scan. This brain lesion was resected and the histopathology revealed an invasive fungal organism resembling mucormycosis. Amplification and sequencing of the 28S ribosomal RNA gene identified the organism as Rhizomucor pusillus. The patient was treated with liposomal amphotericin B 5 mg/kg every 24 hours for 4 weeks, and then was transitioned to oral posaconazole. Serial brain imaging at 1 and 3 months, while on therapy, showed significant improvement.

ABSTRACT Infective endocarditis is life-threatening; identification of the underlying etiology informs optimized individual patient management. Changing epidemiology, advances in blood culture techniques, and new diagnostics guide the application of laboratory testing for diagnosis of endocarditis. Blood cultures remain the standard test for microbial diagnosis, with directed serological testing (i.e., Q fever serology, Bartonella serology) in culture-negative cases. Histopathology and molecular diagnostics (e.g., 16S rRNA gene PCR/sequencing, Tropheryma whipplei PCR) may be applied to resected valves to aid in diagnosis. Herein, we summarize recent knowledge in this area and propose a microbiologic and pathological algorithm for endocarditis diagnosis.