Emergency management in bacterial meningitis and sepsis: application of real time-polymerase chain reaction and FilmArray technology performed directly on cerebrospinal fluid and blood samples

Abstract

<em>Background</em> <em>and</em> <em>Aims</em>. Bacterial meningitis and sepsis are medical emergencies where tests with a high sensitivity and short turn around time (TAT) are crucial for an early targeted therapy. Aim of this study was the evaluation of an optimal diagnostic strategy for infectious meningitis/sepsis management, assessing seven methods: cerebrospinal fluid (CSF) physical-chemical examination, CSF cultural tests (CCT), Gram stained smears (GSS), CSF latex agglutination test (CLAT), blood culture (BC), Real-Time (RT)-PCR and FilmArray Technology (FAT) performed directly on CSF/blood. <br /><em>Materials</em> <em>and</em> <em>Methods</em>. Samples of CSF (240), blood (180) and cavitary fluids (9) were tested by commercial RT-PCR (Eurospital and Liferiver kits) and traditional methods. Positive samples (BC and RT-PCR) were tested by FAT (Blood Culture Identification Panel, Biofire, Salt Lake City, UT, USA) performed directly on CSF, blood and cavitary fluids. <br /><em>Results</em>. In CSF, GSS, CLAT, CCT, RT-PCR and FAT sensitivity was 41%, 35%, 41%, 100% and 62,5%, respectively. In blood, BC, RT-PCR and FAT sensitivity was 96%, 70% and 44%, respectively. TAT was 48-96 hrs, 3 hrs and 1 hr and NPV was 98%, 89% and 57%, respectively. <br /><em>Conclusions</em>. For sepsis management, RT-PCR is faster than BC (3 hrs vs 24-72 hrs), but limited by a low overall sensitivity (70%), due to the low number of detectable pathogens; FAT, performed directly on positive BC should replace biochemical identification (Vitek 2, Biomérieux Marcy-l’Étoile, France) reducing TAT (1 hr <em>vs</em> 12 hrs). For meningitis management, RT-PCR is the most sensitive and rapid method used in routine and emergency regimen. It is cost effective and it represents the gold standard for diagnosis and follow-up of patients under treatment. For meningitis management, FAT, with a higher sensitivity and rapidity and an easier and objective interpretation, should replace CLAT and GSS in emergency regimen.

CSF in acute and chronic infectious diseases

“…With the elimination of DNA extraction, there is no DNA loss and thus, lower numbers of bacteria are detected compared to traditional rt-PCR, well within the range detected by culture (Wu et al, 2013;Bloch and Tang, 2016;Vuong et al, 2016). In addition, direct rt-PCR conserves precious CSF specimens as it only requires 2 mL of CSF per reaction (Bianchi et al, 2015;Bhagchandani et al, 2016;Vuong et al, 2016).…”