Evaluation of Microbiological Performance and the Potential Clinical Impact of the ePlex® Blood Culture Identification Panels for the Rapid Diagnosis of Bacteremia and Fungemia

Abstract

Molecular rapid diagnostic assays associated with antimicrobial stewardship have proven effective for the early adaptation of empiric therapy in bloodstream infections. The ePlex® BCID (GenMark Diagnostics) Panels allow identification of 56 bacteria and fungi and 10 resistance genes in 90 min directly from positive blood cultures. We prospectively evaluated 187 sepsis episodes at Grenoble University Hospital and retrospectively analyzed the cases to measure the potential clinical impact of the ePlex BCID results. Identification of all pathogens was obtained for 164/187 (88%) bloodstream infections with 100% detection of antimicrobial resistance genes (17 blaCTX-M, 1 vanA, and 17 mecA genes). Only 15/209 (7%) strains were not covered by the panels. Sensitivity for detection of micro-organisms targeted by the RUO BCID-GP, BCID-GN, and BCID-FP Panels was respectively 84/84 (100%), 103/107 (96%), and 14/14 (100%). Interestingly, accurate identification of all pathogens was achieved in 15/17 (88%) polymicrobial samples. Retrospective analysis of medical records showed that a modification of antimicrobial treatment would have been done in 45% of the patients. Treatment modifications would have been an optimization of empiric therapy, a de-escalation or an escalation in respectively 16, 17, and 11% of the patients. Moreover, 11% of the samples were classified as contaminants or not clinically relevant and would have led to early de-escalation or withdrawal of any antibiotic. Detection of resistance genes in addition to identification alone increased escalation rate from 4 to 11% of the patients. Absence of the ePlex result was considered a lost opportunity for therapy modification in 28% of patients.

Accuracy of Broad-Panel PCR-Based Bacterial Identification for Blood Cultures in a Pediatric Oncology Population

“…However, other published evaluations of this panel did not demonstrate the same inaccuracies with Streptococcus spp. ( 8 – 11 ). Among Staphylococcus species, there were two instances where SOC produced a result of coagulase-negative Staphylococcus species and the BCID-GP panel identified Staphylococcus epidermidis .…”

“…However, it is important to note that there are no differences in the two panel constructs between the RUO versions and IVD versions that have received 510k clearance since this study was performed. Studies to-date have largely described its use in adult, general medical populations ( 8 – 11 ). Here, the performance of the GBCID was evaluated in a predominantly pediatric oncology population, providing a unique look at its performance in a high-risk group where rapid diagnostic information for bloodstream infections could be of particular value for clinical care providers.…”

MALDI-TOF MS in a Medical Mycology Laboratory: On Stage and Backstage

“…Although the MBT-Sepsityper and the Rapid Sepsityper provide interesting results in terms of identification accuracy and rapidity, a major drawback is their lack of automation. Even with the Rapid Sepsityper (which is, as previously mentioned, not optimal for yeast identification), when a high number of positive blood cultures have to be handled, it still requires a lot of technical steps, especially when compared to the fully automated identification system based on PCR or microarray [55,56]. Another limiting issue is the price of the test, to be added to the cost of the interpretation module MBT-Sepsityper.…”

Fungal infections diagnosis – Past, present and future

“…ePlex® system (GenMark Diagnosis, USA) is a fully automated platform, incorporating all the necessary steps for the analysis of positive blood cultures. It has a sample preparation system, followed by a multiplex PCR amplification system, and finally the amplicon analysis through electrochemical examination [ 82 , 90 , 91 ]. It has several panels that allow the detection of various pathogens such as gram-negative and gram-positive bacteria, and fungal species, from blood cultures.…”

“…The fungal pathogens that this panel identifies are Candida species ( C. albicans , C. auris , C. dubliniensis , C. famata , C. glabrata , C. guilliermondii , C. kefyr , C. lusitaniae , C. parapsilosis , and C. tropicalis C. krusei ) Cryptococcus neoformans sensu lato , Cryptococcus gattii sensu lato , Fusarium spp, and Rhodotorula spp. [ 90 , 91 ]. The sensitivity of ePlex® system from blood cultures ranged from 99.8 to 100% for fungal pathogens, and specificity of 100% [ 91 , 92 ].…”