‘Sample-in, answer-out’? Evaluation and comprehensive analysis of the Unyvero P50 pneumonia assay

• Clinical evaluation of the PCR based Unyvero P50 test for rapid diagnosis of pneumonia.
• More bacterial species detected compared to routine culture, which may be contribute to disease.
• Straight from specimen detection fails to link resistance genes with organisms of origin.
• Such data must be carefully managed to avoid compromising antimicrobial stewardship.

This study aimed to evaluate the performance of the Unyvero P50 pneumonia assay, the first ‘sample-in, answer-out’ system for rapid identification of pathogens and antibiotic resistance markers directly from clinical specimens. Overall, Unyvero P50 displayed very good sensitivity (>95%); however, specificity was low (33%) mainly because 40% of the specimens were reported as normal flora. Specifically, one or more pathogens were identified in 28 of them. From a detailed analysis of 42 specimens selected at random, 76% of the additionally reported pathogens were confirmed present in primary specimens. Detection of selected resistance markers was compared to routine phenotypic susceptibility testing, supplemented with Checkpoints microarray system, PCR and sequencing. Concordance was mixed, primarily due to issues with panel’s choice of markers and detection of some intrinsic beta-lactamases. Finally, we offer a critical analysis of the assay’s microbial panel and resistance markers and provide suggestions for improvement.