An evaluation of the Unyvero pneumonia system for rapid detection of microorganisms and resistance markers of lower respiratory infections-a multicenter prospective study on ICU patients

Abstract

Rapid diagnosis of microorganisms and antibiotic resistance is vital for the appropriate treatment of patients with lower respiratory infections, especially for patients in Intensive Care Unit. We conducted a multicenter prospective study to evaluate the ability of the Unyvero pneumonia system for rapid detection from bronchoalveolar lavage fluid (BALF) in China. Eighty-four patients with lower respiratory infections were enrolled, and their BALF samples were collected, and Unyvero, a rapid molecular diagnostic sample-to-answer solution based on multiple PCRs, was applied to detect 21 types of pathogens and 19 types of resistance markers, compared to a routine bacterial culture method. The overall concordance of Unyvero and routine culture was 69/84 (82.1%). Unyvero detected more microorganisms than routine culture (38.1% vs 27.4%, P<0.05) and reported multi-pathogens in more patients than routine culture (10.7% vs 2.4%, P=0.01). The overall sensitivity and specificity of Unyvero for bacteria detection were 84.0% and 98.0%. Besides, Unyvero showed a good performance for antibiotic-resistant bacteria, except Pseudomonas aeruginosa. The concordance was 87.5-100% for methicillin-resistant Staphylococcus aureus and carbapenem-resistant isolates but was only 20-33.3% for Pseudomonas aeruginosa. The high-level semi-quantitative signal intensity of microorganisms detected positive by Unyvero correlates well with positive bacterial cultures. For specimens that were exposed to antibiotic treatment, the Unyvero pneumonia system showed a high concordance with routine bacterial culture and performs well for the detection of antibiotic-resistant bacteria, especially, carbapenem-resistant Klebsiella pneumoniae. It shows promise in guiding the clinical use of antibiotics, such as ceftazidime/avibactam. However, the system needs improvement in detecting resistance markers of Pseudomonas aeruginosa.

Keywords: Antibiotic resistance; BALF; Lower respiratory infections; Microorganisms; Multiplex PCR.