Journal Article

Usefulness of point-of-care multiplex PCR to rapidly identify pathogens responsible for ventilator-associated pneumonia and their resistance to antibiotics: an observational study

Combes, Alain, Bonnet, Isabelle, Hékimian, Guillaume, Robert, Jérôme, Aubry, Alexandra, Bréchot, Nicolas, Schmidt, Matthieu, Luyt, Charles-Edouard

2020

Overview

Background The use of multiplex PCR to shorten time to identification of pathogens and their resistance mechanisms for patients with ventilator-associated pneumonia (VAP) is attractive, but poorly studied. The multiplex PCR–based Unyvero pneumonia cartridge assay can directly identify 20 bacteria and one fungus, amongst the most frequently causing VAP, and 19 of their resistance markers in clinical specimens (bronchoalveolar lavage or tracheal aspirate), with a turnaround time of 4–5 h. We performed this study to evaluate the concordance between the multiplex PCR–based Unyvero pneumonia cartridge assay and conventional microbiological techniques to identify pathogens and their resistance mechanisms in patients with VAP. Methods All patients suspected of having VAP (January 2016 to January 2019), who underwent fiberoptic bronchoscopy with bronchoalveolar lavage fluid (BALF) and whose BALF microscopy examination revealed intracellular bacteria, were included. BALF conventional cultures (gold standard), antimicrobial susceptibility testing and processing for the Unyvero pneumonia cartridge were done. Culture and Unyvero results were compared. Results Compared to cultures of the 93 samples processed for both techniques, Unyvero correctly identified pathogens in 68 (73%) proven VAP episodes, was discordant for 25 (27%), detected no pathogen in 11 and overdetected a not otherwise found pathogen in six. For the eight remaining discordant results, the pathogen responsible for VAP was not included in the Unyvero cartridge panel or it grew at a non-significant level in culture. Amongst the 31 (33%) resistance mechanism discordances observed, 22 were resistance detection failures and 24 concerned Pseudomonas aeruginosa . Conclusions Compared to conventional microbiological cultures, the Unyvero pneumonia cartridge had poor diagnostic performance: it correctly identified pathogens and their resistance mechanisms in 73% and 67% of VAP cases, respectively. The lack of performance on the resistance mechanism was more pronounced when the pathogen detected was a Pseudomonas aeruginosa .

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Adult / Anti-Bacterial Agents - therapeutic use / Antibiotics / Antimicrobial agents / Antimicrobial stewardship / Bacteria / Bacteriology / Bronchoalveolar Lavage - methods / Bronchoalveolar Lavage Fluid - microbiology / Critical care / Critical Care Medicine / Data collection / Drug Resistance, Microbial - drug effects / Drug Resistance, Microbial - physiology / E coli / Emergency Medicine / Female / Fiber optic equipment / Humans / Identification / Intensive / Laboratories / Life Sciences / Male / Medicine / Medicine & Public Health / Methicillin / Methods / Microbial drug resistance / Microbiology and Parasitology / Microorganisms / Microscopy / Middle Aged / Multiplex PCR / Multiplex Polymerase Chain Reaction - methods / Multiplex Polymerase Chain Reaction - standards / Multiplex Polymerase Chain Reaction - statistics & numerical data / Observational studies / Pathogenic microorganisms / Pathogens / Patients / Pneumonia / Pneumonia, Ventilator-Associated - diagnosis / Pneumonia, Ventilator-Associated - diagnostic imaging / Point-of-Care Systems - standards / Point-of-Care Systems - statistics & numerical data / Simplified Acute Physiology Score / Ventilator-associated pneumonia / Ventilators