Background: Community-acquired pneumonias (CAP) hospitalized in intensive care units (ICU) are a common cause of antibiotic prescriptions. The recent availability of respiratory multiplex PCR assays, that identify a panel of viral and intracellular pathogens in less than 2 hours, could be a useful tool for antimicrobial stewardship and thus optimize and reduce antibiotic consumption. Nevertheless, data concerning the real-life impact of those tools are lacking.
Materials/methods: We performed a monocentric retrospective study including all patients admitted to the ICU for a CAP with a positive BIOFIRE® Respiratory Panel (BIOFIRE® RP), from September 2018 to July 2019. This test detects 15 virus and 4 bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae, Bordetella pertussis, Bordetella parapertussis). Definition of CAP for inclusion in this study was: at least one respiratory clinical symptom and temperature ≥38 or <36°C or leucocyte ≥10 or <4 G/L and radiological image compatible with CAP. All medical charts were reviewed by 2 infectious-disease specialists and 1 intensive care specialist.
Results: During the period study, 70 respiratory multiplex PCR assays were performed among patients hospitalized in the intensive care unit, 33 were excluded because they did not meet inclusion criteria. Among the 37 patients included, sex ratio was 0.46 and mean age was 69.9. The mean IGS II score was 43 (median: 41, IQR: 13) and the mean Fine score was 125 (median: 122, IQR: 73). Thirty-five PCR test results (94.6%) were positive for viral agents (15 influenza viruses, 2 respiratory syncytial viruses and 22 other viruses) and 2 for Mycoplasma pneumoniae. Regarding usual bacterial respiratory samples, 26/37 (70.3%) cultures were positive for bacteria. Modification of the antibiotic treatment was assessed for the 2 cases with a PCR positive for Mycoplasma. For every other patient (n=35), antibiotherapy was not modified, even for patients with no microbiological identification of bacterial infection (n=9).
Conclusions: In our experience, the impact of respiratory PCR assays on antibiotherapy in patients hospitalized for CAP in ICU is weak. Only flu and intra cellular bacteria detection seem useful for patient management. Cost effective study should evaluate more precisely the interest of those tests.