Antibiotic stewardship with multiplex PCR for pneumonia in intensive care patients: A retrospective study

Background: Early initiation of targeted antibiotic therapy is important to achieve the best patient outcomes in intubated patients with pneumonia in the intensive care unit (ICU). This study aimed to investigate the applicability of multiplex polymerase chain reaction (PCR) in an ICU by comparing the test results to the results of conventional microbiological methods to assess the possible impact on antibiotic therapy. Method: This retrospective study investigated adult patients with pneumonia on mechanical ventilation in the ICU. Tracheal aspirates were collected within 24h after intubation and the initiation of mechanical ventilation. Samples were initially tested by conventional microbiological methods and subsequently re-evaluated with rapid multiplex PCR on stored samples. Concordance between the two methods was assessed. An intensivist and a microbiologist retrospectively reviewed the patients' electronic health records for relevant clinical details to evaluate the potential impact of multiplex PCR results on antibiotic therapy. Results: In this study, 76 patients were enrolled and 55 (72.4%) tested positive for 95 pathogens using multiplex PCR, while conventional microbiological methods identified 40 pathogens in 32 (42.2%) patients. Concordance between the two methods was observed in 42 (55.3%) patients. Multiplex PCR detected 39 additional pathogens in 31 (40.7%) patients. Retrospective analysis indicated potential antibiotic de-escalation in 35 (46.1%) patients and escalation in 4 (5.3%) patients. Multiplex PCR significantly reduced the turnaround time for test results. Conclusion: In ICU patients with suspected pneumonia, multiplex PCR identified a higher number of pathogens compared to CMM. A retrospective assessment indicates that the use of multiplex PCR could potentially have prompted the de-escalation of antibiotic therapy in nearly half of the patients. Therefore, multiplex PCR may serve as a supplement to CMM in guiding antibiotic stewardship.