Usage of Multiplex Polymerase Chain Reaction (PCR) Panels at a Single Tertiary Hospital in Manila: Most Common Pathogens Detected and Implications on Antimicrobial Therapy

Background and Objectives. Multiplex Polymerase Chain Reaction (PCR) is an emerging diagnostic tool used to rapidly detect infectious disease pathogens, aiding decision-making in antimicrobial therapy. This study aims to describe the usage of multiplex PCR (BioFire® FilmArray®) panels, namely Respiratory Panel, Pneumonia Panel, Gastrointestinal (GI) Panel and Meningitis/Encephalitis (ME) Panel in adult patients in a tertiary hospital in Manila, from 2020 to 2023 (2021 to 2024 for Meningitis/Encephalitis Panel); to identify the most common pathogens detected for each panel; and to determine the implications on antimicrobial therapy.

Methods. Panel results were retrieved with assistance from the laboratory staff through the hospital information systems (HIS), and patient demographics and antimicrobial therapy from the HIS. Descriptive analysis was done.

Results. Among adult patients subjected to Multiplex PCR panels in Asian Hospital and Medical Center in the period specified above, the most requested was the Respiratory panel, followed by the Pneumonia panel, GI panel, and ME panel. Pneumonia panel has the highest positivity rate at 61%, followed by the GI panel at 42.1%, the ME panel at 40%, and the respiratory panel at 18.3%. The majority of the respiratory panel pathogens were communityacquired, with SARS-CoV-2, Influenza A, and Rhinovirus/Enterovirus as the most commonly detected pathogens. Pneumonia panel pathogens were mostly hospital-acquired, with Pseudomonas aeruginosa and Klebsiella pneumoniae (with resistance genes CTX-M and NDM) being the most commonly detected. The sample size is much smaller for the remaining panels. The most commonly found pathogens in the GI panel were the Enteroaggregative and Enteropathogenic Escherichia coli and Clostridium difficile, and for the ME panel, Streptococcus agalactiae and Varicella zoster virus. Overall, awareness of the etiologies of infectious diseases through multiplex PCR panels led to starting of new antimicrobials and the continuation of the present antimicrobials, more than shifting or stopping antimicrobials.

Conclusion. This study determined the most common pathogens detected in Multiplex PCR panels in Asian Hospital and Medical Center as above. Awareness of the etiologic agents for all 4 panels appeared useful in the decision-making on antimicrobial therapy. In the respiratory panel, the majority resulted in starting new antimicrobials (32.4%), followed by continuing antimicrobials (23.1%). In the pneumonia panel, it seemed like the majority had already started the appropriate empiric therapy since most continued with the present antibiotics (51.7%), followed by starting (22.8%) and shifting (18.3%) antimicrobials. In the GI panel, most also continued with the current antibiotics (29.5%), closely followed by starting (17.6%), remaining without antimicrobials (17.6%), and shifting antimicrobials (11.8%). It is in the ME panel that most started with new antimicrobials (44.5%) and stopped (33.3%) specific antimicrobials. The study underscores the value of multiplex PCR in enhancing diagnostic accuracy and guiding antimicrobial decision-making.