Clinical evaluation of multiplex pathogen real-time PCR for early detection of pathogens and antimicrobial resistance genes in intra-abdominal infections.

Rapid pathogen identification is essential for the management of post-operative intra-abdominal infections. However, conventional culture is often time-consuming and has limited pathogen coverage. Our study aimed to evaluate the performance of multiplex pathogen real-time polymerase chain reaction (MP-PCR) in detecting pathogens and antimicrobial resistance genes (ARGs) from postoperative drainage fluids. A total of 63 drainage fluid specimens were prospectively collected from 52 patients who underwent abdominal surgery and were included in the final analysis. All specimens were detected in parallel using conventional culture and MP-PCR, and a set of specimens were further validated via targeted next-generation sequencing(tNGS). MP-PCR yielded significantly higher positive detection rates than conventional culture at both the patient level (73.1% vs. 57.7%) and specimen level (76.2% vs. 61.9%). Pathogen spectrum analysis revealed that bacteria constituted the predominant pathogens identified by both methods, whereas MP-PCR exhibited a broader pathogen spectrum. MP-PCR showed higher frequencies for major clinically relevant bacteria associated with intra-abdominal infections and demonstrated substantial consistency with conventional culture results. Additionally, the identification of ARGs (mainly AmpC and KPC) shown excellent consistence with antimicrobial susceptibility test (AST). Furthermore, tNGS further validated the reliability of MP-PCR-based pathogen identification. In conclusion, these findings suggested that MP-PCR serves as a robust and complementary molecular tool for the early detection of pathogens and ARGs in postoperative drainage fluids, holding great potential to optimize the diagnosis and targeted treatment of postoperative intra-abdominal infections.