Comparison of Blood Culture and Multiplex PCR Results in Patients Prediagnosed with Sepsis

Abstract

Aim: Sepsis is a life-threatening infection that affects multiple systems, leading to hemodynamic changes, shock, organ dysfunction, and potentially organ failure. Although blood culture is the gold standard for identifying the causative agent, the pathogen cannot be isolated in some cases, posing significant challenges in diagnosis and treatment, affecting mortality and morbidity rates. The aim of this study is to retrospectively and prospectively evaluate the results of blood cultures and the Multiplex PCR sepsis panel sent to Microbiology laboratory. Material and Method: In this study, 100 samples sent to our laboratory for blood culture and sepsis panel between September 1, 2023, and August 31, 2024, were analyzed retrospectively and prospectively. All bottles with a positive signal were subjected to Gram staining, and simultaneous inoculations were made on 5% sheep blood agar, EMB, SDA, and Chocolate agar. After 24–48 hours of incubation at 37°C, the isolated strains were identified using conventional methods (colony morphology, Gram staining, etc.) and biochemical tests (catalase test, oxidase test, tube and slide coagulase tests). For the sepsis panel, nucleic acid extraction was performed on samples received in the laboratory using a total nucleic acid extraction kit based on magnetic bead technology, following the manufacturer’s instructions. Results: According to the PCR results of the 100 blood samples included in the study, Candida species were detected in 4 samples. Candida species were also identified in the blood culture. The distribution of strains in the sepsis panel included C.tropicalis, C.albicans, C.glabrata, and C.krusei. Among the blood culture samples, three demonstrated results that were consistent with the sepsis panel findings, while one sample was identified as C.glabrata through conventional methods, in contrast to the result from the sepsis panel. Among bacterial pathogens, Staphylococcus spp. was the most frequently identified (56 cases), followed by Escherichia coli. Conclusion: The results of this study demonstrate that PCR is an effective method for diagnosing sepsis; however, some results need to be confirmed by blood culture. PCR testing provides rapid and accurate information, particularly in situations where quick results are essential, such as in intensive care units and emergency departments. However, it should be noted that PCR can amplify DNA from dead bacteria, so results should be interpreted with caution. In clinical practice, the combined use of both tests will contribute to more effective patient management and treatment.

Keywords

• sepsis
• blood culture
• multiplex PCR

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