PCR-based test developed for diagnosing sepsis

A team from Tongde Hospital of Zhejiang Province (Hanhzhou, China) have developed a test that can rapidly diagnose sepsis, a critically important factor in the outcome of patients.

Sepsis, a complication of bacterial infections, can be life-threatening. Rapid diagnosis of sepsis is crucial as survival rate is time-sensitive – in severe cases it has been reported that survival rate decreases by by 7.6% per hour without treatment. In addition, early identification of the causative pathogen may increase treatment success and avoid the misuse of antibiotics. A broad range, rapid and reliable diagnostic test is therefore of the utmost need.

This study, published recently in the Journal of Clinical Laboratory Analysis, assessed a newly-developed TaqMan-Based Multiplex real-time PCR detection system, demonstrating this could detect the 10 most frequent bacterial pathogens from blood samples.

Blood culture is the current gold standard for the diagnosis of sepsis; however, it is not always highly accurate and does not provide results in a timely manner, taking several days. In contrast, the new system identified bloodstream pathogens within a few hours.

The team designed the primers and TaqMan probes utilized in the test to be complementary to conserved regions in the 16S rDNA genes of a range of bacteria. They then assessed the assay on known bacterial samples and blood samples from patients displaying the symptoms of sepsis.

The researchers discovered that all known samples were detected by the assay, moreover, no PCR products were detected when DNA from other bacteria was utilized. From the 30 patient samples, 18 patients were confirmed positive by Multiplex real-time PCR and seven patients were confirmed positive by blood culture.

Senior author Bing Zhang (Tongde Hospital ) commented: “Interestingly, pathogens in some blood culture-negative cases of sepsis patients were still detected in this study. We speculate that the residual DNA fragments of the bacteria might be detected by this system even if they were destroyed by antibacterial drugs or the immune system.”

The team state this test could present a rapid and accurate method for detecting bacterial sepsis, and could have promising uses in a clinical setting.

Sources: Liu CF, Shi XP, Chen Y, Jin Y & Zhang B. Rapid diagnosis of sepsis with TaqMan-Based multiplex real-time PCR. J. Clin. Lab. Anal. doi:10.1002/jcla.22256 (2017) (Epub ahead of print); http://newsroom.wiley.com/press-release/journal-clinical-laboratory-analysis/new-test-rapidly-diagnose-sepsis


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