TargeT enriched MulTiplex pcr (TeM-pcrTM) for rapid deTecTion of BloodsTreaM infecTions

Bloodstream infection is a leading cause of morbidity and mortality in intensive care units, affecting more than one million Americans annually. The mortality rate associated with bloodstream infection ranges from 10 to 40% and has aggregate healthcare costs of approximately $16 billion a year (1, 2). A rapid (within 24 h) and accurate identification of a broad range of microbial or fungal pathogens is the key for successful management of patients with bloodstream infection. Blood culture is still considered the gold standard in the detection of bloodstream infection, requiring the culture of patient blood in an automated, continuously monitored system followed by Gram staining and subculturing. The practical value of blood culture in the diagnosis of sepsis is impaired by the delay of time-to-results and low sensitivity of slow-growing and fastidious organisms. Every hour of delay for patient treatment of suspected septic conditions results in an increase in patient mortality of 7% (3). Thus, early and accurate detection of blood pathogens will greatly benefit patient care. Molecular diagnostic methods using real-time polymerase chain reaction (PCR) are used routinely for pathogen detection in clinical settings (4–6). Recently, several molecular approaches have been developed to identify a large spectrum of pathogens and antibiotic resistances in a single sample. In this chapter, we describe how target enriched multiplex PCR (TEM-PCR) can be applied for the detection of bloodstream pathogens and the challenges associated with application of multiplex PCR-based tests for testing positive blood culture bottles.