Ultra-fast and sensitive detection of non-typhoidal Salmonella in human blood samples
Non-typhoidal Salmonella (NTS) are an important cause of invasive bacteremia and focal infections in the USA and globally, which can lead to hospitalization and death especially in infants, the elderly, and the immunocomompromised. In particular, the two most commonly isolated serotypes from blood are Salmonella enterica serovar Typhimurium and S. Enteritidis.
Invasive Salmonella bacteria are routinely detected in 1 to 2 days by standard blood culture techniques. Another several days are required for identification of individual serovars by microbiological techniques. We are proposing to use microwave-accelerated metal-enhanced fluorescence (MAMEF) to detect any Salmonella serovar, and specifically S. Typhimurium and S. Enteritidis, from blood within 4 minutes. We will develop the required DNA probes, based on our experiences with PCR-based detection of NTS, and optimize the assay to achieve high sensitivity and specificity. We will determine whether MAMEF can detect Salmonella directly from blood significantly faster than the currently available techniques, when Salmonella are present at biologically relevant concentrations as low as 0.1 colony forming units per milliliter. Development of a MAMEF-based Salmonella detection strategy will provide an ultra-fast, sensitive, specific, and cost-effective method with multiple applications, including use in surveillance efforts to refine the burden of invasive NTS disease and for identifying cases in possible NTS outbreaks due to natural transmission or deliberate release by bioterrorists.