Improving the Diagnosis of Bloodstream Infections: PCR Coupled with Mass Spectrometry

Jordana-Lluch, Elena; Giménez, Montserrat; Quesada, M. Dolores; Ausina, Vicente; Martró, Elisa

The ideal diagnostic platform should identify a broad spectrum of pathogens (bacteria, fungi, viruses, and protozoa), determine the susceptibility to a battery of antibiotics, allow the analysis of specimens in high or low throughput, have a low cost per sample, have minimum hands-on time, be user friendly, and, ideally, generate the results in a timely manner for the management of septic patients (6 hours or less). Mass spectrometry technology has recently been introduced in the clinical microbiology laboratory. Using matrix-assisted laser ionization time-of-flight (MALDI-TOF) spectrometers the diagnostic process may be shortened [5] [6] [7] as the identification of the pathogen can be achieved within 30 minutes directly from a positive blood culture [8] . Additionally, this technology is able to detect the resistance to some antibiotics [9] , such as the presence of -lactamases (including carbapenemases), methicillin-resistant Staphylococcus aureus, and even vancomycin-resistant Enterococcus spp. However, this technology relies on culture and, therefore, a median of 12-to 17-hour delay is unavoidable [4] . In order to further accelerate the diagnostic process, it is desirable to detect and identity pathogens directly from the patient's blood, avoiding the culture step.