Rapid Microbial ID Direct From Specimen

Abstract This proposal is for BACLIB, a cost-effective, one hour microbial ID test direct from a clinical specimen or positive blood culture. Microbial ID testing is an essential step to appropriate antimicrobial treatment. Today, positive microbial culture indicates a microbial infection, and subsequent microbial ID testing on cultured samples identifies species. Microbial cultures typically take a day to turn positive. During this period, clinicians must treat patients empirically, delaying appropriate therapy, and increasing the risk of sepsis and other adverse events. We have developed BACLIB, a one-hour test that identifies microbial infections directly from positive blood culture (PBC) or urine specimens. BACLIB measures species-specific microbial membrane lipids: lipid A in Gram-negative bacteria, and analogous lipids in Gram-positive bacteria and fungi. These lipids are abundant, easily extracted, and more sensitively detected and identified than analytes used by current tests. In preliminary results with clinical PBC specimens, BACLIB correctly identified 93% of samples. The only available rapid ID test for PBC correctly identified only 61% of these same samples. Thus, BACLIB offers significant advantages over available tests for positive blood culture. BACLIB shows similar performance direct from urine specimens, where there is currently no approved direct-from-specimen ID test. In this proposal, we develop a prototype clinical assay based on BACLIB. The prototype will be evaluated on clinical and prepared specimens and compared with standard methods. The research approach is as follows: Specific Aim 1: Pathogen ID Direct From Specimen. In this aim we identify pathogens direct from PBC and urine using BACLIB. Specific Aim 2. Quantitation of Pathogens Direct From Urine. In this aim we measure the quantity of pathogens in urine, to determine positive urine specimens, defined by microbial concentration. Specific Aim 3. Polymicrobial Specimens. In this aim we evaluate BACLIB in identifying species in clinical and prepared polymicrobial PBC and urine specimens. Appropriate antimicrobial therapy is essential to effective treatment of bacteriuria and bacteremia, and to prevention and treatment of sepsis. These conditions remain major health problems. Furthermore, in the case of sepsis progression is often rapid, so that a single hour saved in diagnosis time can significantly reduce mortality. Faster tests are therefore needed to save lives.