For polymicrobial infections, AtbFinder utilizes a novel paradigm of the population response to antibiotics, enabling bacterial growth in the form of a mixed microbial community and selecting the antibiotics targeting not only the principal pathogen, but also those bacteria that support their growth. TGV medium allowed culturing a more diverse set of bacteria from polymicrobial biospecimens, compared with that achieved with the standard media and enabled, already within 4h, accurate selection of the antibiotics that completely eliminated all cultivatable bacteria from clinical samples. In conclusion, AtbFinder system may be a valuable tool in improving antibiotic selection, enabling targeted empirical therapy and accurate antibiotic replacement, which is especially important in high-risk patients.

Rapid diagnostic tests are needed to improve patient care, particularly in immunocompromised hosts. Here, we describe the validation of a new phenotypic culture-based FAST-T method for rapid selection of antibiotics in vitro using specimens with mono- and polybacterial infections. FAST-T approach, which can be applied to any type of non-blood tissue, does not require isolation of pure bacterial cultures. FAST-T-selected antibiotics are those that can completely eliminate mixed bacterial infections in specimens. The method uses a novel FASM-T medium that allows more rapid bacterial growth of gram-positive and gram-negative monoisolates compared with that achieved with conventional laboratory media. The application of the FAST-T method in 122 bacterial species demonstrated overall sensitivity, specificity, positive predictive value, and negative predictive value of 99.6%, 98.1%, 98.5%, and 99.4%, respectively, already after 4 h. The overall category agreement with the outcome of standard testing was 98.9% with very major errors and major errors being detected in 1.2% and 0.6% of cases. The use of FASM-T medium in 20 clinical polymicrobial samples allowed culturing a more diverse set of bacteria, including fastidious species, compared with that achieved with the standard laboratory diagnostic and enabled, already within 4 h, accurate selection of the antibiotics that completely eliminated all cultivatable bacteria from clinical samples. In conclusion, FAST-T system may be a valuable tool in improving phenotypic-based antibiotic selection, enabling targeted empirical therapy and accurate antibiotic replacement, which is especially important in high-risk patients.