Prevalence of Genes in Gram-Negative Bloodstream Isolates Across 66 Hospitals in the United States

Understanding bacterial species at greatest risk for harboring genes is necessary to guide antibiotic treatment. We identified the species-specific prevalence of genes in Gram-negative clinical isolates from the United States. Twenty-four microbiology laboratories representing 66 hospitals using the GenMark Dx ePlex blood culture identification Gram-negative (BCID-GN) panel extracted blood culture results from April 2019 to July 2020. The BCID-GN panel includes 21 Gram-negative targets. Along with identifying genes, it detects major carbapenemase gene families. A total of 4,209 Gram-negative blood cultures were included. genes were identified in 462 (11%) specimens. The species-specific prevalence of genes was as follows: (16%), (14%), (6%), spp. (6%), (5%), species (3%), (2%), (0.6%), and (0.5%). prevalence was 26%, 24%, and 22% among participating hospitals in the District of Columbia, New York, and Florida, respectively. Carbapenemase genes were identified in 61 (2%) organisms with the following distribution: (59%), (16%), (10%), (8%), and (7%). The species-specific prevalence of carbapenemase genes was as follows: (5%), (3%), (3%), species (3%), spp. (3%), (2%), (<1%), (<1%), and (<1%). Approximately 11% of Gram-negative organisms in our US cohort contain genes. genes remain uncommon in organisms beyond , , and Future molecular diagnostic panels would benefit from the inclusion of plasmid-mediated and SHV and TEM extended-spectrum beta-lactamase (ESBL) targets.