Real-Time PCR Assay for Detection of Carbapenem Antibiotic Resistance Genes of the IMP-type

Antibiotic resistance is one of the world's most pressing health concerns. ß-lactamases, such as carbapenemases, are enzymes produced by bacteria that provide resistance to multiple ß-lactam antibiotics (e.g., penicillins, cephamycins, and carbapenems) by breaking down the antibiotic molecules and deactivating their antibacterial properties. Carbapenems are broad-spectrum antibiotics often prescribed to treat serious infections in hospitalized patients, and infections with carbapenem-resistant Enterobacteriaceae (CRE) have become a challenge in healthcare settings. Clinical laboratories frequently use phenotypic tests to screen for carbapenemase-producing isolates. However, these phenotypic tests can be difficult to interpret and are unable to identify specific resistance genes. PCR can be utilized to detect the presence of specific resistance genes, such as IMP, and produces rapid results that are easily interpretable. To date, the only FDA-approved and commercially available test for carbapenemase gene screening is restricted to a subset of all IMP genes (IMP-1 subgroup). CDC has developed a primer and probe-based real-time PCR assay with the capacity to detect carbapenemase genes of all currently described IMP variants. CDC's assay has successfully detected IMP genes in multiple bacterial isolates submitted to CDC in cases where the state or public health lab was unable to do so. This assay is easy to perform and implement, and offers a more cost- effective approach than whole genome sequencing.