Identifying antibiotic-resistant Gram-negative bacteria

The new Streck Philisa ampC ID kit enables rapid identification of six plasmid-mediated ampC resistance genes for pathogen surveillance in hospitals and research. When used along with standard culture, this conventional polymerase chain reaction (PCR) kit will help to provide up-to-date information for infection control by identifying which Gram-negative ampC-resistant bacterial strains are present in the hospital. Resistance to the beta-lactam class of antimicrobials is a significant cause of multidrug-resistant urinary tract and bloodstream infections.

The Philisa ampC ID kit, available exclusively in the UK from Alpha Laboratories, is a PCR- based molecular test that detects six of the most common plasmid-mediated ampC gene families (MOX, DHA, ACC, EBC, FOX, CMY). It provides a result in one hour, compared to the two/three days taken by traditional disk-diffusion methods. An endogenous internal control reduces false-negative results.

The test involves a 15-minute PCR step, followed by agarose gel electrophoresis to resolve the PCR products. Their molecular masses are then compared against external controls to provide an indication of genotype. This gives a clear, positive identification of strain genotype and antimicrobial resistance (AMR) potential.

The increased incidence of antibiotic-resistant Gram-negative bacteria is of significant and growing concern. Treatment options for such bacteria are relatively limited and further restricted by the emergence of AMR. Resistance in Gram-negative species is usually associated with beta-lactamase enzymes, of which class C cephalosporinases (AmpC) is one of the best known. Thus, a proper understanding of the specific genotype and susceptibility of a given strain is the key to effective therapeutic intervention.
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