This online seminar will discuss the advantages of incorporating molecular testing into the microbiology laboratory to aid in the identification of relevant antibiotic resistance mechanisms.
Surveillance of resistance mechanisms, hospital infection control, and epidemiology require accurate detection of extended-spectrum beta-lactamases (ESBLs), AmpC beta-lactamases, and carbapenemases. For example, an important aspect of infection control is to determine how resistance is spread. Is the spread of resistance due to a clonal outbreak or the movement of mobile genetic elements?
The majority of ESBLs and relevant carbapenemases are encoded on mobile genetic elements; however, AmpC production can be either chromosomal- or plasmid-mediated. Several phenotypic methodologies have been developed to address the detection of beta-lactamase genes, but few can detect the production of AmpC, and none can discern the difference between a chromosomal and plasmid-mediated AmpC producer. Furthermore, a major concern for infectious disease personnel is the inability to detect ESBLs in the presence of AmpC production.
Molecular techniques are required to determine the presence of multiple beta-lactamases within a single isolate or to discriminate between different types of beta-lactamases leading to similar beta-lactam susceptibility patterns. In addition, resistance mechanisms are emerging to other antibiotic classes. The challenge for the infectious disease community is to determine when and if to use molecular testing to aid in the identification of relevant resistance mechanisms, especially when encountering complex susceptibility patterns.
This seminar will highlight the most relevant beta-lactamases and the challenges facing the incorporation of molecular testing into the laboratory. Targets in addition to beta-lactamase genes will also be discussed.
