Resistensprofilen

Resistensprofilen, or the resistance profile, is the characterization of a microorganism’s susceptibility to antimicrobial agents. It summarizes which drugs an organism is susceptible to, and which it resists, based on standardized laboratory testing. The profile informs treatment decisions, supports infection control, and underpins surveillance of antimicrobial resistance trends at local, national, and global levels.

Laboratory methods include disc diffusion (Kirby-Bauer), broth microdilution, and automated systems. Results are interpreted using breakpoints defined by standard-setting organizations such as EUCAST and CLSI. The profile is typically reported as susceptible, intermediate, or resistant for each agent, and may include minimum inhibitory concentration (MIC) values.

Applications include guiding empirical and directed therapy, selecting oral versus intravenous regimens, and adjusting treatment in special populations. It also serves as a data input for antimicrobial stewardship programs and for tracking resistance patterns across health care facilities and communities.

Limitations include the potential mismatch between in vitro susceptibility and in vivo efficacy due to pharmacokinetics, host factors, or infection site. Resistance can be due to specific genes or mechanisms such as beta-lactamases, efflux pumps, or target modification. Heteroresistance and mixed populations can complicate interpretation. Continuous updates to breakpoints and testing panels are necessary to reflect current resistance mechanisms.

Resistensprofilen is maintained by clinical microbiology laboratories and public health institutions and is complemented by genomic approaches that identify resistance determinants. It is central to antimicrobial resistance monitoring and to informing treatment guidelines and policy decisions.