cephalosporinresistant

Cephalosporinresistant describes microorganisms that show reduced susceptibility to cephalosporin antibiotics, a class of beta-lactams used to treat a wide range of infections. Cephalosporins vary in spectrum and generation, but resistance to this class has become common in many settings, complicating empirical therapy and necessitating susceptibility testing.

The main resistance mechanisms include production of beta-lactamase enzymes that hydrolyze cephalosporins, such as extended-spectrum beta-lactamases (ESBLs), AmpC beta-lactamases, and, less frequently, carbapenemases that degrade a broad range of beta-lactams. Other mechanisms include alterations of penicillin-binding proteins that reduce drug affinity, decreased outer membrane permeability due to porin loss, and active efflux pumps that remove the antibiotic from the bacterial cell. These mechanisms can be intrinsic to certain species or acquired through horizontal gene transfer on plasmids, transposons, or integrons, contributing to rapid spread.

Clinically important examples include many Enterobacterales (notably Escherichia coli and Klebsiella pneumoniae) that carry ESBL or AmpC genes, leading to resistance to third-generation cephalosporins. Other pathogens, such as Neisseria species and Staphylococcus aureus in some contexts, may also exhibit cephalosporin resistance. The presence of cephalosporinresistant organisms often necessitates alternative therapies, frequently guided by local susceptibility patterns and stewardship programs.

Diagnosis relies on standardized susceptibility testing with interpretive breakpoints from bodies such as CLSI and EUCAST. Preventive measures emphasize antimicrobial stewardship, infection control, and surveillance to monitor resistance trends and guide empiric therapy.