Multiple Low-Reactivity Class B Penicillin-Binding Proteins Are Required for Cephalosporin Resistance in Enterococci

Enterococcus faecalisand Enterococcus faeciumare commensals of the gastrointestinal tract of most terrestrial organisms, including humans, and are major causes of health care-associated infections. Such infections are difficult or impossible to treat, as the enterococcal strains responsible are often resistant to multiple antibiotics. One intrinsic resistance trait that is conserved among E. faecalisand E. faeciumis cephalosporin resistance, and prior exposure to cephalosporins is one of the most well-known risk factors for acquisition of an enterococcal infection.