title: Therapeutic considerations in the treatment of respiratory infections caused by ceftazidime-resistant Klebsiella pneumoniae.
abstract: Klebsiella pneumoniae are important human pathogens, particularly as causes of nosocomial respiratory tract infections. Intrinsically resistant to ampicillin, in recent years K. pneumoniae strains have acquired resistance to a broad variety of extended-spectrum cephalosporins. This resistance is most commonly mediated by the extended-spectrum beta-lactamases (ESBLs), plasmid-mediated enzymes that have evolved through point mutations in the genes encoding the more susceptible penicillinases TEM-1 and SHV-1. In a small minority of cases, K. pneumoniae have also been found to express extended-spectrum cephalosporin resistance by the elaboration of plasmid-mediated AmpC-type enzymes. These mutant enzymes confer resistance to extended-spectrum cephalosporins, penicillins, and in some cases cefamycins or beta-lactam-beta-lactamase inhibitor combinations. The most reliable and effective antimicrobial treatment of infections caused by these strains are the carbapenems imipenem and meropenem.
authors.affiliation: VA Medical Center and Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA. louis.rice@med.va.gov
authors.forename: L B
authors.initials: LB
authors.lastname: Rice