AmpC β-lactamase among Enterobacteriaceae: A new insight

Abstract

Enterobacteriaceae is one of the most important causes of critical nosocomial and community-onset bacterial infections. In recent decades, the spread of resistance to β-lactam antibiotics has increased among the Enterobacteriaceae due to the different mechanisms such as AmpC beta-lactamase. This study reviews the mechanism of resistance via AmpC, available identification methods of AmpC enzymes, worldwide epidemiology of AmpC producing Enterobacteriaceae, reported risk factors of AmpC, and the last options for antimicrobial treatment. The genes encoding cephalosporinase are commonly located on the chromosomes of some Enterobacteriaceae such as Entrobacter spp. Resistance to broad-spectrum cephalosporins among some species such as Escherichia coli has emerged through the acquisition plasmid-mediated AmpC β-lactamase. The frequency and rapid spread of acquired plasmid-mediated AmpC β-lactamases are increasing among Enterobacteriaceae in the world and lead to many diagnostic and therapeutic challenges for healthcare staffs. One of the most important risk factors for infection with AmpC-producing Enterobacteriaceae is a previous antimicrobial exposure. Infections caused by resistant Enterobacteriaceae due to AmpC have increased the morbidity and mortality rate compared with those caused by susceptible Enterobacteriaceae. The first line treatment of infections caused by these bacteria is carbapenem, and alternative drugs are including cefepime, cefpirome, temocillin, tigecycline, fluoroquinolones, cotrimoxazole, colistin, and fosfomycin. The other drugs are currently under-researched.