Molecular Mechanisms, Epidemiology, and Clinical Importance of β-Lactam Resistance in Enterobacteriaceae

Despite being members of gut microbiota, Enterobacteriaceae are associated with many severe infections such as bloodstream infections. The beta-lactam drugs have been the cornerstone of antibiotic therapy for such infections. However, the overuse of these antibiotics has contributed to select beta-lactam-resistant Enterobacteriaceae isolates, so that beta-lactam resistance is nowadays a major concern worldwide. The production of enzymes that inactivate beta-lactams, mainly extended-spectrum beta-lactamases and carbapenemases, can confer multidrug resistance patterns that seriously compromise therapeutic options. Further, beta-lactam resistance may result in increases in the drug toxicity, mortality, and healthcare costs associated with Enterobacteriaceae infections. Here, we summarize the updated evidence about the molecular mechanisms and epidemiology of beta-lactamase-mediated beta-lactam resistance in Enterobacteriaceae, and their potential impact on clinical outcomes of beta-lactam-resistant Enterobacteriaceae infections.