Multidrug-resistant Gram-negative bacteria-resistant infections: epidemiology, clinical issues and therapeutic options

In the last decade, we have witnessed a dramatic increase in the number of multidrug resistant Gram-negative (MDRGN) bacterial pathogens, both in Italy and worldwide, with Enterobacteriacae (mostly Klebsiella pneumoniae), Pseudomonas aeruginosa and Acinetobacter baumannii being the major threats in clinical practice. Inadequate empirical antimicrobial therapy of severe infections caused by MDR Enterobacteriacae has been associated with an increased morbidity and mortality. However, a careful selection of patients who may receive empirical treatment covering MDR Enterobacteriacae is important to avoid the overuse of broad-spectrum antibiotics. The aim of this review is to describe the mechanism of resistance, epidemiology, risk factors, clinical issues, and therapeutic options for MDRGN pathogens.