Carbapenem-Resistant, Gram-Negative Bacilli: The State of the Art

The evolution of antimicrobial resistance in bacteria is a complex and longstanding process that has gathered much attention by outpacing the discovery and development of new antibiotics. Among Gram-negative bacilli, resistance has been progressive and unremitting in Enterobacteriaceae, Pseudomonas aeruginosa , and Acinetobacter baumannii . In particular, the spread of carbapenem-resistant, Gram-negative bacilli during the last decade has escalated worldwide, resulting in severe infections, some of which respond to only a few therapeutic options. Often viewed as last-resort antibiotics, carbapenems are rendered inactive against bacteria via the production of carbapenem-hydrolyzing enzymes, utilization of impermeable cell wall porins, active expulsion of carbapenem molecules by efflux pumps, production of mutant penicillin-binding proteins, or a combination. This chapter describes the mechanisms and epidemiology of resistance to carbapenems in Gram-negative pathogens. It also sheds a light on laboratory detection of these pathogens and presents available control and therapeutic options for their containment.