Multidrug-resistant organism (MDRO)

A multidrug-resistant organism (MDRO) is a microorganism, primarily a bacterium, that exhibits resistance to one or more classes of antimicrobial agents (CDC, 2024). These pathogens, including Methicillin-resistant Staphylococcus aureus (MRSA) and Carbapenem-resistant Enterobacteriaceae (CRE), often emerge in healthcare settings due to selective pressure from antibiotic use (StatPearls, 2023). An MDRO employs diverse resistance mechanisms such as the production of neutralizing enzymes like carbapenemases, the use of efflux pumps to expel drugs, and the modification of drug targets to prevent binding (WHO, 2023). Because the term MDRO represents a broad category of pathogens rather than a single molecular entity, it is not considered a specific therapeutic target; instead, drug development focuses on specific enzymes or structural components within these organisms (NIH, 2022). The prevalence of these organisms is a major global health threat, associated with higher rates of treatment failure, prolonged hospitalizations, and increased mortality (CDC, 2024).

Other names

MDROSuperbugAntimicrobial resistant organismAMR pathogen

Antibacterial agents targeting a multidrug-resistant organism function through various mechanisms including inhibition of cell wall synthesis, inhibition of protein synthesis, or disruption of the cell membrane (StatPearls, 2023). The organism counteracts these through enzymatic inactivation, target modification, or decreased permeability (WHO, 2023).