Superbugs

Superbugs is an informal, non-scientific term used to describe bacteria that are resistant to one or more commonly used antibiotics, making infections harder to treat. The term is imprecise; clinicians prefer terms such as multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) to describe the scope of resistance. MDR strains are resistant to at least one agent in three or more antimicrobial classes; XDR are susceptible to only one or two classes; PDR are resistant to almost all available agents.

Resistance arises mainly through genetic changes in bacteria, including mutations and horizontal gene transfer via plasmids, transposons and integrons. Bacteria can inactivate drugs, alter drug targets, reduce drug accumulation, or bypass the drug’s effect. The spread is accelerated by selective pressure from antibiotic use in human medicine, animal agriculture, poor infection control, and international travel and trade. Substandard dosing and incomplete courses promote survival of resistant strains.

Prominent examples include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae, and carbapenem-resistant Enterobacteriaceae (CRE). Infections with such organisms are associated with higher morbidity, longer hospital stays, and increased mortality, particularly in healthcare settings and in people with weakened immune systems.

Efforts to combat superbugs focus on antibiotic stewardship to optimize antibiotic use, strict infection prevention and control, rapid diagnostics, and surveillance. Research aims to develop new antibiotics, alternative therapies such as bacteriophages or antimicrobial peptides, vaccines, and better vaccination and diagnostics. Global coordination is considered essential due to the cross-border nature of resistance.