Interplay between Colistin Resistance, Virulence and Fitness in Acinetobacter baumannii

• Autor(a) principal: Silva, Gabriela Jorge da
• Data de Publicação: 2017
• Outros Autores: Domingues, Sara
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/108096; https://doi.org/10.3390/antibiotics6040028
• topic: Acinetobacter baumannii; colistin; polymyxin; antimicrobial resistance; multidrug resistance; lipopolysaccharide; lipid A; biological cost; virulence; two-component systems

Acinetobacter baumannii is an important opportunistic nosocomial pathogen often resistant to multiple antibiotics classes. Colistin, an "old" antibiotic, is now considered a last-line treatment option for extremely resistant isolates. In the meantime, resistance to colistin has been reported in clinical A. baumannii strains. Colistin is a cationic peptide that disrupts the outer membrane (OM) of Gram-negative bacteria. Colistin resistance is primarily due to post-translational modification or loss of the lipopolysaccharide (LPS) molecules inserted into the outer leaflet of the OM. LPS modification prevents the binding of polymyxin to the bacterial surface and may lead to alterations in bacterial virulence. Antimicrobial pressure drives the evolution of antimicrobial resistance and resistance is often associated with a reduced bacterial fitness. Therefore, the alterations in LPS may induce changes in the fitness of A. baumannii. However, compensatory mutations in clinical A. baumannii may ameliorate the cost of resistance and may play an important role in the dissemination of colistin-resistant A. baumannii isolates. The focus of this review is to summarize the colistin resistance mechanisms, and understand their impact on the fitness and virulence of bacteria and on the dissemination of colistin-resistant A. baumannii strains.