Iron-dependent mechanisms in Acinetobacter baumannii: pathogenicity and resistance

Acinetobacter baumannii is a Gram-negative opportunistic pathogen that poses a significant challenge in healthcare settings, particularly in ICUs, due to its MDR and high mortality rates, especially among critically ill coronavirus disease 2019 patients. Iron is crucial for the survival, growth and pathogenicity of A. baumannii, and the bacterium has developed multiple iron acquisition systems, including siderophore production, haem uptake and TonB-dependent transport mechanisms, to adapt to the iron-limited environment within the host. Although specific studies on A. baumannii are limited, mechanisms from other bacterial species suggest that similar iron acquisition strategies may play a key role in its virulence. Therapeutic approaches targeting these iron-dependent systems, such as the siderophore-conjugated cephalosporin cefiderocol, have shown potential in overcoming MDR A. baumannii infections. Additionally, strategies such as synthetic siderophores, TonB receptor inhibitors and iron chelators are under investigation to enhance treatment outcomes. Future research should prioritize validating these mechanisms in A. baumannii, advancing clinical trials for these therapies and exploring combination treatments to mitigate resistance and improve clinical outcomes in severely affected patients.