Acinetobacter baumannii is an opportunistic bacterium that takes advantage of patients’ weakened immune systems to cause pneumonia, wound infection and sepsis. A common cause of infection in veterans and other hospital patients (hence its nickname of “Iraqibacter”), multi-drug resistant strains of A. baumannii are on the increase.
In a new PLOS Pathogens study, Edward Geisinger of Tufts University School of Medicine, U.S., and colleagues investigated the role of the BfmRS system. This gene regulation network had been found previously to enable A. baumannii to build a protective capsule around itself in response to attack with antibiotics. But the researchers found that not only does the BfmRS stress response aid antibiotic resistance, it also boosts virulence.
Via a series of experiments, the researchers showed that as well as conferring resistance to a wide variety of drugs, BfmRS enables lethal sepsis in mice. It appears that the BfmRS system controls the expression of genes involved in the construction of the cell envelope and in cell division, helping the bacterium to exert its deadly effects.
The research suggests that BfmRS plays a central coordinating role in enabling A. baumannii both to resist antibiotics and to boost virulence in response to them. The BfmRS system could be an important target in the development of drugs to combat the pathogen.
Research Article: Geisinger E, Mortman NJ, Vargas-Cuebas G, Tai AK, Isberg RR (2018) A global regulatory system links virulence and antibiotic resistance to envelope homeostasis in Acinetobacter baumannii. PLoS Pathog 14(5): e1007030. https://doi.org/10.1371/journal.ppat.1007030
Image Credit: Janice Carr, CDC Public Health image Library CC0