文摘
Our results showed that the mechanisms of resistance to polymyxin B varied significantly between A. baumannii clinical isolates. In contrast to previously reported data, the A027ind strain had acquired simultaneously mutations in both pmrB and lpxA genes after polymyxin B exposure. By transmission electronic microscopy, the exposure to polymyxin B induced a strong condensation and darkening of intracellular material of A. baumannii isolates. The C. elegans assays showed that the A027 strain, which was initially susceptible to polymyxin B, was more virulent than polymixin-resistant A009 strain. However, after polymyxin B exposure, A027ind strain displayed a significant decrease of virulence, which was not observed in the A009ind strain.