Synergism of fused bicyclic 2-aminothiazolyl compounds with polymyxin B against <i>Klebsiella pneumoniae</i>.
Wang R, Hou S, Dong X, Chen D, Shao L, Qian L, Li Z, Xu X.
A series of fused bicyclic 2-aminothiazolyl compounds were synthesized and evaluated for their synergistic effects with polymyxin B (PB) against <i>Klebsiella pneumoniae</i> (SIPI-KPN-1712). Some of the synthesized compounds exhibited synergistic activity. When 4 μg ml<sup>-1</sup> compound <b>B1</b> was combined with PB, it showed potent antibacterial activity, achieving 64-fold reduction of the MIC of PB. Furthermore, compound <b>B1</b> showed prominent synergistic efficacy in both concentration gradient and time-kill curves <i>in vitro</i>. In addition, <b>B1</b> combined with PB also exhibited synergistic and partial synergistic effect against <i>E. coli</i> (ATCC25922 and its clinical isolates), <i>Acinetobacter baumannii</i> (ATCC19606 and its clinical isolates), and <i>Pseudomonas aeruginosa</i> (Pae-1399).