                                        −                      Polymyxin B       0.00 ± 0.00     0.00 ± 0.00   0.00 ± 0.00   Colistin                                        0.00 ± 0.00                                                                     0.00 ± 0.00            **0.00 ± 0.00**                                    *E coli* 