Multidrug-resistant (MDR) and carbapenem-resistant (CR) Gram-negative pathogens are becoming increasingly prevalent around the globe. Polymyxins and tigecycline are among the few antibiotics available to treat infections with these bacteria but little is known about the frequency of their use. We therefore aimed to estimate the parenteral use of these two drugs in Veterans Affairs medical cente...

THE polymyxins are a group of five closely allied antibiotics extracted from the Bacillus polymyxa. In vitro and in the field of general medicine they have been found bactericidal to nearly all Gram-negative bacilli, and the good results obtained in combating Ps. pyocyanea infection of burns by the local application of polymyxin (Jackson and others, 1951) suggested the possibility of using them...

The combination of polymyxin B and rifampin resulted in an additive effect against all 12 clinical isolates of Serratia marcescens examined, including multiple-drug-resistant isolates.

The mcr-1 gene confers resistance to the polymyxins, including the antibiotic colistin, a medication of last resort for multidrug-resistant infections. The mcr-1 gene was first reported in 2015 in food, animal, and patient isolates from China (1) and is notable for being the first plasmid-mediated colistin resistance mechanism to be identified. Plasmids can be transferred between bacteria, pote...

Polymyxin B nonapeptide, prepared by enzymic removal of the fatty acyl diaminobutyric acid side chain from polymyxin B, was about 100-fold less toxic to K562 cells than polymyxin B. MICs of polymyxin B nonapeptide against a test panel of bacteria were 2- to 64-fold lower than those of polymyxin B.