Data for A traceless reversible polymeric colistin prodrug to combat multidrug-resistant (MDR) gram-negative bacteria

Due to limited amount of PEG-1, PEG-1 was not filter sterilized. A negative control was included for PEG-1. mPEG-AA and Colistin were filter sterilised through 0.2 μm membrane filter. Remaining stock solutions were stored at room temperature.

All compounds were dissolved in F/S MQH2O. Added 10 μL and 20 μL of 1 mg/mL stock onto a blank disk (Oxoid). Test concentrations Test isolates were matched to a 0.5 McFarland standard before being swabbed onto nutrient agar.

Controls used were: 10μg Colistin and 10μL F/S MQH2O. The sizes of the zones of inhibition are shown in Table 1. The diameter is measured in mm and the zone of inhibition of the disk (6 mm) is included in the ZOI measurement.

Table 1. The size of the zone of inhibition (diameter in mm) of 3 different isolates incubated with 10μg and 20μg of test compound. Pictures taken by ProtoCOL 3 P. aeruginosa ATCC 27853 A. baumannii ATCC 19606 K. pneumoniae ATCC 13883 PEG Compounds: Minimum inhibitory concentration by microbroth dilution – 20150715 HY/JA Stock solutions from DDA were used and diluted in CAMHB according to the tables on page 5 and 6.

PEG-1 was tested up to 16 mg/L due to the limited amount available. PEG-2, mPEG-AA and Colistin were tested up to 128 mg/L. Plates were incubated at 37oC and read at 20hrs incubation. Preparation of medium containing PEG-1, (Adaptation from SOP0028 for lipopeptide MIC screening).

Enough solution for 1x 96 well plates Preparation of medium containing PEG-2, mPEG-AA, Colistin, (Adaptation from SOP0028 for lipopeptide MIC screening). Enough solution for 1x 96 well plates