Table 1 Strains and plasmids used in this study

Escherichia coli

DH5α

F^-, ϕ80 lacZ ΔM15 Δ(lacZYA-argF) U169 deoR endA1 recA1 hsdR17 (r_K^- m_K⁺) thi-1 glnV44

Laboratory Stock

Burkholderia cenocepacia

K56-2

CF clinical isolate (polymxyin B-resistant)

BCCRC*, [19]

RSF34

K56-2, ΔhldA (polymyxin B-sensitive)

[18]

RSF34 25A

RSF34 colony isolated on 25 μg/ml polymyxin B

This study

RSF34 200E

RSF34 25A colony isolated on 200 μg/ml polymyxin B

This study

RSF34 1000D

RSF34 200E colony isolated on 1 mg/ml polymyxin B

This study

RSF34 4000B

RSF34, selected through multiple rounds for polymyxin B resistance

This study

RSF44

K56-2, ΔfliCD, flagella-negative

[18]

Pseudomonas aeruginosa

PAO1

Non-CF clinical isolate

[56]

Plasmids

pRK2013

RK2 derivative, Km^R mob⁺ tra⁺ ori_colE1

[49]

pSL6

B. cenocepacia expression plasmid, rhamnose-inducible promoter, Tp^R Cm^R

[9]

pSL7

pSL6, B. cenocepacia hldAD

[9]