Table 1 Bacterial strains and plasmids used in this study

S. enterica serovar Typhimurium strains

χ3761

Wild type S. Typhimurium, UK-1

[65]

SW121

ΔrfbP ΔfliC ΔfljB

Lab stock

SW122

ΔrfbP ΔfliC ΔfljB ΔpagP81

This study

SW123

ΔrfbP ΔfliC ΔfljB ΔpagP81::P_lpplpxE

This study

SW124

ΔrfbP ΔfliC ΔfljB ΔpagP81::P_lpplpxE ΔtolR

This study

SW125

ΔrfbP ΔfliC ΔfljB ΔpagP81::P_lpplpxE ΔtolR Δasd

This study

E. colistrains

χ7232

endA1 hsdR17 (r_K-, m_k+) glnV44 thi-1 recA1 gyrA relA1 ∆(lacZYA-argF)U169 λpir deoR (φ80dlac ∆(lacZ)M15)

[66]

χ7213

thi-1 thr-1 leuB6 glnV44 fhuA21 lacY1 recA1 RP4-2-Tc::Mu[λ pir] ∆asdA4 ∆(zhf-2::Tn10)

[66]

G7572

Wild type E. coli O111:H8, which was isolated from human faeces and are resistant to streptomycin

Lab collection

G2734

Wild type E. coli O157:H7, which was isolated from human faeces and are resistant to streptomycin

Lab collection

G1652

Wild type E. coli O26:H46, which was isolated from human faeces

Lab collection

G2511

Wild type E. coli O45:K1:H10, which was isolated from human faeces

Lab collection

G1442

Wild type E. coli O103, which was isolated from human faeces

Lab collection

G1345

Wild type E. coli O145, which was isolated from human faeces

Lab collection

Suicide and cloning vectors

pYA4278

sacB mobRP4 R6K ori Cm⁺, derived from pRE112

[24]

pYA4288

pagP8 deletion

[17]

pYA4295

∆pagP deletion, and P_lpplpxE insertion

[17]

pSS021

for Δasd mutation, suicide plasmid

[30]

pSS264

for ∆tolR mutation, suicide plasmid

This study

Recombinant plasmids

pSW047

Asd⁺ vector, pSC101 ori, P_trc promoter, the same strain as pG8R184

[29]

pSW048

p15a ori, cat, P_lpp promoter

Lab collection

pSW049

pSW047 vector carrying genes involved in the biosynthesis of E. coli O111 O-antigen (wbdH-wbdI fused with wbdJ-wbdM)

This study

pSW050

pSW048 vector carrying genes involved in the biosynthesis of E. coli O157 O-antigen (wbdN-wbdQ fused with wbdR, and gne)

This study

pSW051

pSW047 vector carrying genes involved in the biosynthesis of E. coli O26 O-antigen (wxz-wbuC)

This study

pSW052

pSW048 vector carrying genes involved in the biosynthesis of E. coli O45 O-antigen (wbhP-wbhS fused with tII-wbhW)

This study

pSW053

pSW047 vector carrying genes involved in the biosynthesis of E. coli O145 O-antigen (wckD-wbuC)

This study

pSW054

pSW048 vector carrying genes involved in the biosynthesis of E. coli O103 O-antigen (wbtA-gne)

This study

Strains for isolating OMV

OMV1

Isolation from SW125 electroplated with pSW049

OMV2

Isolation from SW124 electroplated with pSW050

OMV3

Isolation from SW125 electroplated with pSW049 and pSW050

OMV4

Isolation from SW125 electroplated with pSW051

OMV5

Isolation from SW124 electroplated with pSW052

OMV6

Isolation from SW125 electroplated with pSW051 and pSW052

OMV7

Isolation from SW125 electroplated with pSW053

OMV8

Isolation from SW124 electroplated with pSW054

OMV9

Isolation from SW125 electroplated with pSW053 and pSW054