Table 1 Bacterial strains and plasmids used in this study

Strains

E. coli DH5α

F^-, Ф80d lacZ∆M15, ∆(lacZYA-argF)U169, endA 1, recA 1, hsdR 17(rk^-, mk⁺) deoR, thi-1, supE 44, λ^-, gyrA 96(Nal^r), relA 1

Invitrogen

E. coli SM10(λ pir)

thi thr leu tonA lacY supE recA::RP4-2-TC::Mu Km λpir

[23]

L. hongkongensis HLHK1 to HLHK30

Thirty human strains isolated from patients with community-acquired gastroenteritis in Hong Kong

[3]

HLHK9

HLHK9 derivative with Sm resistance phenotype, Sm⁺

This study

HLHK9∆ureA

HLHK9 derivative with ureA deletion, Sm⁺

This study

HLHK9∆ureC

HLHK9 derivative with ureC deletion, Sm⁺

This study

HLHK9∆ureD

HLHK9 derivative with ureD deletion, Sm⁺

This study

HLHK9∆ureE

HLHK9 derivative with ureE deletion, Sm⁺

This study

HLHK9∆arcA1

HLHK9 derivative with arcA1 deletion, Sm⁺

This study

HLHK9∆arcA2

HLHK9 derivative with arcA2 deletion, Sm⁺

This study

HLHK9∆arcA1/arcA2

HLHK9 derivative with arcA1 and arcA2 double deletion, Sm⁺

This study

HLHK9∆ureA/arcA1/arcA2

HLHK9 derivative with ureA, arcA1 and arcA2 triple deletion, Sm⁺

This study

Plasmids

pUC19

Cloning vector; ori lacZ Amp^r

Invitrogen

pCVD442

Suicide plasmid; R6K ori mob RP4 bla sacB

[25]

pDS132

Suicide plasmid; R6K ori mob RP4 cat sacB

[22]

pDS132-ureA

pDS132 carrying 5′- and 3′-flanking regions of ureA for mutagenesis of ureA

This study