Table 1 List of strains and plasmids used in this study

Streptococcus suis

 P1/7

Virulent serotype 2 ST1 strain isolated from a case of pig meningitis in the United Kingdom

[23]

 5P1/7Δlmb

Isogenic mutant derived from P1/7; in frame deletion of lmb gene

[18]

 P1/7 Δlmb/ΔcpsG

Isogenic mutant derived from P1/7; in frame deletion of lmb and cpsG gene

This study

 P1/7 ΔcpsF

Isogenic mutant derived from P1/7; in frame deletion of cpsF

[21]

 P1/7 comp Δlmb

Mutant Δlmb complemented with pMX1-lmb complementation vector

This study

Escherichia coli

 TOP10

F⁻ mrcA Δ(mrr-hsdRMS-mcrBC) φ80 lacZΔM15 ΔlacX74 recA1 araD139 Δ(araleu) 7697 galU galK rpsL (Str^R) endA1 nupG

Invitrogen

 MC1061

Host for pMX1 derivatives

[24]

Plasmids

 pCR2.1

Ap^r, Km^r, pUC ori, lacZΔM15

Invitrogen

 pSET4s

Spc^r, pUC ori, thermosensitive pG + host3 ori, lacZΔM15

[25]

 pMX1

Replication functions of pSSU1, MCS pUC19 lacZ SpR, malX promoter of S. suis, derivative of pSET2

[25, 26]

 p4ΔcpsG

pSET-4 s carrying the construct for lmb allelic replacement

This study

 pMX1-lmb

pMX1 carrying intact lmb gene

This study