TABLE 1.

Bacterial strains, plasmids, and primers used in this study

Strain, plasmid, or primerCharacteristic(s)Source or reference
Strains
    E. coli β2155thrB1004 pro thi strA hsdS lacZΔM15 (F′ lacZΔM15 laqIq traD36 proA+ proB+) ΔdapA::erm (Ermr) recA::RPA-2-tet (Tcr)::Mu-Km (Kmr) λpir8
    E. coli TOP10F mcrA Δ(mrr-hsdRMS-mcrBC) φ80lacZΔM15 ΔlacX74 rec A1 deoR araD139 Δ(ara leu)7697 galU galK rpsL (Strr) endA1 nupGTOPO TA cloning; Invitrogen
    S. enterica serovar Typhimurium 421/125S. enterica subsp. enterica serovar Typhimurium live vaccine strain present in the licensed vaccine SalmoporcIDT, Dessau-Tornau, Germany
    S. enterica serovar Typhimurium 421/125ΔompDUnmarked ompD-negative knockout mutant of S. enterica serovar Typhimurium 421/125This work
    S. enterica serovar Typhimurium DT104 27/96S. enterica serovar Typhimurium field isolate carrying phage type DT104 with Ampr Clinr Eryr Penr Tetr44
Plasmids
    pROCKB28.9-kb transconjugation vector based on pROKB1 with oriR6K and mobRP4, Apr Kmr, polycloning site, sacBThis work
    pSOM14666Transconjugation vector pROCKB2 carrying a truncated version of ompD with oriR6K, mobRP4, Apr Kmr, polycloning site, sacBThis work
    pTOPO 2.1Topoisomerase I-“enhanced” E. coli cloning vector carrying ampicillin and kanamycin resistance determinants as well as a lacZ gene for blue-white selectionTOPO TA cloning; Invitrogen
    pSOM810Vector pTOPO 2.1 carrying PCR product of primers pOMPDKOMP1 and pOMPDKOMP2, starting 516 bp upstream of the ompD start codon and ending 31 bp downstream of the stop codon, for complementation of S. enterica serovar Typhimurium ΔompDThis work
Primers
    oDWST5outa5′-TGC TCTAGA CCC GGA GAA ATT ATC AGC AA-3′ (forward primer containing an XbaI restriction site on the 5′ end situated 974 bp upstream of the ompD start codon)This work
    oDWST5outb5′-GCC GAGCTC AGA GAT TGC CAG AGC GTC AT-3′ (reverse primer containing a SacI restriction site on the 5′ end situated 753 bp downstream of the ompD open reading frame)This work
    oOMPDKO15′-CGTCTCGAAGTTTCATTTTAATAATCCTTAT-3′ (reverse primer with BsmBI restriction recognition site on 5′ end situated 9 bp downstream of the ompD start codon; reverse primer to oDWST5_outa for amplification of the upstream DNA fragment used to construct a truncated ompD)This work
    oOMPDKO25′-CGTCTCGACTTCTGAACTACCAGTTCTAATT-3′ (forward primer with BsmBI restriction recognition site on 5′ end situated 2 bp downstream of the ompD stop codon; forward primer to oDWST5_outb for amplification of the downstream DNA-fragment used to construct a truncated ompD)This work
    oOMPD15′-CCATACCAGGATTGCGCTG-3′ (forward primer situated 393 bp upstream of the ompD start codon)This work
    oOMPD25′-CGGTAAGCCGAAACCACAG-3′ (reverse primer situated 317 bp downstream of the ompD open reading frame)This work
    oOMPDKOMP15′-GGCGGGCCGATATTGATATT-3′ (forward primer for complementation of S. enterica serovar Typhimurium ΔompD situated 516 bp upstream of the ompD start codon; the 516-bp nucleotide sequence was also analyzed for promoters using the Web-based program BPROM [www.softberry.com] to ensure that the promoter of the ompD gene was included)This work
    oOMPDKOMP25′-GGACTGGCTTTGTATTCAGAC-3′ (reverse primer for complementation of S. enterica serovar Typhimurium ΔompD situated 31 bp downstream of the ompD stop codon)This work