Construction of Actinobacillus pleuropneumoniae-Escherichia coli shuttle vectors: expression of antibiotic-resistance genes

We constructed several cloning vectors, designated pGZRS-18/19 and pGZRS-38/39, which were based on an endogenous Actinobacillus pleuropneumoniae (Apl) 4.3-kb plasmid. They carry the lacZα-complementation fragment and MCS from pUC18/19, and either the bla gene under the control of a putative Apl promoter or the Km R gene from Tn903. These vectors replicate in representative strains of Apl serotypes 1 and 7, Escherichia coli, Pasteurella haemolytica (Ph) and Haemophilus (Actinobacillus) actinomycetemcomitans. We also found that Apl and Ph did not express genes under the control of the lacZ or bla promoters, suggesting that their RNA polymerases may not utilize these promoters.