Characterization of Chromosome-Mediated Bla(OXA-894) in Shewanella xiamenensis Isolated from Pig Wastewater

A new variant of the bla(OXA-546) gene, namely bla(OXA-894), was identified on the chromosome of Shewanella xiamenensis isolated from pig wastewater in rural China. OXA-894 differs from OXA-546 (A46V, I219del) and OXA-48 (T167I, I219del) with two amino acid substitutions, respectively. The isolate was resistant to ampicillin, aztreonam, imipenem, meropenem and fosfomycin. Carba NP test confirmed S. xiamenensis strain sx20 as a carbapenemase-producer. The bla(OXA-894) gene was located between the gene encoding a LysR family transcriptional regulator and the C15 gene. Its gene environment was similar to other S. xiamenensis with chromosome-located bla(OXA-48)-like genes. The T24H and T94V amino acid substitutions of LuxS protein were predicted to be deleterious, which may affect the virulence phenotype. The occurrence and potential health risk of carbapenem-resistant S. xiamenensis in a water environment is of concern.