Identification and Characterization of a Novel Aminoglycoside 3''-Nucleotidyltransferase, ANT(3'')-IId, From .

A novel plasmid-encoded aminoglycoside 3''-nucleotidyltransferase ANT(3")-IId, was discovered in strain H7 isolated from a chick on an animal farm in Wenzhou, China. The whole-genome of H7 consisted of one chromosome and five plasmids (pH7-250, pH7-108, pH7-68, pH7-48, and pH7-11). was identified as being encoded on pH7-250, sharing the highest amino acid identity of 50.64% with a function-known resistance gene, (KB849358.1). Susceptibility testing and enzyme kinetic parameter analysis were conducted to determine the function of the aminoglycoside 3"-nucleotidyltransferase. The gene conferred resistance to spectinomycin and streptomycin [the minimum inhibitory concentration (MIC) levels of both increased 16-fold compared with the control strain]. Consistent with the MIC data, kinetic analysis revealed a narrow substrate profile including spectinomycin and streptomycin, with / ratios of 4.99 and 4.45×10M S, respectively. Sequencing analysis revealed that the gene was associated with insertion sequences (IS) element [ΔIS-ΔIS-hp-orf-orf-orf1-], and were identified in plasmids from various species. This study of the novel aminoglycoside 3"-nucleotidyltranferase ANT(3")-IId helps us further understand the functional and sequence characteristics of aminoglycoside 3"-nucleotidyltranferases, highlights the risk of resistance gene transfer among species and suggests that attention should be given to the emergence of new aminoglycoside 3"-nucleotidyltranferase genes.