AUTHOR=Gao Mengdi , Feng Chunlin , Ji Yongan , Shi Yaokai , Shi Weina , Zhang Lei , Liu Shuang , Li Anqi , Zhang Xueya , Li Qiaoling , Lu Junwan , Bao Qiyu , Zhang Hailin 

TITLE=AadA36, a novel chromosomal aminoglycoside nucleotidyltransferase from a clinical isolate of Providencia stuartii

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1035651

DOI=10.3389/fmicb.2022.1035651

ISSN=1664-302X

ABSTRACT=In this study, we characterized a novel chromosome-encoded aminoglycoside nucleotidyltransferase (ANT), AadA36, from the Providencia stuartii strain P14 isolated from the sputum specimen of a burn patient at a hospital in Wenzhou, China. Among the functionally characterized ANTs, AadA36 shared the highest amino acid sequence identity of 51.91% with AadA14. The whole genome of P. stuartii P14 consisted of one chromosome and two plasmids (designated pP14-166 and pP14-114). A total of 19 genes with ≥80% similarity with functionally characterized antimicrobial resistance genes (ARGs) were identified in the whole genome, including aminoglycosidess (aac(2’)-Ia, aph(6)-Id, aph(3'')-Ib, aac(6')-Ib, ant(3'')-IIa, aph(3')-Ia), β-lactams (blaCMY-2 and blaOXA-10) and so on. Antimicrobial susceptibility testing showed that the aadA36 gene conferred specific resistance to spectinomycin and streptomycin, and the minimum inhibitory concentration (MIC) of these antimicrobials increased 128- and 64-fold compared with the control strain. The kinetic parameters of AadA36 were consistent with the MIC data of spectinomycin and streptomycin, with kcat/Km ratios of (1.07±2.23)×104 M-1s-1 and (8.96±1.01)×103 M-1s-1, respectively. Comparative genomic analysis of multidrug resistance regions harbored by the plasmid pP14-166 demonstrated the transmissibility of these resistance genes among different bacterial species. The identification of a novel aminoglycoside resistance gene will help us further understand the complexity of the resistance mechanisms and provide deep insights into the dissemination of resistance genes in the microbial population.