Identification and Characterization of a Novel Chromosomal Aminoglycoside 2′-N-Acetyltransferase, AAC(2′)-If, From an Isolate of a Novel Providencia Species, Providencia wenzhouensis R33

• Published in: Frontiers in microbiology 2021-11, Vol.12, p.711037-711037
• Main Authors: Zhou, Kexin, Liang, Jialei, Dong, Xu, Zhang, Peiyao, Feng, Chunlin, Shi, Weina, Gao, Mengdi, Li, Qiaoling, Zhang, Xueya, Lu, Junwan, Lin, Xi, Li, Kewei, Zhang, Hailin, Zhu, Mei, Bao, Qiyu
• Format: Article
• Language: English
• Subjects: AAC(2cpsdummy′); aminoglycoside; kinetic analysis; Microbiology; Providencia; resistance
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2021.711037

Multidrug-resistant bacteria from different sources have been steadily emerging, and an increasing number of resistance mechanisms are being uncovered. In this work, we characterized a novel resistance gene named aac(2′)-If from an isolate of a novel Providencia species, Providencia wenzhouensis R33 (CCTCC AB 2021339). Susceptibility testing and enzyme kinetic parameter analysis were conducted to determine the function of the aminoglycoside 2′- N -acetyltransferase. Whole-genome sequencing and comparative genomic analysis were performed to elucidate the molecular characteristics of the genome and the genetic context of the resistance gene-related sequences. Among the functionally characterized resistance genes, AAC(2′)-If shares the highest amino acid sequence identity of 70.79% with AAC(2′)-Ia. AAC(2′)-If confers resistance to several aminoglycoside antibiotics, showing the highest resistance activity against ribostamycin and neomycin. The recombinant strain harboring aac(2′)-If (pUCP20- aac(2′)-If /DH5α) showed 256- and 128-fold increases in the minimum inhibitory concentration (MIC) levels to ribostamycin and neomycin, respectively, compared with those of the control strains (DH5α and pUCP20/DH5α). The results of the kinetic analysis of AAC(2′)-If were consistent with the MIC results of the cloned aac(2′)-If with the highest catalytic efficiency for ribostamycin ( k cat /K m ratio = [3.72 ± 0.52] × 10 4 M –1 ⋅ s –1 ). Whole-genome sequencing demonstrated that the aac(2′)-If gene was located on the chromosome with a relatively unique genetic environment. Identification of a novel aminoglycoside resistance gene in a strain of a novel Providencia species will help us find ways to elucidate the complexity of resistance mechanisms in the microbial population.