Identification of a novel ciprofloxacin tolerance gene, < em > aciT, < /em > which contributes to filamentation in < em > Acinetobacter baumannii < /em >

Antimicrob Agents Chemother. 2021 Apr 5:AAC.01400-20. doi: 10.1128/AAC.01400-20. Online ahead of print.ABSTRACTFluoroquinolones are one of the most prescribed broad-spectrum antibiotics. However, their effectiveness is being compromised by high rates of resistance in clinically important organisms including Acinetobacter baumannii We sought to investigate the transcriptomic and proteomic responses of the clinical A. baumannii strain AB5075-UW upon exposure to sub-inhibitory concentrations of ciprofloxacin. Our transcriptomics and proteomics analysis found that the most highly expressed genes and proteins were components of the intact prophage, phiOXA. The next most highly expressed gene and protein under ciprofloxacin stress was a hypothetical gene ABUW_0098, named here as Acinetobacter ciprofloxacin tolerance (aciT) gene. Disruption of this gene resulted in higher susceptibility to ciprofloxacin, and complementation of the mutant with a cloned aciT gene restored ciprofloxacin tolerance to parental strain levels. Microscopy studies revealed, that aciT is essential for filamentation during ciprofloxacin stress in A. baumannii Sequence analysis of aciT indicate the encoded protein is likely to be localised to the cell membrane. Orthologs of aciT are found widely in the genomes of species from the Moraxellaceae family and are well conserved in Acinetobacter species, suggesting an important role. Taken together, this study has identified a new gene conferring tolerance to ciprofl...
Source: Antimicrobial Agents and Chemotherapy - Category: Microbiology Authors: Source Type: research