Km and Tc have similar target regions, and they inhibit protein synthesis by binding to the 30S subunit of the ribosome. Our transcriptomic data showed that Km and Tc markedly induced fimbriae/pili-related genes. Interestingly, these antibiotics also upregulated the natural competence-associated type-IV pilus-assembly proteins encoded by AOLE_15230 and AOLE_17785. Fluoroquinolones can induce the SOS response, key regulators of which are the proteins Lex A and Rec A. However, the lack of a Lex A homolog indicates a critical role of other regulators for SOS response in Acinetobacter species. Here, transcriptome analysis demonstrated that in DR1 cells, Nor strongly induced genes involved in the typical SOS response and DNA-repair genes. The relative amounts of SOS gene expression are determined primarily through by transcriptional regulation. Our previous study showed that, Nor treatment caused target-gene mutation in gyr A and persister formation in DR1. Our data additionally validated the SOS response of Acinetobacter species by showing that DNA damage enhanced mutation frequency. This characteristic of DR1 might be helpful for having resistance to antibiotics stress. Noncoding RNAs are commonly Sulfacetamide Sodium referred to as small RNAs because they are 50�C500 nucleotides in size. Small RNAs are potent regulatory molecules that function at the transcriptional or posttranscriptional level. Interestingly, RNA-seq mapping data revealed that the noncoding regions of DR1 Tenatoprazole contain sequences of small-RNA candidates. Three small RNA candidates are conserved in certain Acinetobacter species. The Northern blot analysis confirmed the expression of small RNA candidates. In a recent study on A. baumannii, 31 putative small RNAs were identified using computational approaches. Two of these small RNAs display sequence similarities with those of the DR1 strain and other Acinetobacter species. However, these 2 small RNAs were not induced under our tested conditions. Small RNAs play key roles in efflux-pump regulation and antimicrobial-agent resistance in A. baumannii, and efflux pumps are widely accepted to bestow clinically relevant resistance to antibiotics.