A small RNA decreases the sensitivity of Shigella sonnei to norfloxacin

• Published in: BMC research notes Vol. 12; no. 1; pp. 97 - 3
• Main Authors: Gan, I-Ning, Tan, Hock Siew
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 21-02-2019; BioMed Central; BMC
• Subjects: Analysis; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics resistance; Bacillary dysentery; Bacteria; Bacterial Outer Membrane Proteins - drug effects; Data Note; Drug resistance; Drug Resistance, Bacterial; Escherichia coli; Fluoroquinolone; Fluoroquinolones - pharmacology; Gastrointestinal diseases; Gene Expression Regulation, Bacterial - drug effects; Humans; Infection; Medical research; Messenger RNA; Microbial drug resistance; Norfloxacin; Norfloxacin - pharmacology; RNA; RNA, Bacterial - drug effects; RNA, Small Untranslated - drug effects; SdsR; Shigella sonnei; Shigella sonnei - drug effects; Small RNA; Shigella sonnei; Fluoroquinolone; Norfloxacin; Small RNA; Antibiotics resistance; SdsR
• ISSN: 1756-0500; 1756-0500
• DOI: 10.1186/s13104-019-4124-4

Shigella is a human pathogen that causes shigellosis, an acute invasive intestinal infection. Recent studies in the model bacterium Escherichia coli (E. coli) provided evidence that small regulatory RNAs (sRNAs) can contribute to antimicrobial resistance or susceptibility. One of the sRNAs is SdsR, which increases sensitivity of E. coli against fluoroquinolone by repressing the drug efflux pump, TolC. However, no reports exist about the effect of SdsR on fluoroquinolone resistance in Shigella sonnei (S. sonnei). In this study, we established the effect of SdsR on the sensitivity of S. sonnei to norfloxacin.
We tested the effects of SdsR and SdsRv2 on fluoroquinolone resistance in S. sonnei in vivo. SdsRv2 is a synthetic version which promotes higher binding stability to tolC mRNA. Overexpression of either SdsR or SdsRv2 lowers the expression of tolC mRNA. Interestingly, SdsR and SdsRv2 promote the growth of S. sonnei in the presence of a sub-inhibitory concentration of norfloxacin. Mutant carrying SdsRv2 showed the highest growth advantage. This phenotype is opposite to the effect of SdsR reported in E. coli. This study is an example that demonstrates the difference in the phenotypic effect of a highly conserved sRNA in two closely related bacteria.