Pseudomonas aeruginosa Oligoribonuclease Contributes to Tolerance to Ciprofloxacin by Regulating Pyocin Biosynthesis

Abstract

Bacterial oligoribonuclease (Orn) is a conserved 3=-to-5= exonuclease. In Pseudomonas aeruginosa, it has been demonstrated that Orn plays a major role in the hydrolysis of pGpG, which is required for cyclic-di-GMP homeostasis. Meanwhile, Orn is involved in the degradation of nanoRNAs, which can alter global gene expression by serving as transcription initiation primers. Previously, we found that Orn is required for the type III secretion system and pathogenesis of P. aeruginosa, indicating a role of Orn in the bacterial response to environmental stimuli. Here we report that Orn is required for the tolerance of P. aeruginosa to ciprofloxacin. Transcriptome analysis of an orn mutant revealed the upregulation of pyocin biosynthesis genes. Mutation of genes involved in pyocin biosynthesis in the background of an orn mutant restored bacterial tolerance to ciprofloxacin. We further demonstrate that the upregulation of pyocin biosynthesis genes is due to RecA-mediated autoproteolysis of PrtR, which is the major negative regulator of pyocin biosynthesis genes. In addition, the SOS response genes were upregulated in the orn mutant, indicating a DNA damage stress. Therefore, our results revealed a novel role of Orn in bacterial tolerance to ciprofloxacin.

Positivity of ExoU Gene of Type III Secretion System and Fluoroquinolone Resistance of Psedomonas aeruginosa from Sputum of Nosocomial Pneumonia Patients in Sanglah Hospital, Bali

“…That enzyme was conserved in bacteria which has a 3'-5' exonuclease activity that break 2-5-nt RNA (nanoRNA) to mononucleotide. If Orn decreases, there will increase of nanoRNA and cyclic-di-GMP (C-di-GMP) that can decrease expression TTSS P. aeruginosa (Chen et al 2016, Chen et al 2017. C-di-GMP altered the amount of cAMP levels that induce expression of TTSS genes by cAMP reseptor protein Vfr (Chen et al 2016).…”

Pseudomonas aeruginosa Polynucleotide Phosphorylase Contributes to Ciprofloxacin Resistance by Regulating PrtR

“…The bacterial strains, plasmids and primers used in this study were listed in Table 1 (Furste et al, 1986; Hoang et al, 1998; Choi and Schweizer, 2006; Sun et al, 2014; Chen et al, 2016, 2017). All bacterial strains were cultured in Luria–Bertani (LB) broth (5 g/L Nacl, 5 g/L yeast extract and 10 g/L tryptone, pH 7.4) at 37 ∘ C with agitation at 200 rpm.…”

“…P. aeruginosa encodes multiple resistant determinants against fluoroquinolone antibiotics, such as multidrug efflux systems and pyocyanin (Subedi et al, 2018; Fan et al, 2019). However, chromosomally encoded pyocin biosynthesis genes increase the bacterial susceptibility to fluoroquinolone antibiotics (Brazas and Hancock, 2005; Sun et al, 2014; Chen et al, 2017). Ninety percent of P. aeruginosa strains produce pyocins, and each P. aeruginosa strain usually produces multiple types of the pyocins (Michel-Briand and Baysse, 2002; Ghequire and De Mot, 2014).…”

Oligoribonuclease Contributes to Tolerance to Aminoglycoside and β-Lactam Antibiotics by Regulating KatA in Pseudomonas aeruginosa

“…Previously, we demonstrated that Orn is required for the T3SS gene expression and bacterial virulence in a mouse acute pneumonia model (18). In addition, we demonstrated that Orn contributes to bacterial resistance to ciprofloxacin by influencing pyocin biosynthesis (19). However, whether Orn is involved in bacterial tolerance to other categories of antibiotics remains unknown.…”