<p>Mutations in <em>gyrB</em> play an important role in ciprofloxacin-resistant <em>Pseudomonas aeruginosa</em></p>

Abstract

PurposeTo investigate the main molecular resistance mechanisms to fluoroquinolones (FQs) in Pseudomonas aeruginosa and also to investigate the effect of time and concentration on mutations in resistance genes.Materials and methodsThe clinical isolates of P. aeruginosa which are sensitive to ciprofloxacin (CIP) or levofloxacin (LEV) were collected. The isolates were incubated with different concentrations of CIP or LEV for 5 days and the minimal inhibitory concentrations (MICs) of CIP, LEV and ofloxacin (OFX) were measured. The MIC of FQs to P. aeruginosa was measured by the agar dilution method. FQ resistance determining regions of gyrA, gyrB, parC and parE were amplified by PCR, and mutations in four genes were explored using sequence analysis with the Snapgene software. The relative expression levels of two efflux pumps genes (mexA and mexE) were measured by quantitative reverse transcription PCR.ResultsA total of eleven isolates were collected from the Second Hospital of Shanxi Medical University. Amino acid alterations in gyrA and gyrB were mainly detected in resistant mutants, and the percentage of strains with amino acid alterations in gyrB was significantly higher than that in gyrA (P<0.001). MICs of strains with mutations both in gyrA and gyrB were not significantly higher than those of strains with mutations only in gyrB (P>0.05). No amino acid alterations were detected in genes of parC and parE. In both gyrA and gyrB, the number of amino acid alterations increased with incubation time prolonged and increased with increasing incubation concentration.ConclusionCIP was more competent than LEV in making P. aeruginosa resistant to in vitro selection. Mutations occurring in gyrB played an important role in FQ resistance of P. aeruginosa in vitro selection.

NtrBC Selectively Regulates Host-Pathogen Interactions, Virulence, and Ciprofloxacin Susceptibility of Pseudomonas aeruginosa

“…However, ciprofloxacin resistance is on the rise, with 40% of CF isolates sampled in one study exhibiting resistance ( Landman et al., 2007 ). Ciprofloxacin resistance is usually multifactorial, involving expulsion by the multidrug efflux-porin systems ( Rehman et al., 2019 ), as well as target site mutation in the DNA gyrase ( gyrAB ) or topoisomerase ( parCE ) that are targeted by ciprofloxacin ( Feng et al., 2019 ). We identified other, non-canonical effectors of ciprofloxacin resistance downstream of NtrBC that spanned multiple physiological categories ( Table 1 ).…”

Mechanisms for Development of Ciprofloxacin Resistance in a Clinical Isolate of Pseudomonas aeruginosa

“…The mechanisms of ciprofloxacin resistance in P. aeruginosa are usually multifactorial, which include the following: (i) mutation of ciprofloxacin target-encoding genes gyrAB (encoding DNA gyrase) or/and parCE (encoding topoisomerase; Lee et al, 2005 ; Feng et al, 2019 ); (ii) overexpression of efflux pump encoding genes to increase the expulsion of ciprofloxacin from P. aeruginosa cells, including mexEF-oprN , mexAB-oprM , mexXY , and mexCD-oprJ ( Kohler et al, 1997 ; Masuda et al, 2000 ; Rehman et al, 2019 ); and (iii) acquisition of ciprofloxacin-resistant genes through horizontal gene transfer ( Chavez-Jacobo et al, 2018 ; Liu et al, 2018 ). Although these and other studies have associated the mechanisms of ciprofloxacin resistance among clinical P. aeruginosa strains, there is little information about the molecular details resulting in the evolutionary dynamics of clinical isolates of P. aeruginosa from ciprofloxacin susceptible to resistant, as well as the relative quantitative contribution of each of the resistant mechanisms mentioned above.…”

Multidrug-Resistant Bacteria Isolated From Surgical Site of Dogs, Surgeon's Hands and Operating Room in a Veterinary Teaching Hospital in Brazil

“…This drug is usually used to treat serious infections caused by enterobacteria strains and Pseudomonas spp. in veterinary medicine (Papich 2013;Feng et al 2019;Pang et al 2019). Your empiric administration could contribute to the resistance to other antimicrobials of the same class used to treat human infections, as cipro oxacin (Barrasa et al 2000;Papich 2013).…”