Development of In Vitro resistance to fluoroquinolones in Pseudomonas aeruginosa

Abstract

Background: The objectives of this study were to investigate the dynamics of different resistant mechanisms in P.aeruginosa populations that have evolved under fluoroquinolone pressure, and any interactions between these mechanisms in the evolutionary trajectories. Methods:In this study, bacteria of the strain ATCC27853 were selected under different concentrations of levofloxacin and ciprofloxacin for six parallel lineages. The four target genes in the quinolone-resistance determining region were amplified and then Sanger sequencing was used to find the mutations. The expression of four efflux pump proteins were evaluated by real-time PCR, using the relative quantitation method, and the ATCC27853 was selected as a control.Results: we found that the P.aeruginosa was killed by ciprofloxacin earlier than levofloxacin. We found five different mutations in three subunits of QRDRs in our study; gyrA was the main mutated gene for conferring resistance to fluoroquinolone. A greater number of mutations appeared at 4mg/L for levofloxacin and at 2mg/L for ciprofloxacin. The main efflux pump that was expressed was MexCD-OprJ, and the first over expressed was evident at 0.5mg/L for levofloxacin and 0.25mg/L for ciprofloxacin. Conclusions:The mutation of gyrA 83 and overexpression of MexCD-OprJ were the main mechanisms that conferred resistance of P.aeruginosa to levofloxacin and ciprofloxacin. Ciprofloxacin had a stronger ability to kill the bacteria, while may render bacteria more susceptible to resistance. Background:Pseudomonas aeruginosa (P.aeruginosa) is a Gram-negative opportunistic human pathogen that can cause patients suffering from cystic fibrosis (CF) to become immune-compromised, occasionally leading to death [1]. Fluoroquinolones (FQ), which have favorable pharmacokinetic/pharmacodynamic properties are one of the major classes of antibiotics used in the treatment of infections caused by P.aeruginosa. P.aeruginosa has a large variety of available resistance mechanisms, and these may act in combination, rendering even the most potent agents useless [2].The most prevalent mechanisms contributing to FQ resistance in P.aeruginosa involve mutations in the quinolone-resistance determining regions (QRDRs), for example, gyrA and gyrB in DNA gyrase and

Activity of Antimicrobial Peptides and Ciprofloxacin against Pseudomonas aeruginosa Biofilms

“…P. aeruginosa 6294, 6206, Paer1, ATCC 19660 were screened for their ability to develop resistance against AMPs and ciprofloxacin at sub-MIC (one-fold below the MIC), but did not develop resistance (data not shown). P. aeruginosa ATCC 27853 has previously been used to examine its susceptibility to a variety of antimicrobial agents [ 47 , 48 , 49 , 50 ], shown to be heteroresistant to colistin [ 51 ], and used to examine the ability of P. aeruginosa to develop resistance to a variety of antimicrobial agents [ 52 , 53 , 54 ]. This strain’s ability to develop resistance against AMPs and ciprofloxacin at sub-MICs (one-fold below the MIC) was examined as previously described [ 55 ].…”

Addressing antimicrobial resistance with the IDentif.AI platform: Rapidly optimizing clinically actionable combination therapy regimens against nontuberculous mycobacteria

“…Measures to reduce the occurrence of drug-resistant strains must also be addressed even though treatment compliance is critical to clinical outcomes. More importantly, IDentif.AI-designed combinations all contained LVX, a fluoroquinolone antibiotic that is highly prone to induce drug resistance 59 - 61 . IDentif.AI pinpointed interactions (LVX/MEM and LVX/RFB) both contained LVX and only exhibited mild interactions, which may lead to drug resistance.…”

Antimicrobial resistance in Pseudomonas aeruginosa

“…Several studies have been conducted for the identification of mutations in the QRDR regions, of which the missense mutation is the most prevalent mutation. The study conducted by Zhao et al (2020) has observed that the mutations occurred in clinical isolates with the presence of ciprofloxacin and levofloxacin pressure. Ciprofloxacin pressure showed 3 major mutations occurred in gyrA, (gyrA83 and gyrA87), whereas the varying amino acid substitution was observed in the presence of levofloxacin pressure (gyrA83, gyrB466, parE457) (Zhao et al, 2020).…”

“…The study conducted by Zhao et al (2020) has observed that the mutations occurred in clinical isolates with the presence of ciprofloxacin and levofloxacin pressure. Ciprofloxacin pressure showed 3 major mutations occurred in gyrA, (gyrA83 and gyrA87), whereas the varying amino acid substitution was observed in the presence of levofloxacin pressure (gyrA83, gyrB466, parE457) (Zhao et al, 2020). The results of the other study also showed a similar finding along with the parC mutation (Nouri et al, 2016) and in addition to that, the other 3 mutations occurred at 88, 104 and 121 sites in gyrA; no mutation was seen in gyrB, parE (Khademi et al, 2021).…”