In Vitro Comparison of Antibacterial and Antibiofilm Activities of Selected Fluoroquinolones against Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus

Abstract

An in vitro overview of the inhibitory effects of selected fluoroquinolones against planktonic and biofilm cells of the methicillin-resistant Staphylococcus aureus (MRSA) strain American type culture collection (ATCC) 43300 and the Pseudomonas aeruginosa strain ATCC 27853 was carried out. Biofilm cells of both strains were less susceptible to the selected antibiotics than their planktonic counterparts. In addition, certain antibiotics were more effective against biofilm cells, while others performed better on the planktonic cells. Against P. aeruginosa, ciprofloxacin was the most potent on both planktonic and biofilm cells, whereas ofloxacin was the least potent on both biofilm and planktonic cells. Moxifloxacin and gatifloxacin were the most potent against both planktonic and biofilm MRSA bacteria, however, not in the same order of activity. Norfloxacin was the least active when tested against both planktonic and biofilm cells. The results of this work are expected to provide insight into the efficacy of various fluoroquinolones against MRSA and Pseudomonas aeruginosa biofilms. This study could form the basis for future clinical studies that could recommend special guidelines for the management of infections that are likely to involve bacteria in their biofilm state.

Gold nanoclusters augment a fluoroquinolone lethality against biofilm associated persister cells

“…1b). This finding is consistent with that of Masadeh and collegues who reported a MBEC of 640 μg/mL against 24 h old strain P. aeruginosa (ATCC 27853) biofilm 31 . Contrary to the results for PA01, no eradication of the PA CSOM biofilm was obtained after treatment with ofloxacin at 3000 μg/mL, the concentration in the commercial preparation (FLOXIN®Otic).…”

Understanding Ciprofloxacin Failure in Pseudomonas aeruginosa Biofilm: Persister Cells Survive Matrix Disruption

“…Thus, treating such infections without mechanical biofilm dispersion remains challenging (Mulcahy et al, 2014; Høiby et al, 2015). Among the antibiotics required to treat P. aeruginosa biofilm infections, ciprofloxacin is widely used (Mensa et al, 2018; Masadeh et al, 2019), being the sole oral anti- P. aeruginosa antibiotic, and diffusing in the biofilm deepest layers (Anderl et al, 2000; Walters et al, 2003). Despite these properties, previous studies demonstrated that ciprofloxacin failed to eradicate P. aeruginosa biofilms, even in experimental conditions where no resistant mutants were selected (Spoering and Lewis, 2001; Pamp et al, 2008; Benthall et al, 2015; Pawar et al, 2015).…”

Methods Used for the Eradication of Staphylococcal Biofilms

“…In comparison to MIC determination, these assays are often conducted using flat bottom or modified 96-well plates, called the Calgary device or high-throughput plates (the schematic diagram of both methods is presented in Figure 2) [74,75]. Both assays enable the determination of the minimum biofilm eradication concentration (MBEC) [76,77].…”

“…In comparison to MIC determination, these assays are often conducted using flat bottom or modified 96-well plates, called the Calgary device or high-throughput plates (the schematic diagram of both methods is presented in Figure 2) [74,75]. Both assays enable the determination of the minimum biofilm eradication concentration (MBEC) [76,77]. The ATP bioluminescence (BLM) assay is a method that takes advantage of the measurement of the intracellular concentration of ATP, which correlates with the number of viable bacteria cells and is related to different growth conditions [78].…”