| dc.description.abstract | Pseudomonas aeruginosa (PA) is a predominant hospital-acquired pathogen which
poses significant challenges in clinical settings due to its resistance to current antibiotic
therapies. Combination therapy is under exploration as a means to enhance the efficacy
of current medications due to limitations in the development of new antibiotics. In this
study, the combination of ceftazidime (Cz) and ciprofloxacin (Ci) was assessed for the
synergistic efficacy of combining Ci and Cz and its potential to reduce the risk of
antibiotic resistance development in PA ATCC 9027. The checkerboard assay was
used to assess the synergy of Ci and Cz by determining fraction inhibitory
concentration (FIC). The effect of Ci on the development of Cz resistance was
investigated via serially exposing PA to the sub-minimal inhibitory concentration
(MIC) values of Cz under the absence or presence of Ci at 0.015625 μg/mL for 14
days. Vice versa, the effect of Cz on the development of Ci resistance was performed
under the absence or presence of Cz 0.125 μg/mL. The Kirby-Bauer disk diffusion
testing was used to determine the antibiotic susceptibility profile of the obtained
strains. Results showed that Ci and Cz had a synergistic effect in inhibiting PA ATCC
9027 (FIC=0.5). In the combination of Ci-Cz0.125, an effect was observed, albeit
insignificant, in reducing resistant development compared to Ci alone. Exposure to Ci
alone promoted resistance to Ci but not to antibiotics from other classes. On the
contrary, Cz-Ci0.015625 delayed the antibiotic resistance development of PA
compared to Cz alone. However, Cz-exposed strains became resistant to Cz as well as
to other β-lactam antibiotics, including cefepime and piperacillin/tazobactam. In
conclusion, the combination of Ci and Cz showed a synergistic effect and delayed
antibiotic resistance development of antibiotic resistance in PA. | en_US |
