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The synergism between cetrimide and antibiotics against Pseudomonas aeruginosa
Abstract:
Forty eight clinical isolates of P. aeruginosa were tested for susceptibility to seven different antimicrobial agents. When tested on Mueller-Hinton agar, the isolates were found to be resistant to ampicillin, sensitive to the antipseudomonal antibiotics, polymyxin B, gentamicin and carbenicillin. Polymyxin B inhibited all the isolates, whereas both carbenicillin and gentamicin inhibited 92.1% of the isolates. Neomycin, sulphamethoxypyridazine and chlortetracycline showed moderate activity and inhibited 50%, 28.9% and 15.8% of the isolates, respectively. However, on Mueller-Hinton agar supplemented with 0.03% cetrimide, the isolates succumbed readily to antimicrobial agents. In addition to polymyxin B, gentamicin and carbenicillin, all the strains were inhibited by neomycin and 94.7%, 92.1% and 63.6% of the isolates were inhibited by sulphamethoxypyridazine, chlortetracycline and ampicillin, respectively. Cetrimide, in concentrations ranging from 0.01 to 0.04% decreased the MIC of ampicillin against all the isolates, whereas 0.1% and 0.5% polysorbate 80 (tween 80) had no effect on the MIC. Growth inhibition studies have shown that the number of survivors was greatly reduced in presence of cetrimide and ampicillin. There was also an appreciable increase in the uptake of ampicillin by the bacterial cells in the presence of cetrimide.
Insights
Cetrimide enhances the effectiveness of ampicillin against Pseudomonas aeruginosa. This study found cetrimide increased bacterial susceptibility to ampicillin and improved drug uptake.
Area of Science:
- Microbiology
- Bacterial Resistance
- Antimicrobial Agents
Background:
- Pseudomonas aeruginosa is a significant opportunistic pathogen.
- Antimicrobial resistance in P. aeruginosa poses a clinical challenge.
- Understanding factors influencing antimicrobial susceptibility is crucial.
Purpose of the Study:
- To evaluate the antimicrobial susceptibility of clinical P. aeruginosa isolates.
- To investigate the effect of cetrimide on the activity of antimicrobial agents, particularly ampicillin.
- To explore the impact of cetrimide on bacterial cell uptake of ampicillin.
Main Methods:
- Testing susceptibility of 48 P. aeruginosa clinical isolates to seven antimicrobial agents on Mueller-Hinton agar.
- Evaluating antimicrobial activity on Mueller-Hinton agar supplemented with 0.03% cetrimide.
- Assessing the effect of polysorbate 80 (tween 80) on minimum inhibitory concentration (MIC).
- Conducting growth inhibition studies and measuring ampicillin uptake by bacterial cells.
Main Results:
- P. aeruginosa isolates showed resistance to ampicillin but sensitivity to polymyxin B, gentamicin, and carbenicillin on standard agar.
- Cetrimide supplementation significantly increased susceptibility to ampicillin, neomycin, sulphamethoxypyridazine, and chlortetracycline.
- Cetrimide reduced ampicillin's MIC and enhanced ampicillin uptake by bacterial cells.
- Polysorbate 80 had no effect on the MIC.
Conclusions:
- Cetrimide potentiates the activity of ampicillin against P. aeruginosa.
- The presence of cetrimide enhances ampicillin's efficacy by increasing bacterial cell uptake.
- Cetrimide represents a potential adjuvant to overcome ampicillin resistance in P. aeruginosa infections.