Estudio del efecto sinérgico de la combinación de amoxicilina y ciprofloxacina frente a Pseudomona aeruginosa multirresistente

Abstract

The objective of the present study was to evaluate the synergistic effect of the combination of amoxicillin and ciprofloxacin against a multidrug-resistant P. aeruginosa strain. An exploratory, descriptive, and observational in vitro experimental study was conducted in which a multidrug-resistant P. aeruginosa strain donated by INSPI was analyzed. It was worked with 8 serial dilutions for each antibiotic; for amoxicillin (2ug/mL to 256 ug/mL) and for ciprofloxacin (0.50 ug/mL to 64 ug/mL) by the microdilution in broth method using the chessboard assay. As a result, a minimum inhibitory concentration (MIC) of 65 ug/mL was obtained for amoxicillin, and for ciprofloxacin the MIC was 16 ug/mL, while the MIC of the combination between amoxicillin and ciprofloxacin was 16/4 ug/mL respectively. In addition, the fractional inhibitory concentration (FIC) was calculated where a value of 0.062 was obtained. Being the first in vitro study to perform this combination, it was demonstrated that there is a synergistic effect when combining amoxicillin and ciprofloxacin against a multidrug-resistant P. aeruginosa strain. It was concluded that the increasing prevalence of infections caused by Pseudomonas aeruginosa is one of the main causes of the reduction of antimicrobial therapeutic alternatives by the multiple mechanisms of resistance and the combination of antibiotics has become an alternative of great relevance for its treatment. It is recommended to perform more biological and technical replications of this combination with a greater number of strains of Pseudomonas aeruginosa obtained directly from cultures of those patients who present nosocomial infections.