[Inhibitory activity of dihydroxy-phenyl-propenone on betalactamase of Enterobacter cloacae : preliminary study for drug development to overcome bacterial resistance. ]. / Actividad inhibitoria de dihidroxifenil propenona sobre betalactamasas de Enterobacter cloacae: estudio preliminar en el desarrollo de fármacos para enfrentar la resistencia bacteriana

INTRODUCTION: Enterobacter cloacae is a pathogenic microorganism with the ability to produce betalactamase enzymes, which makes them resistant to betalactamic antibiotics. Additionally, the limited activity of enzymatic inhibitors has been identified, and, therefore, the design of new drugs and the promotion of their rational use are the only possibilities to overcome this problem. OBJECTIVE: The aim of this research was to evaluate the effect of dihydroxy-phenyl-propenone on a clinical isolate of E. cloacae , as well as its activity on a betalactamase isolated from this resistant microorganism in order to contribute to the search for new betalactamase inhibitors. MATERIALS AND METHODS: Dihydroxy-phenyl-propenone chalcone was synthesized and evaluated on a clinical isolate of E. cloacae to determine the minimum inhibitory concentration by broth microdilution; once the betalactamase enzyme was purified by affinity chromatography, a spectrophotometric analysis was done to evaluate its kinetic activity. RESULTS: The minimum inhibitory concentration value of dihydroxy-phenyl-propenone on E. cloacae was 35 µg/ml; the recovery percentage of the betalactamase from the microorganism was 31.75% and the kinetic parameters were V max =1.7 x 10 -3 µM/min and K M = 2330 µM, which show an important inhibitory activity. CONCLUSION: Dihydroxy-phenyl-propenone has shown inhibitory activity on betalactamase enzymes and the ability to protect the chemical integrity of betalactamic antibiotics; this synergistic effect turns it into a promising compound in the search for new alternatives to overcome bacterial resistance.

Actividad inhibitoria de dihidroxifenil propenona sobre betalactamasas de Enterobacter cloacae: estudio preliminar en el desarrollo de fármacos para enfrentar la resistencia bacteriana / Inhibitory activity of dihydroxy-phenyl-propenone on betalactamase of Enterobacter cloacae : Preliminary study for drug development to overcome bacterial resistance

Introducción . Los microorganismos patógenos como Enterobacter cloacae producen betalactamasas que les confieren resistencia frente a los antibióticos betalactámicos; se ha identificado, además, la actividad limitada de los inhibidores enzimáticos, de modo que la única posibilidad de enfrentar la resistencia es el diseño de nuevos fármacos y su uso racional. Objetivo. Evaluar el efecto de la chalcona dihidroxifenil propenona sobre un aislamiento clínico de E. cloacae y sobre la betalactamasa aislada a partir de este microorganismo resistente como un aporte en la búsqueda de compuestos inhibidores de las betalactamasas. Materiales y métodos. Se sintetizó la chalcona dihidroxifenil propenona y se evaluó su efecto sobre el aislamiento clínico de E. cloacae para determinar la concentración inhibitoria mínima mediante el método de microdilución en caldo y con la betalactamasa purificada mediante cromatografía de afinidad se realizaron estudios espectrofotométricos de cinética enzimática. Resultados. La concentración inhibitoria mínima de la dihidroxifenil propenona sobre E. cloacae fue de 35 µg/ml; el porcentaje de recuperación de la betalactamasa a partir del microorganismo fue de 31,75 %; en el estudio cinético se evidenció actividad inhibitoria de acuerdo con los parámetros cinéticos de V max =1,7 x 10 -3 µM/minuto y K M´ =2330 µM. Conclusión. La chalcona dihidroxifenil propenona ejerce su actividad inhibitoria por medio de la interacción con la betalactamasa y, de esta manera, protege la integridad estructural de los antibióticos betalactámicos; dicho efecto sinérgico la convierte en un compuesto promisorio en la búsqueda de alternativas para enfrentar la resistencia bacteriana.

Introduction: Enterobacter cloacae is a pathogenic microorganism with the ability to produce betalactamase enzymes, which makes them resistant to betalactamic antibiotics. Additionally, the limited activity of enzymatic inhibitors has been identified, and, therefore, the design of new drugs and the promotion of their rational use are the only possibilities to overcome this problem. Objective: The aim of this research was to evaluate the effect of dihydroxy-phenyl-propenone on a clinical isolate of E. cloacae , as well as its activity on a betalactamase isolated from this resistant microorganism in order to contribute to the search for new betalactamase inhibitors. Materials and methods: Dihydroxy-phenyl-propenone chalcone was synthesized and evaluated on a clinical isolate of E. cloacae to determine the minimum inhibitory concentration by broth microdilution; once the betalactamase enzyme was purified by affinity chromatography, a spectrophotometric analysis was done to evaluate its kinetic activity. Results: The minimum inhibitory concentration value of dihydroxy-phenyl-propenone on E. cloacae was 35 µg/ml; the recovery percentage of the betalactamase from the microorganism was 31.75% and the kinetic parameters were V max =1.7 x 10 -3 µM/min and K M = 2330 µM, which show an important inhibitory activity. Conclusion: Dihydroxy-phenyl-propenone has shown inhibitory activity on betalactamase enzymes and the ability to protect the chemical integrity of betalactamic antibiotics; this synergistic effect turns it into a promising compound in the search for new alternatives to overcome bacterial resistance.

Screening and isolation of penicillinase inhibitor, KA-107.

It is known that penicillin resistance of bacteria is mainly caused by the inactivation of penicillin by penicillinase derived from such strains. We have developed a screening procedure for penicillinase inhibitors. Several microorganisms were found to produce such inhibitors, and from the culture filtrate of Streptomyces gedanensis ATCC 4880 a penicillinase inhibitor, named KA-107, was isolated. The characteristics of this inhibitor were revealed by an in vitro test by using penicillinase derived from penicillin resistant Staphylococcus aureus, FS-1277. When KA-107 was used in combination with penicillin-G, ampicillin, d- or l-phenethicillin, the growth inhibitory activity of these penicillins was maintained.