Acacia senegal Extract Rejuvenates the Activity of Phenicols on Selected Enterobacteriaceae Multi Drug Resistant Strains

This study reported the phytochemical composition of two hydroethanolic extracts ofAcacia senegalandAcacia seyaltrees from Burkina Faso and their activities, alone or in combination with selected antibiotics, against multidrug resistant bacteria. High performance thin layer chromatography (HPTLC) method was used for phytochemical screening. Total phenolic and total flavonoid ant tannins in leaves extracts contents were assessed by spectrophotometric method. The minimal inhibitory concentrations (MICs) of plant extracts and antibiotics were determined using the microdilution method andp-iodonitrotetrazolium chloride. Combinations of extracts and antibiotics were studied using checkerboard assays. Screening revealed the presence of phenolic compounds, flavonoids, and tannins in the hydroethanolic extract (HE) of the leaves. The HE ofA. seyalshowed the highest total phenolic (571.30 +/- 6.97 mg GAE/g), total flavonoids (140.41 +/- 4.01 mg RTE/g), and tannins (24.72 +/- 0.14%, condensed; 35.77 +/- 0.19%, hydrolysable tannins). However, the HE ofA. senegalshowed the lowest total phenolic (69.84 +/- 3.54 mg GAE/g), total flavonoids (27.32 +/- 0.57 mg RTE/g), and tannins (14.60 +/- 0.01%, condensed; 3.09 +/- 0.02%, hydrolysable). The MICs for HE and antibiotics were in the range of 2-512 and 0.008-1024 mg/L, respectively. All tested HE presented an MIC greater than 512 mg/L except HE ofA. senegal. The lowest MIC value (128 mg/L) was obtained with HE ofA. senegalagainstKlebsiella aerogenesEA298 andEscherichia coliAG100A. Interesting restoring effects on chloramphenicol and florphenicol activity were detected with alcoholic extracts ofA. senegalagainst resistantE. coliandK. aerogenesstrains that overproduce AcrAB or FloR pumps. The adjuvant effect of HE ofA. senegalsuggests that the crude extract of leaves could be a potential source of molecules for improving the susceptibility of bacteria to phenicols antibiotics.