Isolation of ESBL-producing gram-negative bacteria and in silico inhibition of ESBLs by flavonoids

Objective: To evaluate nosocomial accounts of 426 extended spectrum b-lactamase [ESBL]-producing strains from 705 isolates of 9 pathogenic gram-negative bacteria in vitro. We analysed the genetic divergence of ESBLs by constructing a phylogenetic tree and modelled flavonoid inhibition of ESBLs with in silico molecular docking to determine effective control options

Methods: Nine ESBL-producing bacteria were isolated from urine samples and their antibiograms were determined by the disc-diffusion method. Comparative models of the 9 ESBL enzymes were generated computationally using reference sequences, and validated by Ramachandran plots. Molecular docking with 11 flavonoids was conducted against the ESBL models

Results: Isolated strains were floridly multidrug-resistant. From the docking study, the predicted minimum energy value of amikacin was _8.108 kcal/mol against the wild type TEM-1 ESBL of Acinetobacter baumannii, while the docking value against the mutant type Escherichia coli was _7.388 kcal/mol. The docking scores obtained corroborated the in vitro results showing that the antibiotic was incapable of controlling the ESBL of the mutant strain. Among 11 flavonoids tested against the mutant ESBL of E. coli, epigallocatechin 3-gallate and eriodictyol, with docking scores of _9.448 and _8.161 kcal/ mol, respectively, were the most effective, with druglikeness scores of 0.39 and 1.37, respectively, compared to 1.03 for amikacin

Conclusion: Docking scores and drug-likeness scores indicated that flavonoids are compelling alternative antimicrobial agents that could serve as complementary therapy for newly arising ESBL-producing bacteria

In vitro antibacterial efficacy of plants used by an Indian aboriginal tribe against pathogenic bacteria isolated from clinical samples

Objectives: To evaluate antibacterial efficacies of 21 medicinal plants used by an Indian aboriginal tribe against infectious diseases caused by bacteria isolated from clinical samples

Methods: Standard biochemical procedures were followed for identifying bacteria that were isolated from several clinical samples. All of the bacterial strains were subjected to antibiotic sensitivity tests by Kirby-Bauer's disc diffusion method. From antibiograms of isolated Gram-positive and Gram-negative bacteria, it was discernible that samples were multidrug resistant [MDR]. The methanol leaf-extract of Solanum xanthocarpum was subjected to thin layer chromatography [TLC] for phytochemical analysis. Molecular docking of Beta-lactamase enzyme of Escherichia coli with phytochemicals of S. xanthocarpum was performed to locate effective compounds

Results: The most effective 5 plants, which caused the size of the zone of inhibition to range from 21 to 27 mm, were Buchanania latifolia, Careya arborea, Ocimum tenuiflorum, Senna alata and S. xanthocarpum, for MDR bacteria. S. xanthocarpum had the lowest MIC value of 0.67 mg/ml and the lowest MBC value of 1.51 mg/ml against E. coli. In the TLC study, 9 spots of methanol leaf-extract of S. xanthocarpum were recorded with two solvent systems. The phytochemicals of S. xanthocarpum, solasodine and stigmasterol glucoside had the highest docking score values, -10.868 kcal/mol and ?10.439 kcal/mol, respectively, against Beta-lactamase

Conclusion: This study could prove in vitro antimicrobial efficacy of 5 uncommon plants against MDR pathogenic bacteria. Solasodine and stigmasterol glucoside were computationally recorded as the best controlling chemicals from the plant S. xanthocarpum