Effect of hydro-ethanolic extract of Abelmoschus moschatus against multidrug resistant uropathogenic Escherichia coli biofilm—An insight into antibiofilm therapeutics

Abstract

Uropathogenic Escherichia coli (UPEC) associated with urinary tract infection (UTI) frequently develops biofilms, assisting UPEC persistence and resulting in antimicrobial resistance. Thus, biofilm inhibition is important in UTI treatment. This study investigated the antibiofilm efficacy of the hydro-ethanolic extract of Abelmoschus moschatus (AMHE), a traditional Indian medicinal plant, against multidrug-resistant (MDR) UPEC in vitro. Nine clinical MDR-UPEC and E. coli (ATCC25922) were screened for biofilm production by safranine staining. Water:ethanol (3:7) was used to prepare AMHE. Phytocomponents in AMHE were identified by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-ESI-MS). Minimal inhibitory concentration (MIC) and minimal biofilm inhibitory concentration (MIC-b) of AMHE were determined by spectrophotometry. Growth curve and time-kill kinetics were performed using standard protocols. Metabolic activity and biofilm biomass were determined by MTT assay and confocal laser scanning microscopy. GraphPad Prism v8.0.2 was used for statistical analysis. An array of phytoconstituents in AMHE, including sesquiterpenes, polyphenols, fatty acids, and phytosterols, were identified. All E. coli isolates at 24 and 48 h of static growth exhibited significant biofilm production (p ≤ 0.0001) with cumulative AMHE MIC; 0.8–3.2 mg/ml and MIC-b; 1.6–6.4 mg/ml, respectively. The highest significant (p ≤ 0.0001) reduction in biofilm biomass and metabolic activity at respective 0.5 MIC of AMHE was observed in 3 selected strains without any effect on planktonic growth compared to untreated controls, which suggested its antibiofilm efficacy. Additionally, presence of farnesol, farnesyl acetate, ambrettolide along with other phytoconstituents in AHME might be responsible for the potential antibiofilm attributes. Therefore, future investigations on AMHE might pave the way towards developing effective antibiofilm therapeutics against UPEC biofilm.