GC-MS Profiling and In vitro Antibacterial, Anti-Biofilm and Anti-adhesive Activities of Tamarix ericoides Rottl. Leaf Extract Against Catheter-Associated Urinary Tract Infectious Agents

Catheter-associated urinary tract infection (CAUTI) is one of the most important nosocomial infections among hospitalized patients and causes serious complications due to the development of drug-resistant, biofilms forming strains of microorganisms resulting in treatment challenges. As the chemical catheter-coating agents often fail to prevent biofilm formation, the researchers are looking for compounds of natural origin, and the phytocompounds with multiple modes of action pose as a promising option. Thus, the present study investigated the antibacterial anti-biofilm potentials of the phytocompounds in one of the least explored medicinal plants - Tamarix ericoides Rottl. and its leaf methanolic extract was analyzed against Escherichia coli - one of the most notorious multidrug-resistant, biofilm- forming uropathogens in CAUTIs. The well-diffusion method showed the antibacterial activity of methanolic leaf extract against E. coli and using the microdilution method, the minimal inhibitory concentration (MIC) of the extract against E. coli was calculated as 1 mg/ml. GC-MS profiling of methanolic fractions of T. ericoides showed the presence of eight important phytochemicals such as diethyl phthalate, ethanol, 2-[2-[(2-ethylhexyl)oxy]ethoxy]-, n-hexadecanoic acid, 9-octadecenoic acid, (E)-, 9,12-octadecadien-1-ol, (Z,Z)-octadecanoic acid, -hydroxy-3-(1,1-dimethylprop-2-enyl) coumarin and Cholestan-3,22,26-triol 16-[2- [formylthio]ethyl]- that are responsible for antibacterial activities. The killing kinetics of T. ericoides leaf extract against E. coli showed at 1 h. Further, the antibiofilm activity of T. ericoides leaf extract against E. coli on nonliving surfaces was analyzed and quantified by crystal violet assay. T. ericoides leaf extract reduced mature biofilms of E. coli by 81%, 85%, and 89 % after treatment with 1X MIC (1 mg/ml), 2X MIC (2 mg/ml), and 3X MIC (3mg/ml) concentrations of the extract respectively. This was further confirmed using SEM analysis wherein biofilm reduction was observed when compared to untreated. The catheter coating with T. ericoides leaf extract showed antibacterial activity in the in vitro bladder model and was quantified based on colony count. The CLSM reveals the anti-adhesive property of T. ericoides leaf extract on the catheter surface which reduced the biofilm formation and biofilm thickness when contacted with E. coli cells. Also, 82% of dead cells were observed in the FDA and PI combination. Further, SEM showed the impact of T. ericoides leaf extract on E. coli cell morphology as the cells displayed damage including cell shrinkage. Furthermore, the leaf extract was found to be non-toxic to normal cells. Based on the findings, the authors recommend further investigation to develop T. ericoides leaf extract as a potential catheter coating agent to manage CAUTIs.