Attenuation of quorum sensing regulated virulence functions and biofilm of pathogenic bacteria by medicinal plant Artemisia annua and its phytoconstituent 1, 8-cineole.

The emergence of multidrug resistance (MDR) in bacterial pathogens is a serious public health concern. A significant therapeutic target for MDR infections is the quorum sensing-regulated bacterial pathogenicity. Determining the anti-quorum sensing abilities of certain medicinal plants against bacterial pathogens as well as the in-silico interactions of particular bioactive phytocompounds with QS and biofilm-associated proteins were the objectives of the present study. In this study, 6 medicinal plants were selected based on their ethnopharmacological usage, screened for Anti-QS activity and Artemisia annua leaf extract (AALE) demonstrated pigment inhibitory activity against Chromobacterium violaceum CV12472. Further, the methanol active fraction significantly inhibited the virulence factors (pyocyanin, pyoverdine, rhamnolipid and swarming motility) of Pseudomonas aeruginosa PAO1 and Serratia marcescens MTCC 97 at respective sub-MICs. The inhibition of biofilm was determined using a microtiter plate test and scanning electron microscopy. Biofilm formation was impaired by 70%, 72% and 74% in P. aeruginosa, C. violaceum and S. marcescens, respectively at 0.5xMIC of the extract. The phytochemical content of the extract was studied using GC-MS and 1, 8-cineole was identified as major bioactive compound. Furthermore, 1, 8-cineole was docked with quorum sensing (QS) proteins (LasI, LasR, CviR, and rhlR) and biofilm proteins (PilY1 and PilT). In silico docking and dynamics simulations studies suggested interactions with QS-receptors CviR', LasI, LasR, and biofilm proteins PilY1, PilT for anti-QS activity. Further, 1, 8-cineole demonstrated 66% and 51% reduction in violacein production and biofilm formation, respectively to validate the findings of computational analysis. Findings of the present investigation suggests that 1, 8-cineole plays a crucial role in the QS and biofilm inhibitory activity demonstrated by Artemisia annua extract. RESEARCH HIGHLIGHTS: Artemisia annua leaf extract (AALE) methanol fraction demonstrated broad-spectrum QS and biofilm inhibition Scanning electron microscopy (SEM) confirmed biofilm inhibition Molecular docking and simulation studies suggested positive interactions of 1,8-cineol with QS-receptors and biofilm proteins.

Seroprevalence and risk factor analysis of brucellosis among dairy farmers in Aligarh region, North India: creating awareness of a neglected disease.

Introduction. Brucellosis, a globally distributed zoonotic disease, is caused by the Gram-negative bacteria known as Brucella. Humans acquire infection through direct contact with the blood, urine and placenta of animals, inhalation of dust or aerosols at infected animal farms, and raw milk and meat intake. This study aimed to assess the prevalence of brucellosis in dairy farmers in and around the Aligarh region of North India, to document various clinical signs and symptoms in Brucella-positive individuals, and to create awareness in dairy farmers concerning brucellosis and ways to prevent it. Methods. This was an observational study that included 125 dairy farmers in and around the Aligarh region. Serum samples were taken from this high-risk group after obtaining informed consent. Further, a pre-designed proforma was used to collect information about their knowledge, attitude and practices (KAP) concerning brucellosis and assess the risk factors for the disease. The Rose Bengal test (RBT), serum agglutination test (SAT) and enzyme-linked immunosorbent assay (ELISA) were performed to detect the seroprevalence of brucellosis. Result.Brucella infection was diagnosed in 64 (51.20 %) cases by indirect ELISA (IgM+IgG), 41 (32.8 %) by RBT and 4 (3.2 %) by SAT. Significant clustering of patients was seen in the 20-55 years age group. The most common symptoms in ELISA IgM-positive patients were joint pain (16.07 %), fatigue (14.28 %), anorexia (12.50 %), weight loss (8.92 %), malaise (5.35 %), undulant fever (3.57 %), night sweats (3.57 %) and headache (1.78 %). The findings of this study indicate that ELISA (IgM+IgG) exhibits great sensitivity as compared to SAT and RBT. KAP was very poor among dairy farmers. Conclusion. In India, Brucella is a frequent but severely underreported illness. ELISA is the most sensitive serological test for diagnosing brucellosis. No potential vaccine has yet been introduced for humans against brucellosis. Thus, it is necessary to impart awareness and sensitize high-risk groups concerning brucellosis.

Antibiofilm and anti-quorum sensing activity of Psidium guajava L. leaf extract: In vitro and in silico approach.

The quorum sensing mechanism relies on the detection and response to chemical signals, termed autoinducers, which regulate the synthesis of virulence factors including toxins, enzymes, and biofilms. Emerging therapeutic strategies for infection control encompass approaches that attenuate quorum-sensing systems. In this study, we evaluated the antibacterial, anti-quorum sensing, and anti-biofilm activities of Psidium guajava L. methanolic leaf extracts (PGME). Minimum Inhibitory Concentrations (MICs) of PGME were determined as 500 µg/ml for C. violaceum and 1000 µg/ml for P. aeruginosa PAO1. Significantly, even at sub-MIC concentrations, PGME exhibited noteworthy anti-quorum sensing properties, as evidenced by concentration-dependent inhibition of pigment production in C. violaceum 12742. Furthermore, PGME effectively suppressed quorum-sensing controlled virulence factors in P. aeruginosa PAO1, including biofilm formation, pyoverdin, pyocyanin, and rhamnolipid production, with concentration-dependent inhibitory effects. Phytochemical analysis utilizing GC-MS revealed the presence of compounds such as alpha-copaene, caryophyllene, and nerolidol. In-silico docking studies indicated a plausible mechanism for the observed anti-quorum sensing activity, involving favorable binding and interactions with QS-receptors, including RhlR, CviR', LasI, and LasR proteins. These interactions were found to potentially disrupt QS pathways through suppression of AHL production and receptor protein blockade. Collectively, our findings propose PGME as a promising candidate for the treatment of bacterial infections. Its attributes that mitigate biofilm development and impede quorum-sensing mechanisms highlight its potential therapeutic value.