Microbial pathogenesis
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Microbial pathogenesis · Jul 2018
Inhibition of quorum sensing-mediated virulence in Serratia marcescens by Bacillus subtilis R-18.
Serratia marcescens is an opportunistic human pathogen causing various nosocomial infections, most importantly urinary tract infections (UTIs). It exhibits increased resistance towards the conventional antibiotics. This study was aimed to evaluate the anti-virulence effect of a rhizosphere soil bacterium Bacillus subtilis strain R-18 against the uropathogen S. marcescens. ⋯ Fourier transform infrared spectroscopic (FT-IR) analysis revealed the alterations in the cellular components of bacterial cell pellets obtained from B. subtilis R-18 PE extract treated and untreated S. marcescens. The differential gene expression study further validated the downregulation of virulence-associated genes. Characterization of the active principle in B. subtilis R-18 PE extract by gas chromatography-mass spectrometry (GC-MS) analysis showed the presence of multiple compounds with therapeutic values, which could possibly reduce the QS-dependent phenotypes in S. marcescens.
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Microbial pathogenesis · May 2018
Attenuation of quorum sensing regulated virulence and biofilm development in Pseudomonas aeruginosa PAO1 by Diaporthe phaseolorum SSP12.
In recent years, Pseudomonas aeruginosa PAO1 emerged as the significant pathogenic microorganism in majority of the hospital-acquired infections due to its resistance to the conventional antibiotics by virtue of its highly organized quorum sensing and associated biofilm formation. In the present study, quorum sensing attenuation potential of Diaporthe phaseolorum SSP12 extract was investigated against P. aeruginosa PAO1 amply supported by molecular docking studies. D. phaseolorum SSP12 extract significantly inhibited the production of LasI/R mediated LasA protease, LasB elastase and chitinase with 66.52 ± 5.41, 71.26 ± 4.58 and 61.16 ± 4.28% of inhibition respectively at a concentration of 750 μg mL-1. ⋯ The presence of bioactive constituents such as phenyl ethylalcohol, 2, 4-di-tert-butylphenol, fenaclon, 1, 4-phenylenediacetic acid, and benzyl hydrazine in D. phaseolorum SSP12 extract was evident from Gas chromatography-mass spectrophotometric (GC-MS) analysis. From the in silico molecular docking studies, fenaclon and 2, 4-di-tert-butylphenol competitively binds to QS receptors LasR and RhlR and alters the binding of its cognate ligands and modulates the expression of virulence phenotypes. The promising anti quorum sensing efficacy of D. phaseolorum SSP12 extract suggested new avenues for development of anti-infective drugs from fungal derived metabolites to counteract the problems associated with conventional antibiotic therapies.
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Microbial pathogenesis · May 2018
Attenuation of quorum sensing controlled virulence factors and biofilm formation in Pseudomonas aeruginosa by pentacyclic triterpenes, betulin and betulinic acid.
The production of virulence determinants and biofilm formation in numerous pathogens is regulated by the cell-density-dependent phenomenon, Quorum sensing (QS). The QS system in multidrug resistant opportunistic pathogen, P. aeruginosa constitutes of three main regulatory circuits namely Las, Rhl, and Pqs which are closely linked to its pathogenicity and establishment of chronic infections. In spite intensive antibiotic therapy, P. aeruginosa continue to be an important cause of nosocomial infections and also the major cause of mortality in Cystic Fibrosis patients with 80% of the adults suffering from chronic P. aeruginosa infection. ⋯ Based on the in vivo studies, the test compounds notably enhanced the survival of Caenorhabditis elegans infected with P. aeruginosa. Furthermore, molecular docking analysis revealed that BT and BA can act as a strong competitive inhibitor for QS receptors, LasR and RhlR. The findings suggest that BT and BA can serve as potential anti-infectives in the controlling chronic infection of P. aeruginosa.
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Microbial pathogenesis · Apr 2018
Tephrosin attenuates sepsis induced acute lung injury in rats by impeding expression of ICAM-1 and MIP-2.
Acute lung injury (ALI), a devastating form of respiratory infections, is characterized by increased edema, release of cytokines, weakened arterial oxygenation and infiltration of neutrophils and lymphocytes. The objective of the research envisaged was to reveal protective effects of tephrosin (TP) in ALI. In the present investigation, sepsis was triggered in rats by cecal ligation and puncture (CLP) method, and TP was administered intraperitonially. ⋯ In comparison to group D, group E reflected higher magnitude of ICAM-1 and MIP-2 suppression due to administration of higher TP dose. Compared to Group A and B, Group E indicated slightly higher expression of ICAM-1 and MIP-2. The research envisaged thus supports that TP attenuates ICAM-1 and MIP-2 expression in sepsis induced ALI rat model.
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Microbial pathogenesis · Mar 2018
Drug resistance profile and molecular characterization of extended spectrum beta-lactamase (ESβL)-producing Pseudomonas aeruginosa isolated from burn wound infections. Essential oils and their potential for utilization.
Pseudomonas aeruginosa producing extended spectrum β-lactamase (ESβL) enzyme had the ability for antimicrobial resistance mechanisms and its multidrug-resistant (MDR) phenotype, has been increasingly reported as a major clinical concern worldwide. The aim of this study was to (i) characterize ESβL-producing MDR P. aeruginosa isolated from burn wound infections phenotypically and molecularly, (ii) evaluate the antibacterial activity of some essential oils (EOs) against selected ESβL-producing drug resistant P. aeruginosa and (iii) characterize a promising EO. ⋯ The high incidence of drug-resistance in ESβL-producing P. aeruginosa isolated from burn wounds is alarming. As proven in vitro, EOs may represent promising natural alternatives against ESβL-producing PDR or MDR P. aeruginosa isolates.