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Author (up) Girennavar, B.; Cepeda, M.L.; Soni, K.A.; Vikram, A.; Jesudhasan, P.; Jayaprakasha, G.K.; Pillai, S.D.; Patil, B.S. file  url
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  Title Grapefruit juice and its furocoumarins inhibits autoinducer signaling and biofilm formation in bacteria Type Journal Article
  Year 2008 Publication International Journal of Food Microbiology Abbreviated Journal Int J Food Microbiol  
  Volume 125 Issue 2 Pages 204-208  
  Keywords Analysis of Variance; Beverages; Biofilms/*growth & development; Biomass; Citrus paradisi; Colony Count, Microbial; Escherichia coli O157/drug effects/physiology; Food Contamination/*prevention & control; Food Microbiology; Furocoumarins/isolation & purification/*pharmacology; Gram-Negative Bacteria/drug effects/*physiology; Gram-Positive Bacteria/drug effects/*physiology; Pseudomonas aeruginosa/drug effects/physiology; Quorum Sensing; Salmonella typhimurium/drug effects/physiology; Signal Transduction  
  Abstract Cell-to-cell communications in bacteria mediated by small diffusible molecules termed as autoinducers (AI) are known to influence gene expression and pathogenicity. Oligopeptides and N-acylhomoserine lactones (AHL) are major AI molecules involved in intra-specific communication in gram-positive and gram-negative bacteria respectively, whereas boronated-diester molecules (AI-2) are involved in inter-specific communication among both gram-positive and gram-negative bacteria. Naturally occurring furocoumarins from grapefruit showed >95% inhibition of AI-1 and AI-2 activities based on the Vibrio harveyi based autoinducer bioassay. Grapefruit juice and furocoumarins also inhibited biofilm formation by Escherichia coli O157:H7, Salmonella typhimurium and Pseudomonas aeruginosa. These results suggest that grape fruit juice and furocoumarins could serve as a source to develop bacterial intervention strategies targeting microbial cell signaling processes.  
  Call Number Serial 1579  
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Author (up) Lapenda, J.C.; Silva, P.A.; Vicalvi, M.C.; Sena, K.X.F.R.; Nascimento, S.C. file  url
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  Title Antimicrobial activity of prodigiosin isolated from Serratia marcescens UFPEDA 398 Type Journal Article
  Year 2015 Publication World Journal of Microbiology & Biotechnology Abbreviated Journal World J Microbiol Biotechnol  
  Volume 31 Issue 2 Pages 399-406  
  Keywords Acinetobacter/drug effects; Anti-Bacterial Agents/chemistry/*pharmacology; Bacteria/*drug effects/growth & development; Disk Diffusion Antimicrobial Tests; Enterococcus faecalis/drug effects; Escherichia coli/drug effects; Prodigiosin/chemistry/*pharmacology; Pseudomonas aeruginosa/drug effects; Serratia marcescens/*chemistry; Spectrophotometry; Staphylococcus aureus/drug effects; Streptococcus pyogenes/drug effects  
  Abstract Prodigiosin is an alkaloid and natural red pigment produced by Serratia marcescens. Prodigiosin has antimicrobial, antimalarial and antitumor properties and induces apoptosis in T and B lymphocytes. These properties have piqued the interest of researchers in the fields of medicine, pharmaceutics and different industries. The aim of the present study was to evaluate the antimicrobial activity of prodigiosin against pathogenic micro-organisms. The red pigments produced by S. marcescens exhibited absorption at 534 nm, Rf of 0.59 and molecular weight of 323 m/z. Antimicrobial activity was tested against oxacillin-resistant Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes, Acinetobacter sp. and oxacillin-resistant S. aureus. The standard antibiotics employed were ampicillin, chloramphenicol, gentamicin and oxacillin. The disc-diffusion tests demonstrated significant inhibition zones for S. aureus (35 +/- 0.6), E. faecalis (22 +/- 1.0) and S. pyogenes (14 +/- 0.6). However, prodigiosin showed resistance to E. coli, P. aeruginosa and acinetobacter, where no significant formation of inhibitory halos were observed. We determined the inhibitory minimum concentrations and bactericidal for 20 strains of oxacillin-resistant S. aureus (ORSA). The pattern was the antibiotic oxacillin. The minimum inhibitory concentrations observed ranged from 1, 2 and 4.0 mug/mL, respectively, while the minimum bactericidal concentrations ranged from 2, 4, 8 and 16 mug/mL. The S. marcescens prodigiosin produced by showed bactericidal and bacteriostatic effect showing promising antimicrobial activity and suggesting future studies regarding its applicability in antibiotics therapies directed ORSA.  
  Call Number Serial 1672  
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Author (up) Mah, T.F.; O'Toole, G.A. file  url
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  Title Mechanisms of biofilm resistance to antimicrobial agents Type Journal Article
  Year 2001 Publication Trends in Microbiology Abbreviated Journal Trends Microbiol  
  Volume 9 Issue 1 Pages 34-39  
  Keywords Anti-Bacterial Agents/*pharmacology; Bacterial Proteins/metabolism; Biofilms/*drug effects/growth & development; *Drug Resistance, Microbial; Drug Resistance, Multiple; Klebsiella pneumoniae/drug effects/growth & development/metabolism; Phenotype; Polysaccharides, Bacterial/chemistry/metabolism; Pseudomonas aeruginosa/drug effects/growth & development/metabolism; Sigma Factor/metabolism; Staphylococcus epidermidis/drug effects/growth & development/metabolism  
  Abstract Biofilms are communities of microorganisms attached to a surface. It has become clear that biofilm-grown cells express properties distinct from planktonic cells, one of which is an increased resistance to antimicrobial agents. Recent work has indicated that slow growth and/or induction of an rpoS-mediated stress response could contribute to biocide resistance. The physical and/or chemical structure of exopolysaccharides or other aspects of biofilm architecture could also confer resistance by exclusion of biocides from the bacterial community. Finally, biofilm-grown bacteria might develop a biofilm-specific biocide-resistant phenotype. Owing to the heterogeneous nature of the biofilm, it is likely that there are multiple resistance mechanisms at work within a single community. Recent research has begun to shed light on how and why surface-attached microbial communities develop resistance to antimicrobial agents.  
  Call Number Serial 1538  
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