Strain-Antibiofilm-Activity-e
The Pseudomonas sp. IV2006 culture supernatant (SNIV2006) inhibited Flavobacterium sp. Extracellular polymeric substances without killing the bacteria or inhibiting its growth. Moreover, SNIV2006 had no effect on the Flavobacterium sp. II2003 cell surface hydrophilic/hydrophobic and general Lewis acid-base characteristics, but modified the surface properties of glass, making it on the whole more hydrophilic and more alkaline and significantly reducing bacterial cell adhesion. The glass-coating molecules produced by Pseudomonas sp.
IV2006 were found to probably be polysaccharides, whereas the antibiofilm molecules contained in SNIV2006 and acting during the 2 h adhesion step on glass and polystyrene surfaces would be proteinaceous. Finally, SNIV2006 exhibited a broad spectrum of antibiofilm activity on other marine bacteria such as Flavobacterium species that are pathogenic for fish, and human pathogens in both the medical environment, such as Staphylococcus aureus and Pseudomonas aeruginosa, and in applications could be envisaged for the SNIV2006 compounds, both in aquaculture Targets for hydrogen-peroxide-induced damage to suspension and biofilm cells of Hydrogen peroxide (H2O2) is considered a major endogenous source of oxidative stress to oral bacteria and also is widely used in oral care products. Our study objectives were to identify specific targets for H2O2-induced damage to cells of Streptococcus mutans in suspensions and monospecies biofilms and to differentiate bacteriostatic and bactericidal actions of the peroxide. Streptococcus mutans was grown in suspension cultures and fed-batch biofilms for assessing relative sensitivities of viability, glycolysis, and protein synthesis to H2O2 damage. Biofilm cells were found to have essentially the same peroxide sensitivity as cells in suspensions. H2O2 at low concentrations of about 16 mmol/L was highly inhibitory for glycolysis and mainly bacteriostatic. The most sensitive target detected for glycolytic inhibition was glyceraldehyde-3-phosphate dehydrogenase with IC50 (50% inhibitory concentration) values of ca.
2 mmol/L for suspension cells and 2 mmol/L for biofilms with 15 min treatments. The phosphoenolpyruvate:glucose phosphotransferase pathway was less sensitive with an IC50 of ca. 10 mmol/L. Aldolase was not inhibited at bacteriostatic concentrations of the peroxide. For suspensions and biofilms, acidification somewhat diminished peroxide sensitivity, while increased temperature enhanced sensitivity. At concentrations above about 30 mmol/L, H2O2 became mainly bactericidal but not mutagenic for S. mutans.
A major target for bactericidal damage was protein synthesis, thus rendering cells incapable of repairing or replacing oxidatively damaged Antibiotic loaded β-tricalcium phosphate/calcium sulfate for antimicrobial potency, prevention and killing efficacy of Pseudomonas aeruginosa and Biofilm Innovation Centre (NBIC), Department of Mechanical Engineering, This study investigated the efficacy of a biphasic synthetic β-tricalcium phosphate/calcium sulfate (β-TCP/CS) bone graft substitute for compatibility with vancomycin (V) in combination with tobramycin (T) or gentamicin (G) evidenced by the duration of potency and the prevention and killing efficacies Antibiotic loaded β-TCP/CS beads were compared with antibiotic loaded beads formed from a well characterized synthetic calcium sulfate (CS) bone void filler. β-TCP/CS antibiotic loaded showed antimicrobial potency against PAO1 in a repeated Kirby-Bauer like zone of inhibition assay for 6 days compared to 8 days for CS. However, both bead types showed potency against SAP231 for 40 days. Both formulations loaded with V + T completely prevented biofilm formation (CFU below detection limits) for the 3 days of the experiment with daily fresh inoculum challenges (P < 001). In addition, both antibiotic loaded materials and antibiotic combinations significantly reduced the bioburden of pre-grown biofilms by between 3 and 5 logs (P < 001) with V + G performing slightly better against PAO1 than V + T. Our data, combined with previous data on osteogenesis suggest that antibiotic loaded β-TCP/CS may have potential to stimulate osteogenesis through acting as a scaffold as well as simultaneously protecting against biofilm infection. Future in vivo experiments and clinical investigations are warranted to more comprehensively evaluate the use of β-TCP/CS in the management of orthopaedic infections.
NJ and JRB have no competing interests. Influence of culture conditions on Escherichia coli O157:H7 biofilm formation by Biofilms are complex microbial communities that are resistant against attacks by bacteriophages and removal by drugs and chemicals.
