Antibacterial Properties of Stainless Steel Coated on Ti6Al4V Alloy

open access journalTitanium alloys and stainless steeltype 316Lare used in biomedical applications due to their high corrosion resistance and good biocompatibility properties. In this study, a functionally graded material composed of titanium and stainless steel was fabricated usinga powder metallurgical technique. Ti6Al4V alloy powder was placed as a substrate into a graphite crucible and stainless steel powder was added as a thin layer on the Ti6Al4V powder. The two layers were consolidated in-situ using a uniaxial hot press. The sintering process was carried out at 1050 oC for 30 minutes under 50 MPa. The pressure was maintained during the whole sintering process. A disc shape compact of 20 mmdiameter and 5 mmthickness was obtained aftersintering. The samples were metallographically prepared and their antibacterial properties were evaluated. A strong bonding was observed between the Ti6Al4V substrate and the 316L stainless steel layer, and no bacteria were observed on the stainless steel surface

Self-assembling dipeptide antibacterial nanostructures with membrane disrupting activity.

Peptide-based supramolecular assemblies are a promising class of nanomaterials with important biomedical applications, specifically in drug delivery and tissue regeneration. However, the intrinsic antibacterial capabilities of these assemblies have been largely overlooked. The recent identification of common characteristics shared by antibacterial and self-assembling peptides provides a paradigm shift towards development of antibacterial agents. Here we present the antibacterial activity of self-assembled diphenylalanine, which emerges as the minimal model for antibacterial supramolecular polymers. The diphenylalanine nano-assemblies completely inhibit bacterial growth, trigger upregulation of stress-response regulons, induce substantial disruption to bacterial morphology, and cause membrane permeation and depolarization. We demonstrate the specificity of these membrane interactions and the development of antibacterial materials by integration of the peptide assemblies into tissue scaffolds. This study provides important insights into the significance of the interplay between self-assembly and antimicrobial activity and establishes innovative design principles toward the development of antimicrobial agents and materials

Soya bean tempe extracts show antibacterial activity against Bacillus cereus cells and spores

Aims: Tempe, a Rhizopus ssp.-fermented soya bean food product, was investigated for bacteriostatic and/or bactericidal effects against cells and spores of the food-borne pathogen Bacillus cereus. Methods and results: Tempe extract showed a high antibacterial activity against B. cereus ATCC 14579 based on optical density and viable count measurements. This growth inhibition was manifested by a 4 log CFU ml-1 reduction, within the first 15 min of exposure. Tempe extracts also rapidly inactivated B. cereus spores upon germination. Viability and membrane permeability assessments using fluorescence probes showed rapid inactivation and permeabilization of the cytoplasmic membrane confirming the bactericidal mode of action. Cooked beans and Rhizopus grown on different media did not show antibacterial activity, indicating the unique association of the antibacterial activity with tempe. Subsequent characterization of the antibacterial activity revealed that heat treatment and protease addition nullified the bactericidal effect, indicating the proteinaceous nature of the bioactive compound. Conclusions: During fermentation of soya beans with Rhizopus, compounds are released with extensive antibacterial activity against B. cereus cells and spores. Significance and Impact of Study: The results show the potential of producing natural antibacterial compounds that could be used as ingredients in food preservation and pathogen contro

Importance of understanding variable and transient energy demand in large multi-product industrial plants for process integration

There have been some news releases claiming that Professor Henle in Germany has found the chemical identity of UMF, and that in future chemical analysis will be used instead of assays of antibacterial activity to indicate the level of UMF in manuka honey. Both of these claims are misleading. Because the level of active substance in manuka honey is an unreliable indication of the level of antibacterial activity and can be very misleading, it is hard to see any commercial advantage for it to be used to indicate antibacterial activity other than if someone wanted to fool the consumer into thinking that the higher numbers are giving them a level of antibacterial activity that is far higher than they are really getting

The potential of Symbiont Ba cteria in Melo melo Gastropod found in Pekalongan Waters as a source of MDR antibacterial active compound

The increasing resistance of many pathogenic microorganisms against antibiotics compounds creates an alarming issue in medical world. This concern has created research opportunities in new antibiotics compounds as alternative options. The gastropod Melo melo is a species whose main diet consists of other smaller gastropods. However, Melo-melo does not have any self-defense mechanism save for its thin shell. To protect itself from various pathogenic bacteria existing in its food, Melo melo produces secondary metabolites, which are suspected to contain bioactive compounds with antibacterial properties. This fact puts Melo melo as a marine biota with potential as a source of new antibacterial compounds. This research aims to discover the potency of symbiont bacteria in the gastropod Melo melo with capabilities in producing Multi-drug resistant (MDR) antibacterial compounds. Samples of Melo melo are collected from the vicinity of Pekalongan waters, Central Java, Indonesia. This research begins with the isolation of symbiont bacteria, screening of symbiont bacteria with potency in MDR antibacterial activities, antibacterial test, and isolation of MDR clinical pathogenic bacteria. These protocols are then followed by antibacterial sensitivity test, and identification of bacterial species active against MDR by biochemical test and molecular analysis. Molecular analyses are carried out sequentially by DNA extraction, DNA amplification by PCR, and DNA sequencing. Results of 16S rDNA are analyzed using Genetix program and then followed by sequence analysis of the 16S rDNA. In this research, 11 bacteria in Melo melo are isolated and there are 4 isolates which show antibacterial activities against MDR bacteria from Pseudomonas sp. and Enterobacter sp species. Molecular analysis of the most active isolates identifies that isolate PM 26 matches in characteristics with Brevibacterium celere strain KMM 3637 with 89% homology match. On the other hand, biochemical test shows that isolate PM 26 is identical with Bacillus sp. This research concludes that symbiont bacteria found in Melo melo possess antibacterial activities against bacteria of MDR strain

Honey: Antimicrobial actions and role in disease management

The ancient treatment of dressing infected wounds with honey is rapidly becoming re-established in professional medicine, especially where wounds are infected with antibiotic-resistant bacteria. This is because of the demonstrated sensitivity of such bacteria to the antibacterial activity of honey, which is not influenced by whether or not strains are resistant to antibiotics. Honey has been found to have a very broad spectrum of activity, but its potency of antibacterial activity can vary greatly. In most honeys the antibacterial activity is due to enzymatically produced hydrogen peroxide and thus the potency of its antibacterial activity can be decreased by catalase present in an open wound. Manuka honey has an antibacterial component derived from the plant source. Manuka honey with a quality-assured level of antibacterial activity is being used by companies marketing honey products for wound care that are registered with the medical regulatory authorities in various countries. Such honey can be diluted IO-fold or more and still completely inhibit the usual wound-infecting species. There is a large amount of clinical evidence for the effectiveness of honey in clearing infection in wounds, and some clinical evidence of its effectiveness in treating other infections. Although the antibacterial potency of honey is insufficient to allow its use systemically, there are various clinical applications besides wound care in which it is used topically or where it does not get excessively diluted, such as for treatment of gastritis, enteritis, gingivitis, ophthalmological infections and bronchial infections. In most of these applications the anti-inflammatory activity of honey is of additional benefit in decreasing the inflammation resulting from infection. Additional clinical research is needed to provide better evidence of the effectiveness of honey in these therapeutic applications of honey

The Antibacterial Activity of Leaf Extracts of Eucalyptus camaldulensis (Myrtaceae)

The antibacterial activity of the leaf extracts of Eucalyptus camaldulensis was studied against Klebsiella spp, Salmonella typhi, Yersinia enterocolitica, Pseudomonas aeruginosa (Gram-negative), Staphylococcus aureus and Bacillus subtilis by the agar diffusion method. The methanol extract, dichloromethane fraction and methanol residue at 10mg mL-1 displayed broad spectrum activity against all the test organisms but the petroleum ether fraction showed no activity. The antibacterial activity of the extracts was compared to the drug gentamycin. The minimum inhibitory concentrations of the methanol extract and dichloromethane fraction determined by the agar dilution method ranged between 0.04 and 10mg mL-1 with that of Bacillus subtilis being the least. Phytochemical screening of the plant revealed the presence of tannins, saponins and cardiac glycosides. The results of this study support the traditional use of Eucalyptus camaldulensis leaves as an antibacterial agent. Key words: Eucalyptus camaldulensis, antibacterial activity, minimum inhibitory concentration, methanol extract, dichloromethane fractio

Facilitators and barriers to the successful implementation of pediatric antibacterial drug trials: Findings from CTTI's survey of investigators.

An urgent need exists to develop new antibacterial drugs for children. We conducted research with investigators of pediatric antibacterial drug trials to identify facilitators and barriers in the conduct of these trials. Seventy-three investigators completed an online survey assessing the importance of 15 facilitators (grouped in 5 topical categories) and the severity of 36 barriers (grouped in 6 topical categories) to implementing pediatric antibacterial drug trials. Analysis focused on the identification of key factors that facilitate the successful implementation of pediatric antibacterial drug trials and the key barriers to implementation. Almost all investigators identified two factors as very important facilitators: having site personnel for enrollment and having adequate funding. Other top factors were related to staffing. Among the barriers, factors related to parent concerns and consent were prominent, particularly obtaining parental consent when there was disagreement between parents, concerns about the number of blood draws, and concerns about the number of invasive procedures. Having overly narrow eligibility criteria was also identified as a major barrier. The survey findings suggest three areas in which to focus efforts to help facilitate ongoing drug development: (1) improving engagement with parents of children who may be eligible to enroll in a pediatric antibacterial drug trial, (2) broadening inclusion criteria to allow more participants to enroll, and (3) ensuring adequate staffing and establishing sustainable financial strategies, such as funding pediatric trial networks. The pediatric antibacterial drug trials enterprise is likely to benefit from focused efforts by all stakeholders to remove barriers and enhance facilitation