Sutures are considered as surgical materials that form excellent surfaces to integrate the postoperative parts of the body. These materials present suitable platforms for potential bacterial penetrations. Therefore, coating these biomedical materials with biocompatible compounds is seen as a potential approach to improve their properties while avoiding adverse effects. The aim of this study was to evaluate Arthrospira platensis, Haematacoccus pluvialis, Chlorella minutissima, Botyrococcus braunii, and Nostoc muscorum as potential surgical suture coating materials. Their crude extracts were absorbed into two different sutures as poly glycolic (90%)-co-lactic acid (10%) (PGLA) and poly dioxanone (PDO); then, their cytotoxic effects and antibacterial activities were examined. Both N. muscorum-coated sutures (PGLA and PDO) and A. platensis-coated (PGLA and PDO) sutures did not induce any toxic effect on L929 mouse fibroblast cells (>70% cell viability). The highest antibacterial activity against Staphylococcus aureus was achieved with N. muscorum-coated PGLA and A. platensis-coated PGLA at 11.18 ± 0.54 mm and 9.52 ± 1.15 mm, respectively. These sutures were examined by mechanical analysis, and found suitable according to ISO 10993-5. In comparison with the commercial antibacterial agent (chlorohexidine), the results proved that N. muscorum extract can be considered as the most promising suture coating material for the human applications.

The aim of this study was to evaluate the antibacterial activity, quality and stability of creams (at 1 % concentration) prepared with synthesized silver(I) complexes: [Ag(Nam)2]NO3·H2O ( AgNam), [Ag2(HGly)2]n(NO3)2n (AgGly) (Nam - nicotin-amide, Gly - glycine) and silver(I) sulfadiazine (AgSD), which is commercially available. Antibacterial activity was evaluated by agar well diffusion method and in in vivo case. The pure silver(I) complexes as well as all three tested creams loaded with AgGly, AgSD and AgNam showed antibacterial potential. Moreover, the creams loaded with AgGly and AgNam showed higher antibacterial effects against S. aureus and B. subtilis than the cream loaded with AgSD. In terms of appearance, all cream samples were opaque and odourless, and no phase separation was observed. Creams were soluble in water (o/w emulsions) and they had a pseudoplastic behaviour. The pH of the creams was in the range of 4.87-5.75. No visible changes were observed in the case of commercially used AgSD cream during one month testing period at conditions -16 ± 1 °C; 6 ± 1 °C and 56 % relative humidity; 20 ± 1 °C and 58 % relative humidity and 40 ± 1 °C and 75 % relative humidity. However, creams containing AgGly and AgNam changed their colour depending on the tested conditions.

Mineral compounds, as pigments and therapeutics, appeared regularly in the technical and medical texts of the Greco-Roman (G-R) world. We have referred to them as \'G-R medicinal minerals\' and we suggest that despite their seeming familiarity, there are actually many unknowns regarding their precise nature and/or purported pharmacological attributes. Earth pigments are part of that group. This paper presents a brief overview of our work over the past twenty years relating to: a. the attempt to locate a select number of them in the places of their origin; b. their chemical/mineralogical characterization; c. the study of their ecology via the identification of the microorganisms surrounding them; d. their testing as antibacterials against known pathogens. In the process, and to fulfil the above, we have developed a novel methodological approach which includes a range of analytical techniques used across many disciplines (mineralogy, geochemistry, DNA extraction and microbiology). This paper focuses on a select number of earth pigments deriving from the island of Melos in the SW Aegean, celebrated in antiquity for its Melian Earth, a white pigment, and asks whether they might display antibacterial activity. We demonstrate that some (but not all) yellow, green and black earth pigments do. We also show that the manner in which they were dispensed (as powders or leachates) was equally important. The results, although preliminary, are informative. Given their use since deep time, earth pigments have never lost their relevance. We suggest that the study of their ecology/mineralogy and potential bioactivity allows for a better understanding of how our perception of them, as both pigments and therapeutics, may have evolved.

Some studies focused on metabolic relationships between plants and their endophytic bacterial associates, and more research is required to generate critical evidence for these relationships. In the current interest, we tried to confirm the relationship between the traditional medicinal plant, Calotropis procera (Aiton) W.T. Aiton, and its associated endophytes, Bacillus siamensis and Bacillus amyloliquefaciens, as the first matching study regarding the production of bioactive secondary metabolites from the plant vis-a-vis its bacterial endophytes.Secondary metabolites of both the plant and its endophytic bacteria were extracted using different solvents, e.g., water, methanol, and ethyl acetate. All extracts exhibited high quantities of phenolics, flavonoids, tannins, and saponins. In addition, they showed significant antioxidant capacity which was found to be positively correlated with total phenolic contents. The highest total antioxidant capacity (99.28 ± 0.0 mg AA equivalent/g extract) was measured for the aqueous extract of B. siamensis.Antibacterial activity of the different extracts was evaluated against certain pathogenic bacteria, i.e., Escherichia coli, Klebsiella pneumoniae, Streptococcus agalactiae, Salmonella typhi, Serratia marcescens, and Staphylococcus aureus. It was strikingly found that the broadest antibacterial spectrum was revealed by extracts of both C. procera and its endophytic B. siamensis. Interestingly, antibacterial activity was significantly correlated to phenolic and flavonoid contents.

Lanthipeptides are intriguing peptides known since 1928, the year of penicillin\'s discovery. At that time, they were known as lantibiotics due to their (methyl)lanthionine amino acids and antibacterial activity. Their body of knowledge expanded tremendously over the last few years. Our analysis reveals that Bacteroidetes has a high state of clusters encoding the biosynthesis of class I lanthipeptides. We show that some strains of Pedobacter have a number of LanBs/genome comparable to that of some Actinobacteria. The case study selected was Pedobacter lusitanus NL19. Its clusters identified encode LanBs associated with LanCs as well as orphan LanBs. The first are concomitant with LanT transporters typical of class II lanthipeptides (and not class I), making their clusters into a hybrid class I and class II type. So far, this kind of operon was described only once and is involved in the production of pinensins, the first lanthipeptide with antifungal activity. A particular feature of pinensins is their splitted LanBs and we found that these enzymes are also widely encoded in Bacteroides. The function of a high percentage of proteins predicted to play a role in the production of Pedobacter lanthipeptides is unknown. Other major fraction of these proteins is expected to be enrolled in signal-transduction pathways. We demonstrate that the occurrence of lanthipeptides clusters in the genomes of Gram-negative bacteria is higher than previously reported. More importantly, we show that their genetic background is highly diverse, which is an undeniable foreshadowing of novel peptide structures, biochemistry and biological function.

A total of 332 staphylococcal strains, mainly isolated from meat, were screened for antibacterial activity. Eighteen strains exhibited antibacterial activity towards species within the same genus. These antibacterial strains were further screened against Clostridium botulinum, to assess their potential as anticlostridial starter cultures for the development of fermented meat products without added nitrate or nitrite. Only Staphylococcus sciuri IMDO-S72 had the ability to inhibit all clostridial strains tested, whilst displaying additional activity against Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. Apart from their potential as bioprotective cultures, the staphylococcal collection was also screened for biogenic amine production, as these compounds may compromise food quality. To this end, ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was applied. A low incidence of biogenic amine production was found, with tyramine and β-phenylethylamine being the most prevalent ones. Concentrations remained relatively low (< 52 mg/L) after a prolonged incubation period, posing no or little threat towards food safety. Taken together, S. sciuri IMDO-S72 could serve as an interesting candidate for the bioprotection of fermented meats as it showed promising antibacterial activity as well as absence of biogenic amine production.

OBJECTIVE: Eight extremophile plants from Tunisia were screened to find natural products with benefits in human health.
METHODS: These plants were collected in different areas in Tunisia. Their methanolic extracts were evaluated for their total phenolic content and for their antiradical (DPPH), antimicrobial (on 35 bacteria and one yeast), antiviral (hepatitis C virus, HCV) and cytotoxic activity (against WI38 and J774 cell lines). The most active species were subjected to a bioguided fractionation.
RESULTS: The screening revealed promising activity for four plants, but two species have both antiradical and antimicrobial activity: Juncus maritimus and Limonium virgatum. The rhizomes extract of J. maritimus showed the highest activity against HCV, a selective antibacterial activity against Streptococcus dysgalactiae, and a moderate antiradical activity which is due to luteolin isolated in one step by centrifugal partition chromatography. The stems\' and leaves\' extracts of L. virgatum were rich in polyphenols responsible for the antiradical activity. Also, Limonium extracts showed an antibacterial activity with a broad spectrum.
CONCLUSIONS: Extremophile plants have proven to be a promising source for bioactive metabolites. They have a powerful antioxidant system highly influenced by biotic and abiotic factors and the ability to produce secondary metabolites with antimicrobial activity.

Nicotinamide, the amide form of vitamin B3, was demonstrated to combat some of the antibiotic-resistant infections that are increasingly common around the world. The objective of this study was to thoroughly understand the formulation and process variabilities affecting the preparation of nicotinamide-loaded polymeric nanoemulsified particles. The quality target product profile and critical quality attributes of the proposed product were presented. Plackett-Burman screening design was employed to screen eight variables for their influences on the formulation\'s critical characteristics. The formulations were prepared by an oil-in-water emulsification followed by solvent replacement. The prepared systems were characterized by entrapment capacity (EC), entrapment efficiency (EE), particle size, polydispersity index, zeta potential, transmission electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, in vitro drug release, and their antibacterial activity against bacterial scrums. EC, EE, particle size, polydispersity index, zeta potential, and percentage release in 24 hours were found to be in the range of 33.5%-68.8%, 53.1%-67.1%, 43.3-243.3 nm, 0.08-0.28, 9.5-53.3 mV, and 5.8%-22.4%, respectively. One-way analysis of variance and Pareto charts revealed that the experimental loadings of 2-hydroxypropyl-β-cyclodextrin and Eudragit(®) S100 were the most significant for their effects on nicotinamide EC and EE. Moreover, the polymeric nanoemulsified particles demonstrated a sustained release profile for nicotinamide. The Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction demonstrated a significant interaction between the drug and 2-hydroxypropyl-β-cyclodextrin that might modulate the sustained release behavior. Furthermore, the formulations provided a sustained antibacterial activity that depended on nicotinamide-loading concentration, release rate, and incubation time. In conclusion, the study demonstrated the potential of polymeric nanoemulsified system to sustain the release and antibacterial activity of nicotinamide.

In the marine environment organochlorine insecticides can be broadly detected in water, sediments, and biota. These pollutants may have major ecological consequences since they may affect marine organisms and endanger organismal growth, reproduction or survival. In this study we investigated the modification of some sea urchin immunological parameters in response to subchronic lindane (γ-HCH) exposure. Adult specimens of the sea urchin Paracentrotus lividus were exposed to two different concentrations (0.1 and 0.5 mg L(-1)) of lindane. After 24 and 48h of treatment, we examined the lindane influence on coelomocytes vitality and enumeration as well on some humoral parameters. Our results showed that the presence of the pesticide affected both cellular and humoral components of the immune system. In particular, P. lividus coelomocytes vitality did not change but a decrease of the total cell number and an increase of the red cells was recorded. Haemolytic and lysozyme-like activities as well as antibacterial activity on Vibrio alginolyticus of treated animals decreased. Sea urchin immunological competence modifications might represent a tool for monitoring disease susceptibility thus providing biological criteria for the implementation of water quality standards to protect marine organisms.

Silver has long been advocated as an effective antimicrobial. However, toxicity issues with silver have led to limited use of silver in nanoform, especially for food preservation. With the aim of exploring combinatorial options that could increase the antibacterial potency of silver nanoparticles and reduce the effective dosage of silver, we evaluated the extent of synergy that a combination of silver nanoparticles and an essential oil representative (cinnamaldehyde) could offer. A battery of gram-positive and gram-negative bacterial strains was utilized for antibacterial assays, and extents of synergism were calculated from fractional inhibitory concentration indices. The activity of nanoparticles was greatly enhanced when utilized in the presence of cinnamaldehyde. We observed combinatorial effects that were strongly additive against all the bacterial strains tested, and genuine synergy was found against spore forming Bacillus cereus and Clostridium perfringens - bacterial strains associated with release of cytotoxins in contaminated food and known for their persistence. Bacterial kill curve analysis revealed a very fast bactericidal action when a combination of two agents was used. The electron and atomic force microscopy also revealed extensive damage to the bacterial cell envelop in the presence of both agents. We also performed hemolysis assays to investigate and approximate the extent of toxicity exhibited by the two agents, and observed no adverse effect at the concentrations required for synergy. This study shows that safe levels of silver in nanoform in combination with essential oil component cinnamaldehyde can be effectively used for controlling the spore-forming bacterial species.