Wide Spectrum Of Antimicrobial Activity Research Articles

Combined effect of brazilin-rich extract and lawsone methyl ether against infection-causing bacteria

Bacterial contamination and infection widely affect the food, pharmaceutical and biomedical industries. Additionally, these bacteria developed resistance to synthetic antibiotics causing public health danger, globally. Natural plant extracts (NPE) are suitable alternatives to synthetic antibiotics to tackle antimicrobial resistance problems. Furthermore, a blend or combination of different NPEs exerts a wide spectrum of antimicrobial activity. Therefore, the combined effect of brazilin-rich extract (BRE) and lawsome methyl ether (LME) against infection-causing common bacteria were evaluated. BRE had a lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against most of the Gram-negative bacteria (Salmonella typhi, Salmonella typhimurium and Pseudomonas aeruginosa) while LME was active against most of the Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus epidermidis). The combination of BRE and LME at 2:1 and 1:1 concentration significantly reduced the MIC value of each compound as compared to either BRE or LME concentration alone (P < 0.05). Further time-kill kinetics revealed a 3.0–3.5 log reduction in Gram-positive bacteria and a 2.5–3.0 log reduction in Gram-negative bacteria during 120 min of incubation, respectively. Therefore, a combination of BRE and LME was recommended as natural antibacterial to synthetic antibiotics for food and pharmaceutical applications.

Antibacterial Evaluation of Gallic Acid and its Derivatives against a Panel of Multi-drug Resistant Bacteria.

Infectious diseases are the second leading cause of deaths worldwide. Pathogenic bacteria have been developing tremendous resistance against antibiotics which has placed an additional burden on healthcare systems. Gallic acid belongs to a naturally occurring phenolic class of compounds and is known to possess a wide spectrum of antimicrobial activities. In this study, we synthesized thirteen derivatives of gallic acid and evaluated their antibacterial potential against seven multi-drug resistant bacteria, as well as cytotoxic effects against human embryonic kidney cell line in vitro. Methods: 13 compounds were successfully synthesized with moderate to good yield and evaluated. Synthesized derivatives were characterized by using nuclear magnetic resonance spectroscopy, mass spectrometry, and Fourier transformation infrared spectroscopy. Antibacterial activity was determined using microdilution while cytotoxicyt was assessed using MTT assay. The results of antibacterial assay showed that seven out of thirteen compounds exhibited antibacterial effects with compound 6 and 13 being most potent against Staphylococcus aureus (MIC 56 μg/mL) and Salmonella enterica (MIC 475 μg/mL) respectively. On the other hand, most of these compounds showed lower cytotoxicity against human embryonic kidney cells (HEK 293), with IC50 values ranging from over 700 μg/mL. Notably, compound 13 was found to be non-toxic at concentrations as high as 5000 μg/mL. These findings suggest that the present synthetic derivatives of gallic acid hold potential for further studies in the development of potent antibacterial agents.

Phenolic compounds and antimicrobial activity of leaves of the genus Sorbus species and natural hybrids

The identification of new sources of biologically active substances is an actual direction of research in recent years, in particular, the demand for antimicrobial compounds and natural preservatives of plant origin is growing. Plants of the genus Sorbus L. are known in folk medicine, but for the rational use of plant material, there is a lack of systematic study of the features of the secondary metabolites’ accumulation and the spectrum of biological activity of plants during vegetation in different environmental conditions. In the present work, the seasonal dynamics of the total content of polyphenols, flavonoids and free phenolic acids in the leaves of rowan plants natural to the flora of Ukraine and introduced in the steppe region were investigated. The highest accumulation of phenolic compounds was found in the leaves of S. domestica, S. latifolia, S. hybrida, S. torminalis and S. aucuparia in the first half of June, and in S. aria and S. intermedia in May, which will serve as a criterion for selecting the best plant material to obtain biologically active compounds. The seasonal dynamics of the content of flavonoids and phenolic acids in the leaves of plants had significant species differences, which require more in-depth studies of the phytocompounds component composition. Antimicrobial activity of leaf ethanol extracts of rowan plant was found to be high against gram-negative bacterial strain Klebsiella pneumoniae B920 (especially the activity of S. aria, S. intermedia and S. aucuparia extracts) and Pseudomonas aeruginosa B907 (especially the activity S. torminalis and S. domestica), clinical gram-positive strains of Staphylococcus epidermidis (the highest activity of S. aria, S. domestica and S. intermedia extracts), as well as against clinical strains of fluconazole-resistant fungus Candida albicans (especially the activity of extracts of S. latifolia S. torminalis and S. intermedia). A conclusion was made about the prospects of using leaf extracts of the genus Sorbus plants as an economical and affordable natural source of biologically active polyphenols with a wide spectrum of antimicrobial activity. Further research may be aimed at elucidating the component composition of rowan leaf extracts and establishing the relationship between individual phytocompounds and the antimicrobial effects of plant extracts.

Heterologously expressed SacP23, a novel bacteriocin from Paenibacillus polymyxa #23, is active against methicillin resistant Staphylococcus aureus.

Antimicrobial peptides have the potential to be used in a range of applications, including as an alternative to conventional antibiotics for the treatment of bacterial infections of humans and animals. Therefore, there is interest in identifying novel bacteriocins which have desirable physico-chemical properties or antimicrobial activities. Paenibacillus polymyxa #23, isolated from a marine sponge, has wide spectrum antimicrobial activity against Gram-negative and Gram-positive bacteria. To explore the basis of this antimicrobial activity, the complete genome sequence of the strain was examined. Multiple genes predicted to encode antimicrobial peptides were identified. One gene was predicted to encode a novel sactipeptide bacteriocin, named SacP23. To confirm that SacP23 does have antimicrobial activity and to explore the antimicrobial spectrum of the peptide it was heterologously expressed in Bacillus subtilis. A cluster of eight genes, encoding a full complement of accessory genes as well as the structural gene expressed from the native promoter, was cloned into B. subtilis BS54A. The recombinant strain displayed antimicrobial activity against several Gram-positive bacteria, including multi-drug resistant Staphylococcus aureus. Heterologous expression of a whole gene cluster offers a powerful way to interrogate and resolve the various antimicrobial activities expressed by native strains that encode multiple compounds of interest.

The effects of topical mafenide acetate application on skin graft survival in bacterial contaminated wounds

BackgroundInfection related skin graft loss still remains as a common problem even with the use of systemic antibiotics. Mafenide acetate (Sulfamylon) is a topical antimicrobial agent with a wide spectrum of antimicrobial activity. Since mafenide acetate has the ability to penetrate the burn eschar, it was preferred in the treatment of infected full-thickness skin grafts. We investigated the effects of topical Mafenide acetate application on graft survival in an experimental model of contaminated wound beds in rats. Materials and methodsTwenty-eight male Wistar albino rats were included in the study. A full-thickness skin graft (FTSG) was harvested from the back region and the wound bed was inoculated with Pseudomonas aeruginosa. The same FTSG was sutured in place. Rats were divided into 4 groups. In groups 1 and 2, wound care was performed with gauze and hydrofiber dressings respectively. In groups 3 and 4, Mafenide acetate soaked hydrofiber and Mafenide acetate soaked gauze dressings were used respectively. The dressings were closed for 4 days in all groups. The rats in groups 1 and 2 received dressing changes every day. The dressing of the rats in group 3 was changed once every two days. The dressing of the rats in group 4 was changed twice a day. ResultsIn groups 3 and 4, the graft survival rates decreased significantly from day 7 to day 14 in all groups. Histologically, detachment at the dermoepidermal junction, disorganization of collagen along with increased numbers of fibroblasts and a decrease in graft adhesion to the wound bed were determined in Mafenide acetate-treated groups. ConclusionIn rats treated with Mafenide acetate, graft survival was higher on day 7 and gradually decreased towards day 14. Application of a 2.5% solution of Mafenide acetate longer than 7 days on inoculated skin grafts in a rat model causes significant cytotoxicity and graft loss.

Characterization of bacteriocin produced by Brevibacillus laterosporus Tk3 isolated from ‘tatwakhar’ – a flour prepared from seeds of Aesculus indica in remote areas of Himachal Pradesh India

Bacteriocin producing strain Brevibacillus laterosporus TK3, was isolated from ‘Tatwakhar’- a flour prepared from seeds of Indian Horse Chestnut (Aesculus indica). Bacterial strain Brevibacillus laterosporus TK3 identified by morphological, biochemical techniques followed by 16S rRNA gene sequencing. The 16S rRNA sequence of bacteriocin producer was deposited in NCBI GenBank under accession no. KP861913.1. Bacteriocin of Brevibacillus laterosporus TK3 showed strong antagonistic activity against food spoiling/pathogenic bacteria viz. Listeria monocytogenes, Staphylococcus aureus and Clostridium perfringens. Bacteriocin production by Brevibacillus laterosporus TK3 was enhanced by optimizing production time, pH of the medium, inoculum size and incubation temperature. Maximum bacteriocin activity (6000 AU/ml) was recorded/obtained in basal salt medium of pH 5.5 with an inoculum size of 1.5 OD at 10% and incubation period of 24h at 35 °C. The bacteriocin was purified by single step gel exclusion chromatography. Molecular weight of active bacteriocin from Brevibacillus laterosporous TK3 was found to be 6 kDa according to SDS PAGE. The molecular mass of purified bacteriocin was confirmed as 5953.89 Da by MALDI TOF analysis. The purified bacteriocin was found desirable/suitable for food preservation as it showed wide spectrum of antimicrobial activity, resistance to high temperature, wide pH range and sensitivity to proteolytic enzymes thus, making it safe for human consumption.

Iodinene Nanosheet-to-Iodine Molecule Allotropic Transformation for Antibiosis.

Iodine, as a typical haloid element in group VIIA, has been extensively applied as antiseptics clinically, thanks to its effective and wide-spectrum antimicrobial activity against bacteria, fungi, and viruses. Nevertheless, current iodic sterilizing agents are still limited to topical applications such as instrument sterilization and treatments of skin or mucous membrane infection due to its unsatisfactory stability and biocompatibility. Here, we propose an emerging two-dimensional iodine nanomaterial (noted as iodinene) for the treatment of infection diseases in vivo. Iodinene nanosheets were fabricated by a facile and environmentally friendly approach via sonication-assisted liquid exfoliation, which present an intriguing layered structure and negligible toxicity. The as-synthesized iodinene would experience an in situ allotropic transformation spontaneously to release active HIO and I2 molecules by reacting with H2O2 in the infectious microenvironment. By the in situ production of active HIO and I2 molecules via allotropic transformation, iodinene presents enhanced antibacterial efficacy against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. In vivo outcome demonstrates the desirable antibacterial efficacy of iodinene in treating bacterial wound infection and pneumonia. This study thus offers an alternative to conventional sterilizing agents against hard-to-treat bacterial infections.

Dosage Derivation of Marbofloxacin in Broiler Chickens based on Pharmacokinetic-Pharmacodynamic Integration

Marbofloxacin, a veterinary–exclusive antimicrobial drug of third–generation fluoroquinolone class, exhibits wide spectrum antimicrobial activity against Gram-negative as well as Gram-positive bacteria, and thus, is a promising agent to treat susceptible bacterial infections in poultry. Therefore, the present study was conducted to derive dosage regimen of marbofloxacin based on the results of intravenous and oral pharmacokinetic (PK) trial in sixteen healthy broiler chickens. Plasma concentrations of marbofloxacin were measured by optimized and in-house validated Ultra High Performance Liquid Chromatography (UHPLC) method. The PK parameters were calculated from plasma concentrations versus time data by non-compartmental analysis using ‘PK Solver 2.0’ software. Following oral administration of marbofloxacin at the dose rate of 5 mg/kg body weight, the mean maximal plasma concentration (Cmax: 2.193 µg/ml) was achieved at 1.68 h. Marbofloxacin showed long half-life (6.03 h), high volume of distribution (2.64 L/Kg) and good oral bioavailability (88.10 %). The average plasma concentration of marbofloxacin ≥ 0.32 µg/ml was maintained upto 12 h and 0.10 µg/ml at 24 h. Based on the values of PK-PD integrated indices, it is concluded that oral dose of marbofloxacin @ 5.0 mg/kg body weight, to be repeated at 24 h, would be efficient to treat common bacterial pathogens of broiler chickens having MIC ≤ 0.12 μg/ml.

Silver Nanoparticles and Their Therapeutic Applications in Endodontics: A Narrative Review

The efficient elimination of microorganisms and their byproducts from infected root canals is compromised by the limitations in conventional root canal disinfection strategies and antimicrobials. Silver nanoparticles (AgNPs) are advantageous for root canal disinfection, mainly due to their wide-spectrum anti-microbial activity. Compared to other commonly used nanoparticulate antibacterials, AgNPs have acceptable antibacterial properties and relatively low cytotoxicity. Owing to their nano-scale, AgNPs penetrate deeper into the complexities of the root canal systems and dentinal tubules, as well as enhancing the antibacterial properties of endodontic irrigants and sealers. AgNPs gradually increase the dentin hardness in endodontically treated teeth and promote antibacterial properties when used as a carrier for intracanal medication. The unique properties of AgNPs make them an ideal additive for different endodontic biomaterials. However, the possible side effects of AgNPs, such as cytotoxicity and tooth discoloration potential, merits further research.

The Effects of Propolis on Viral Respiratory Diseases.

Propolis remains an interesting source of natural chemical compounds that show, among others, antibacterial, antifungal, antiviral, antioxidative and anti-inflammatory activities. Due to the growing incidence of respiratory tract infections caused by various pathogenic viruses, complementary methods of prevention and therapy supporting pharmacotherapy are constantly being sought out. The properties of propolis may be important in the prevention and treatment of respiratory tract diseases caused by viruses such as severe acute respiratory syndrome coronavirus 2, influenza viruses, the parainfluenza virus and rhinoviruses. One of the main challenges in recent years has been severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing COVID-19. Recently, an increasing number of studies are focusing on the activity of various propolis preparations against SARS-CoV-2 as an adjuvant treatment for this infection. Propolis has shown a few key mechanisms of anti-SARS-CoV-2 action such as: the inhibition of the interaction of the S1 spike protein and ACE-2 protein; decreasing the replication of viruses by diminishing the synthesis of RNA transcripts in cells; decreasing the particles of coronaviruses. The anti-viral effect is observed not only with extracts but also with the single biologically active compounds found in propolis (e.g., apigenin, caffeic acid, chrysin, kaempferol, quercetin). Moreover, propolis is effective in the treatment of hyperglycemia, which increases the risk of SARS-CoV-2 infections. The aim of the literature review was to summarize recent studies from the PubMed database evaluating the antiviral activity of propolis extracts in terms of prevention and the therapy of respiratory tract diseases (in vitro, in vivo, clinical trials). Based upon this review, it was found that in recent years studies have focused mainly on the assessment of the effectiveness of propolis and its chemical components against COVID-19. Propolis exerts wide-spectrum antimicrobial activities; thus, propolis extracts can be an effective option in the prevention and treatment of co-infections associated with diseases of the respiratory tract.

Chemotypes of Species of the Genus Thymus L. in Carpathians Region of Ukraine—Their Essential Oil Qualitative and Quantitative Characteristics and Antimicrobial Activity

The study of the R&amp;D in this paper is to determine the range of essential oils (EOs) in the raw materials of species of the genus Thymus of the natural flora in the Carpathian region and their antimicrobial activity. It was found that the component range of EO in species of the genus Thymus depends on the microclimatic conditions of the population. The range of essential oils in the raw material of Th. Serpyllum and Th. Pulegoides is 7–9 mL and Th. Marschallianus is 3.5 mL. The research found that the plants Th. Serpyllum and Th. Pulegoides that grow in sunny habitats have an aromatic mono- and bicyclic monoterpenoid chemotype (K/α-T-neol/ G/p-C/B), with total dominance of carvacrol and p-cymene. The populations of Th. Serpyllum, which grow on the edges of sparse pine forests, and populations of Th. Pullegioide, with denser plant cover and which grow in meadows, have an acyclic and bicyclic monoterpene chemotype (G/α-T-neol/B/K). Plants that grow in the communities of meadow-steppe vegetation have the following chemotypes: Th. Serpyllum—L/K/G with 63% of linalool, Th. Pullegioides—G/α-T-neol/L/B, and Th. Marschallianus—α-T-neol/K/L/α-T-nen/G/B. Of these, the dominant chemotypes are α-terpineol and carvacrol (28:6.5%). A wide spectrum of antimicrobial activity was registered in samples of Th. Pullegoides and Th. Serpyllum that have an aromatic-monoterpenoid chemotype. Essential oils of Th. Pullegoides were dominated by carvacrol, and p-cymene had the highest fungicidal action (41.00 ± 1.0%). Plant populations of Th. Pullegoides and Th. Serpyllum with the aromatic-monoterpenoid chemotype are suggested by R&amp;D to be of use in the pharmaceutical industry. They have high contents of natural components, which are effective in a wide spectrum of antimicrobial activity. The EO of Th. Marschallianus had the lowest influence on the inhibition of bacterial and fungal reproduction.

Prevention of gastrointestinal diseases in piglets at weaning using probiotics Bacillus coagylans and Bacillus megaterium

The aim of the study is to determine the preventive effect of the use of probiotics Bacillus coagulans and Bacillus megaterium in case of gastrointestinal diseases in piglets and as a potential strategy to reduce the misuse of antibiotics in monogastric animals by adding probiotics to the diet of pregnant sows and piglets in the period before and after weaning.&#x0D; Materials and methods. Three research groups were formed to study the preventive effect of probiotics of the genus Bacillus coagulans and Bacillus megaterium. The piglets of the first experimental group received probiotics at the rate of 0.4 kg per 1 ton of feed in the periods before and after weaning, and that is, the moment of the entire study, the second experimental group received probiotics in the period after weaning, before that they received milk from the sow. The third group was the control group, which received only milk from the sow, and fodder during the weaning period. The effectiveness of the prevention result was determined by the absence/presence of clinical signs of morbidity and % survival of animals during the study period.&#x0D; The results. It was established that the preservation of livestock in the 1st experimental group was 90 %, and in the 2nd group – 70 %, and control – 50 %.&#x0D; Conclusions. Research results show that probiotics of the genus Bacillus coagulans and Bacillus megaterium, the components of which provide a wide spectrum of antimicrobial activity, are a reliable preventive measure for gastrointestinal diseases in piglets.

Silica-Gel Incorporated Biosynthesized-Silver Nanoparticles for Sustainable Antimicrobial Treatment of Brackish Water Aquaculture

Treatment of brackish water from pathogenic microbes is crucial for sustainable aquaculture production and preventing the spread of infectious diseases. However, the treatment of brackish water is still challenging due to the high salinity and the high antimicrobial resistance. Here, we exploit a facile and effective approach to synthesize silica gel embedded with silver nanoparticles (7–48 nm) for broad-spectrum antimicrobial activity. The incorporation of silver nanoparticles into silica gel (AgNPs@SG) is confirmed by flame atomic absorption spectrometry, X-ray diffraction, N2 physisorption, and transmission electron microscopy. The AgNPs@SG material exhibits wide-spectrum antimicrobial activity against the studied microorganisms (Pseudomonas aeruginosa, Escherichia coli, and Candida albicans) due to preventing the aggregation of silver nanoparticles and their effective contact with the microorganisms. Most importantly, the applicability of the synthesized AgNPs@SG for the microbial treatment of brackish water is investigated on different water samples collected from Manzala Lake. Remarkably, the amount of viable bacteria in the brackish water decreases by about 93% using AgNPs@SG material that not only combats antibiotic-resistant strains but also works under harsh conditions such as multiple-source contamination, high eutrophic state, and salinity.

Fungicidal activity of human antimicrobial peptides and their synergistic interaction with common antifungals against multidrug-resistant Candida auris.

Emergence of Candida auris, a multidrug-resistant yeast, demonstrates the urgent need for novel antifungal agents. Human antimicrobial peptides (AMPs) are naturally occurring molecules with wide spectrum antimicrobial activity, particularly against a variety of fungi. Therefore, this study examined the antifungal activity of seven different human AMPs against C. auris following the CLSI guidelines. The antifungal activity was further assessed using time kill curve and cell viability assays. For combination interaction, effectiveness of these peptides with three antifungals, fluconazole, amphotericin B, and caspofungin was done following standard protocols. To elucidate the antifungal mechanism, the effects of peptides on membrane permeability were investigated using propidium iodide staining method and confocal imaging. Antifungal susceptibility results showed that all the examined peptides possessed fungicidal effect against C. auris at different levels, with human β-defensin-3 being the most potent antifungal with MIC values ranging from 3.125 to 12.5µg/ml. Time kill curves further confirmed the killing effect of all the tested peptides. Viability assay showed a significant decrease in the percentage of viable cells exposed to different inhibitory and fungicidal concentrations of each peptide (p < 0.01). Furthermore, peptides showed mostly synergistic interaction when combined with conventional antifungal drugs, with caspofungin showing 100% synergy when combined with different AMPs. As antifungal mechanism, peptides disrupted the membrane permeability at concentrations that correlated with the inhibition of growth. Overall, the findings of this study point towards the application of the tested peptides as a monotherapy or as a combination therapy with antifungal drugs to treat multidrug-resistant C. auris infections.

Synthesis and antimicrobial studies of nano-copper doped carbon substrates; activated carbon, reduced graphene oxide, and carbon nanofiber

Copper oxides (CuxO) have received considerable attention as a result of their biological activity. Nanoparticles (NPs) of CuxO attached to different substrates exhibit a wide spectrum of antimicrobial activity against bacteria and viruses, with similar properties to silver. The antimicrobial activity of CuxO-NPs doped on distinctive carbon materials was investigated for three carbon substrates: apricot stone activated carbon (AAC), reduced graphene oxide (rGO) and carbon nanofiber (CNF). The CuxO-NPs (5 wt%) doped AAC and rGO substrates were prepared by impregnation of copper nitrate followed by a thermal treatment process, while a similar weight of CuxO-NPs doped CNF was fabricated by electrospinning copper nitrate with polyacrylonitrile precursor, followed by carbonization. The CuxO species and chemical functions were characterized by X-ray diffraction and Fourier transform infrared spectroscopy, respectively. Surface morphology was measured using scanning electron microscopy. The antimicrobial activities of the substrates were evaluated by inhibition zone measurement of Staphylococcus aureus and Escherichia coli. The results demonstrated significant inhibition distances for different carbon substrates. Interestingly, CuxO-NPs doped over both AAC and rGO surfaces revealed clear zones against bacteria, whereas the inhibition zone was not recorded for CuxO-NPs doped over a CNF substrate. Various parameters such as carbon substrates, particle size, and copper oxide species were investigated.

Eco-Friendly Solution Based on Rosmarinus officinalis Hydro-Alcoholic Extract to Prevent Biodeterioration of Cultural Heritage Objects and Buildings.

Biodeterioration of cultural heritage is caused by different organisms capable of inducing complex alteration processes. The present study aimed to evaluate the efficiency of Rosmarinus officinalis hydro-alcoholic extract to inhibit the growth of deteriogenic microbial strains. For this, the physico-chemical characterization of the vegetal extract by UHPLC–MS/MS, its antimicrobial and antibiofilm activity on a representative number of biodeteriogenic microbial strains, as well as the antioxidant activity determined by DPPH, CUPRAC, FRAP, TEAC methods, were performed. The extract had a total phenol content of 15.62 ± 0.97 mg GAE/mL of which approximately 8.53% were flavonoids. The polyphenolic profile included carnosic acid, carnosol, rosmarinic acid and hesperidin as major components. The extract exhibited good and wide spectrum antimicrobial activity, with low MIC (minimal inhibitory concentration) values against fungal strains such as Aspergillus clavatus (MIC = 1.2 mg/mL) and bacterial strains such as Arthrobacter globiformis (MIC = 0.78 mg/mL) or Bacillus cereus (MIC = 1.56 mg/mL). The rosemary extract inhibited the adherence capacity to the inert substrate of Penicillium chrysogenum strains isolated from wooden objects or textiles and B. thuringiensis strains. A potential mechanism of R. officinalis antimicrobial activity could be represented by the release of nitric oxide (NO), a universal signalling molecule for stress management. Moreover, the treatment of microbial cultures with subinhibitory concentrations has modulated the production of microbial enzymes and organic acids involved in biodeterioration, with the effect depending on the studied microbial strain, isolation source and the tested soluble factor. This paper reports for the first time the potential of R. officinalis hydro-alcoholic extract for the development of eco-friendly solutions dedicated to the conservation/safeguarding of tangible cultural heritage.

An Extensive Review on Production, Purification, and Bioactive Application of Different Classes of Bacteriocin

Lactic Acid Bacteria (LAB) synthesize various metabolites during their growth phase and are Generally Recognized as­­ Safe (GRAS) and Qualified Presumption of Safety (QPS). Ribosomally synthesized Antimicrobial Peptides (AMP) or Bacteriocins from the genera of Lactic Acid Bacteria and other prokaryotic genera are cationic, heat-stable, amphiphilic and the membrane permeabilizing peptides built with an excess amount of lysyl and arginyl residues. Antimicrobial compounds produced by LAB depend on the physical and biological conditions of microbial culture. Different classes of bacteriocin are produced by both Gram-positive and Gram-negative bacteria. The production of bacteriocin is influenced by various environmental factors. Bacteriocin has a wide variety of applications in various fields. The application spectrum of bacteriocins can be expanded in various domains such as food processing, biomedical, and personal care due to the increase in the number of newly discovered bacteriocins. Bacteriocins acquire a wide spectrum of antimicrobial activity with minimal level of cytotoxicity. In addition, bacteriocins were studied for their anticancer activity against different cancer cell lines. Selective binding of bacteriocins (cationic) towards cancer cells (anionic) increases the cytotoxicity of cancer cells. Bacteriocin peptides initiate necrosis by communicating with the cell surface which selectively targets and kills the cells with tumor formation and does not cause any damage to the normal healthy cells. In this review, the bacteriocins synthesized from lactic acid bacteria along with their interaction with cancer cell lines and other applications are discussed along with a few examples of other bioactive compounds produced by LAB.

Antibacterial activity of cationic amphiphil conjugates with ciprofloxacin

The aim: Design and synthesis of new compounds with antibacterial activity. Determination of the minimum inhibitory and minimum bactericidal concentration of conjugates of cationic amphiphiles based on quaternary salts of 1,4-diazabicyclo[2.2.2]octane with ciprofloxacin. Materials and methods: The article is dedicated to the synthesis and primary assessment of antibacterial activity in vitro of conjugates of cationic amphiphiles based on quaternary salts of 1,4-diazabicyclo[2.2.2]octane with ciprofloxacin against gram-negative and gram-positive microorganisms. Results: The present work provides hybrid structures which include the widely used antibiotic ciprofloxacin and tetra-cationic DABCO derivatives. The last ones previously showed a wide spectrum of antimicrobial activity as well as primary studies of their antibacterial activity against gram-positive and gram-negative microorganisms in vitro. There was a high in vitro antibacterial activity against gram-negative pathogens, moderate against Staphylococcus aureus and low against Enterococcus faecalis. Conclusions: A range of amphiphilic polycationic compounds based on quaternary salts of 1,4-diazabicyclo[2.2.2]octane (DABCO) was synthesized and their biological activity was studied. The compounds have demonstrated high antibacterial activity. We assume that they can serve as a basis for the development of new antibacterial drugs.

SUBSTANTIATION OF THE ELECTROLYTE COMPOSITION IN THE ELECTROCHEMICAL SYNTHESIS OF PEROXYLIC ACID

lactic acid (PLA) is a strong disinfectant with a wide spectrum of antimicrobial activity. Its widespread use is hampered by the lack of an electrochemical technology for PLA synthesis, which will make it possible to develop local electrochemical generators for the production of disinfectants. There is no information about the standard potential of the СН3СH(OH)С(=О)ОН « СН3СH(OH)С(=О)ООН system, both in reference literature and professional scientific publications. It has been shown that the electrochemical synthesis of PLA will be combined with the processes of oxygen release and the formation of hydrogen peroxide. To inhibit side processes, an additive to a solution of lactic acid 0.5 mol dm-3 H2SO4 was used. The adsorption of sulfate ions leads to the displacement of a certain proportion of water molecules outside the boundaries between the phase boundaries. An almost 2-fold increase in the anodic current density was also noted at the potentials of electrochemical synthesis of peroxide compounds. It has-been found that a lactic acid molecule is integrated into the structure of the near-electrode layer with a carboxyl group directed towards the anode surface. The inflection of the current-voltage curve, at potentials more positive than 1.70...1.75 V, indicates the course of the combined processes of the formation of peroxide compounds, proceeding with a significant inhibition of the oxygen reaction at the Pt/PtO2 anode. The release of oxygen under these conditions occurs due to the formation and destruction of H2O2. The potential difference between the forward and reverse runs of the current-voltage curve indicates a significant effect of lactic acid on the adsorption processes on the anode surface. The results obtained confirmed the relevant the choice of the Pt/PtO2 anode for the electrochemical synthesis of PLA. The characteristics of the electrolyte for the electrochemical synthesis of PLA has been defined: 2 mol dm-3 of lactic acid, 0.5 mol dm-3 of sulfuric acid.

Use of cefepime/sulbactam in the treatment of infections caused by carbapenem-resistant bacteria

Cefepime/sulbactam is a combined antibiotic with a wide spectrum of antimicrobial activity, including cefepime, the fourth-generation cephalosporin, and sulbactam, the beta-lactamase inhibitor, in a 1:1 ratio. Cefepime/sulbactam has a bactericidal effect: it causes a disorder in cell wall synthesis due to blockade of transpeptidase and a disorder in the formation of cross-links in peptidoglycan [1]. Today, the problem of antibiotic resistance is growing rapidly. In the WHO list, a critically high level of priority for the development of new antibiotics is occupied by infections caused by ESBL-producing gram-negative bacteria that are resistant to cephalosporins, as well as carbapenem-resistant Enterobacterales, Acinetobacter baumannii and Pseudomonas aeruginosa [2]. Infections caused by multiresistant bacteria are characterized by a longer course, require prolonged hospitalization, are very difficult to treat with modern antibacterial drugs, and increase the risk of death [3]. In this regard, a deeper study of the action of individual antibacterial drugs and their combination with β-lactamase inhibitors in the treatment of diseases caused by multiresistant microorganisms is crucial.