Reference Strains Of Bacteria Research Articles

Antibacterial properties of distilled cow’s urine on bacterial species from clinical specimens

Introduction and Aim: In Ayurveda, cow's urine has been reported to have many therapeutic values. The raising trend in antibacterial resistance is a cause of concern and demands an alternative therapeutic agent. Hence, the present study aims to know the antibacterial properties of urine from cows on clinical and reference strains of bacteria. Materials and Methods: The present in vitro experimental study, used agar dilution method to know the Minimum Inhibitory Concentration (MIC) of cow’s urine distillate (CUD) on few reference bacterial strains and Enterococcus faecalis, Staphylococcus aureus, Salmonella Typhi, Escherichia coli, and S. Paratyphi A isolated from clinical samples. Resistance and sensitivity of these isolates to routinely used antibiotics was studied by Kirby Bauer’s disk diffusion method. Results: MIC of CUD for different standard bacterial strains varied from 250 to 500?l/ml. Among the clinical isolates, all Salmonella Typhi, 85% of S. Paratyphi A, 60% of E. coli, 80% of the S. aureus, 64.28% S. aureus were resistant to methicillin (MRSA) and 24% of E. faecalis were killed by 500?l/ml of CUD. Clinical strains of bacteria, susceptible to routinely used antibiotics, were also found to be susceptible to CUD and showed a concentration-dependent inhibitory effect. Multi drug resistant strains of nine MRSA, one E. faecalis and two E.coli were also susceptible to 500?l/ml concentration of CUD. Conclusion: CUD can be considered as an alternative anti-bacterial agent for multi-drug resistant bacterial pathogens as it showed concentration dependent inhibitory effect on both Gram-positive and Gram-negative pathogenic bacteria.

Silver Nanoparticles as Chlorhexidine and Metronidazole Drug Delivery Platforms: Their Potential Use in Treating Periodontitis.

PurposePeriodontal disease (PD), defined as oral inflammation caused by dental plaque, is an emerging problem. PD may lead to tooth loss, and treatment options are limited. In this study, we designed, synthesized, and characterized silver nanoparticles (AgNPs) conjugated with chlorhexidine (AgNPs-CHL) or metronidazole (AgNPs-PEG-MET) to determine whether they can be used to treat PDs.Materials and MethodsAgNPs were synthesized and characterized by transmission electron microscopy, UV-vis spectrometry, thermogravimetric analyses, and dynamic light scattering. We determined the safety and the antimicrobial and anti-inflammatory properties of synthesized AgNPs in an in vitro model of periodontitis. Antimicrobial properties were determined by measuring the minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) on reference strains of bacteria and fungi. Human gingival fibroblast (HGF-1), murine macrophage (RAW264.7) and human foetal osteoblast (hFOB1.19) cells were used in the study. Lipopolysaccharide (LPS) was used to induce inflammation. Cytokine levels were measured using an enzyme-linked immunosorbent assay; metalloproteinase expression was measured using Western blotting.ResultsThe synthesized AgNPs were spherical and narrow-dispersed with an average diameter of 13.4 nm ± 3.0 nm in the case of AgNPs-CHL and 3.72 nm ± 0.72 nm in the case of AgNPs-PEG-MET. Both types of AgNPs were active against bacteria and fungi. AgNPs-CHL proved to be a more potent antimicrobial agent, although they were more cytotoxic than AgNPs-PEG-MET; however, both demonstrated beneficial properties in nontoxic concentrations. AgNPs-CHL and AgNPs-PEG-MET decreased the production of proinflammatory cytokines IL-1β, IL-6, IL-8 and TNFα. Both agents also decreased the levels of metalloproteinases MMP3 and MMP8, which may indicate that they will inhibit tissue degradation.ConclusionAgNPs-CHL and AgNPs-PEG-MET may be possible therapeutic options for PD, as they have antibacterial and anti-inflammatory properties. However, to fully understand the potential of AgNPs, our in vitro findings must be evaluated in an in vivo model.

Enantioselectivity of Chiral Derivatives of Xanthones in Virulence Effects of Resistant Bacteria.

Antimicrobial peptides are one of the lines of defense produced by several hosts in response to bacterial infections. Inspired by them and recent discoveries of xanthones as bacterial efflux pump inhibitors, chiral amides with a xanthone scaffold were planned to be potential antimicrobial adjuvants. The chiral derivatives of xanthones were obtained by peptide coupling reactions between suitable xanthones with enantiomerically pure building blocks, yielding derivatives with high enantiomeric purity. Among 18 compounds investigated for their antimicrobial activity against reference strains of bacteria and fungi, antibacterial activity for the tested strains was not found. Selected compounds were also evaluated for their potential to inhibit bacterial efflux pumps. Compound (R,R)-8 inhibited efflux pumps in the Gram-positive model tested and three compounds, (S,S)-8, (R)-17 and (R,S)-18, displayed the same activity in the Gram-negative strain used. Studies were performed on the inhibition of biofilm formation and quorum-sensing, to which the enantiomeric pair 8 displayed activity for the latter. To gain a better understanding of how the active compounds bind to the efflux pumps, docking studies were performed. Hit compounds were proposed for each activity, and it was shown that enantioselectivity was noticeable and must be considered, as enantiomers displayed differences in activity.

Antimicrobial Activity of Phytic Acid: An Emerging Agent in Endodontics.

BackgroundPhytic acid (IP6) is a promising and emerging agent, and because of its unique structure and distinctive properties, it lends itself to several applications in dentistry. Recently, IP6 was proposed as a potential chelating agent in endodontics. However, there is limited knowledge regarding its antimicrobial and antibiofilm effectiveness. The aims of this study, were therefore to evaluate the antimicrobial and antibiofilm activities of IP6 against a range of microbial species and compare these with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl). The contact time required for IP6 to exert its bactericidal effect on Enterococcus faecalis was also determined.MethodsThe inhibitory and biocidal activities of IP6, EDTA and NaOCl were assessed using a broth microdilution assay against 11 clinical and reference strains of bacteria and a reference strain of Candida albicans. The contact time required for various IP6 concentrations to eliminate planktonic cultures of E. faecalis was determined using a membrane filtration method according to BS-EN-1040:2005. IP6 bactericidal activity was also evaluated using fluorescent microscopy, and the antibiofilm activity of the test agents was also determined.ResultsIP6 was biocidal against all tested microorganisms. At concentrations of 0.5%, 1% and 2%, IP6 required 5 min to exert a bactericidal effect on E. faecalis, while 5% IP6 was bactericidal after 30 s. IP6 also eradicated biofilms of the tested microorganisms. In conclusion, IP6 had notable antimicrobial effects on planktonic and biofilm cultures and exhibited rapid bactericidal effects on E. faecalis. This research highlighted, for the first time the antimicrobial and antibiofilm properties of IP6, which could be exploited, not only in dental applications, but also other fields where novel strategies to counter antimicrobial resistance are required.

Influence of Carbohydrate Residues on Antibacterial Activity of Vancomycin

This paper presents synthesis of vancomycin derivatives modified with selected 1- and 2-aminoalditols to carboxylic function and 2,5-anhydro-D-mannose and D-talose to amino function of vancosamine via reductive alkylation. MIC and MBC of these derivatives were determined for reference strains of bacteria: Staphylococcus aureus ATCC 25923, ATCC 6538, ATCC 6538/P, S. epidemidis ATCC 14490, E. faecium PCM 1859, E. faecalis PCM 2673, S. pyogenes PCM 465, and S. pneumonia ATCC 49619 and compared with the activity of vancomycin and its aglycone. Our findings confirm that sugar fragments can play an important role in the mechanism of interaction of vancomycin with bacterial cell wall peptidoglycan.

АНТИБАКТЕРИАЛЬНАЯ, ПРОТИВОГРИБКОВАЯ, АНТИОКСИДАНТНАЯ АКТИВНОСТЬ И СОДЕРЖАНИЕ ПОЛИФЕНОЛОВ В ЛУКОВИЦЕ И НАДЗЕМНЫХ ЧАСТЯХ ALLIUM SCHUGNANICUM

Objective: То study of antibacterial, antifungal and antioxidant activity, and content of polyphenols in the bulb and aerial parts of an endemic species of onion A. schugnanicum. Methods: An ethanol-based extract was prepared from fresh plants. Total polyphenolic content (Folin) and ABTS antioxidant capacity assays were used to characterized extracts. Extracts obtained from bulbs, peduncle, and seeds demonstrated antibacterial activity against the reference Staphylococcus aureus (ATCC 4929), Pseudomonas aeruginosa (ATCC 4930) and Klebsiella pneumoniae (ATCC 4927) strains, as well as against the hospital strains of the same types of bacteria, i.e. strains isolated from inpatient surgical patients. Results: The study found that ethanol extracts obtained from all organs of A. schugnanicum exhibit high inhibitory activity against the hospital and reference strains. In relation to reference then to hospital strains ethanol extracts were more active. The greatest bactericidal effect on both strains was exhibited by the bulb extracts. The extracts did not inhibit the growth of Escherichia coli. Fungicidal action characterized by growth inhibition zone of bulb and seeds, respectively. The extract obtained from the peduncle of this plant exhibited smaller inhibitory activity. The antioxidant capacity of A. schugnanicum different parts are shown in all the parts had a large antioxidant activity with dominating antioxidant capacity in seeds. The highest polyphenol level was found in the bulb. Conclusions: The study showed that A. schugnanicum may be a prospective species for developing botanical therapeutics. Keywords: Allium schugnanicum, medicinal plants, growth inhibition, extracts, antioxidant activity, hospital strains of bacteria, reference strains of bacteria

Novel functionalized β-nitrostyrenes: Promising candidates for new antibacterial drugs

The process of searching for new antibacterial agents is more and more challenging due to the increasing drug resistance which has become a major concern in the field of infection management. Our study presents a synthesis and characterization by IR, UV, 1H NMR and 13C NMR spectra of a homogenous series of 1-EWG functionalized 2-aryl-1-nitroethenes which could prove good candidates for the replacement of traditional antibacterial drugs In vitro screening against a panel of the reference strains of bacteria and fungi and their cytotoxicity towards cultured human HepG2 and HaCaT cells was performed. Antimicrobial results indicated that four of the synthesized compounds exhibited a significant antimicrobial activity against all tested reference bacteria and fungi belonging to yeasts with a specific and strong activity towards B. subtilis ATCC 6633. Two of these compounds had no detectable cytotoxicity towards the cultured human cell lines, making them promising candidates for new antibacterial drugs.

СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА АНТИБАКТЕРИАЛЬНОЙ АКТИВНОСТИ НЕКОТОРЫХ РАСТЕНИЙ, ПРОИЗРАСТАЮЩИХ В ЦЕНТРАЛЬНОЙ ЧАСТИ РЕСПУБЛИКИ ТАДЖИКИСТАН

Objective: To evaluate the spectrum of antibacterial activity of plants growing in the central part of the Republic of Tajikistan. Methods: The antibacterial properties of 18 plant species from the 14 families were studied. The extract samples on dry filter discs were prepared according to the method developed at Rutgers University. Screens-to-Nature (STN) and disc diffusion (DD) methods were used to assess antimicrobial properties of the extracts. The antimicrobial activity of plant extracts was determined against four types of pathogenic standard museum strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, as well as by using the same types of microorganisms isolated from inpatients (the hospital strains). Results: Ethanol extract from leaves of Artemisia absinthium demonstrated a broad-spectrum high degree of antimicrobial activity against both reference and hospital strains of S. aureus, P. aeruginosa and E. coli. The Morus nigra extract also showed broad-spectrum activity, however overall antibacterial activity was lower than in A. absinthium. In general, tested extracts were less effective against E. coli. None of the 18 tested extracts showed activity against K. pneumoniae. Conclusion: Artemisia absinthium and Morus nigra have a broad-spectrum antimicrobial effect and differ only in the degree of activity. The extracts of Amaranthus tricolor and Arctium tomentosum, Indigofera tinctoria, Punica granatum were characterized by a somewhat narrower spectrum of action. Mentha arvensis and Allium suworowii had approximately the same degree of inhibitory ability. Keywords: Plants, growth inhibition, extracts, hospital strains of bacteria, reference strains of bacteria.

Essential oils as potential anti-staphylococcal agents

Abstract Antibiotic therapy of staphylococcal mastitis is characterized by significantly lower cure rates compared to infections caused by other microorganisms. Thus, it is necessary to search for new, alternative, non-antibiotic agents that are effective in the eradication of these bacteria. The aim of our research was to investigate the antimicrobial, especially anti-staphylococcal potential of a large collection (n=36) of essential oils (EOs). Investigation of the antimicrobial activity of tested oils was determined by using a serial, twofold dilution method in 96-wells microtiter plates under conditions recommended by the Clinical and Laboratory Standards Institute (CLSI). The preliminary analysis revealed that six oils, namely: Manuka, Thyme, Geranium, Cedar, Cinnamon (from bark) and Patchouli exhibited the highest activity against reference strains of bacteria. Significant anti-staphylococcal potential of these oils has been also confirmed for a group of 18 Staphylococcus aureus, 8 Staphylococcus epidermidis and 5 Staphylococcus xylosus strains isolated from cases of bovine mastitis. Especially high activity was observed for Cedar, Patchouli, Thyme and Manuka oils. The MIC (Minimal Inhibitory Concentration) values for Patchouli oil were in the concentrations range of 0.01 to 0.313% (v/v). The three other oils inhibited the growth of staphylococci isolated from mastitis in the concentrations range of 0.01 to 0.625% (v/v). Oils isolated from Cinnamomum cassia and Pelargonium graveolens revealed a bit lower, but still satisfactory activity (MIC values in the concentrations range of 0.02 to 1.25% (v/v) and from 0.078 to 1.25% (v/v), respectively). In many cases a slightly higher concentration of oils was required to obtain the bactericidal effect in comparison to growth inhibition. The time – kill kinetic assay revealed that the bactericidal effect was achieved after two hours incubation of the reference strain S. aureus PCM 2051 cells with Thyme oil at concentration equal to 2xMIC (1.25% (v/v)) or MIC (0.625% (v/v)). A slightly lower activity was observed in the case of Cinnamon oil, the bactericidal effect was achieved after 8 hours of incubation. The results of our research clearly indicate that some essential oils exhibit a promising antimicrobial activity and can be considered as alternative antistaphylococcal agents.

Characterization of Apis mellifera Honey of Different Botanical and Geographical Origins in Egypt

Seven honey types identified botanically in terms of their floral origin (clover, Cedrus, citrus, banana, cotton, Brazilian pepper and sun flower), and their geographical regions during 2016-2017 have been characterized in comparison with artificial honey. Characterization of honeys was based on their physicochemical properties, antibacterial & antifungal activity, heavy metal contents and multi-pesticides residues using quantitative analysis methods. All honeys tested were natural and give negative results for adulteration tests. Sun flower and cotton honeys showed the highest sucrose content regardless the artificial honey sucrose content (74 ±1 % (g/100 g). The water content and pH value of different honeys investigated were within the standard limits 20g/100g and 3.4-6.1, respectively. Hydroxymethylfurfural (HMF) content in most honeys was below the maximum allowable limit (MAL) (40 mg/kg) in honey, except for banana honey. None of the honeys tested showed any antifungal activity. Artificial honey showed no growth inhibition against reference strains of bacteria and fungi tested. Metal content of Fe, Zn, Pb, Cu in Egyptian honeys fulfill the (MAL) described in the standard codex for honey except for Cd with concentrations exceeding the MAL (0.05 mg/kg) in most types of honey, except for artificial honey. Malathion, chlorpyrifos and tau-fluvalinate were the most frequently detected (25%, n=2) insecticides in honey samples. It can be concluded that the best Egyptian honeys tested in terms of antibacterial activity were Brazilian pepper honey followed by Cedrus honey. The data obtained are extremely important for the public, health officials for medical and nutritional applications of honey.

Chemical compounds and antimicrobial activity of petitgrain (Citrus aurantium L. var. amara) essential oil

Summary Introduction: Due to its low cost and easy availability on the market, the petitgrain oil is commonly used in food, cosmetics, and aromatherapy. Objective: The examination of chemical composition and antibacterial activity of commercial petitgrain oil. Methods: Identification of chemical components of the petitgrain oil was performed by gas chromatography (GC). The minimum inhibitory concentrations (MIC) and minimum bactericidal/fungicidal concentrations (MBC/MFC) were determined using macrodilution method for the reference strains of bacteria and fungi. Results: Twenty components were identified. The petitgrain oil contained mostly oxygenated monoterpene hydrocarbons (98.01%), and the main components included linalyl acetate (48.06%) and linalool (26.88%). The MIC/MBC of the petitgrain oil for bacteria was in the range of 0.63-5.0/1.25-5.0 mg/ml and for fungi in the range of 1.25-40/5.0-80 mg/ml. Conclusion: The petitgrain oil had higher antibacterial activity than antifungal activity. Bacillus subtilis among the tested bacteria and Aspergillus niger and Penicillium expansum among the fungi were found to be highly inhibited by the petitgrain oil.

Cystatin C peptidomimetic derivative with antimicrobial properties as a potential compound against wound infections

A peptidomimetic called A20 (Cystapep 1) structurally based upon the N-terminal fragment of human cystatin C is known to have strong antibacterial properties. A20 is characterized by high activity against several bacterial strains often isolated from infected wounds, including methicillin-resistant S. aureus (MRSA). In this work we wanted to explore the therapeutic potential of A20 in the treatment of wound infections. We examined, cytotoxicity, allergenicity and impact of A20 on the proliferation and viability of human keratinocytes. Furthermore, the previously described antimicrobial action of A20has been confirmed here with reference strains of bacteria and extended by several other species. The A20 was highly active against Gram-positive bacteria with minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) between 8 and 128μg/mL. A20 did not affect proliferation of primary human keratinocytes in concentrations up to 50μg/mL. At the same time, it did not activate Peripheral Blood Mononuclear Cells (PBMCs), including basophils or neutrophils in vitro. Interestingly A20 was found to display immunomodulatory functions as it influences the production of Th2 cytokines (IL-4 and IL-13) by activated PBMCs. It was also resistant to degradation for at least 48h in human plasma. The results indicate that A20 is effective against the multiantibiotic-resistant bacteria and has a high safety profile, which makes it a promising antimicrobial drug candidate.

A New Catalog of Microbiological Tools for Women's Infectious Disease Research.

Genitourinary infections pose serious health risks. But, little is known about how genitourinary bacteria attach, maintain colonization, compete for resources, and cause pathology. In this issue, we introduce a new set of 62 genitourinary reference strains of bacteria and their genomes to spur experimental research on infectious diseases that impact women.

Hydrazide-hydrazones of 3-methoxybenzoic acid and 4-tert-butylbenzoic acid with promising antibacterial activity against Bacillus spp

A series of 28 hydrazide-hydrazones of 3-methoxybenzoic and 4-tert-butylbenzoic acid were synthesized and screened in vitro against the panel of reference strains of bacteria and fungi with the use of the broth microdilution method according to EUCAST and CLSI guidelines. Five of the synthesized compounds were found to exhibit high bacteriostatic or bactericidal activity against Gram-positive bacteria. The antimicrobial activity of compounds 13, 14, and 16 against Bacillus spp. was higher than that of commonly used antibiotics, like cefuroxime or ampicillin.

Crystalline pyrazine-2-amidoxime isolated by diffusion method and its structural and behavioral analysis in the context of crystal engineering and microbiological activity

The physicochemical characterizations of PAOX were obtained both in solid-state and solution, and its two anti-conformers were observed in the X-ray. Its antimicrobial properties were tested against reference strains of bacteria and yeast.

Synthesis of Novel Derivatives of Imidazo[2,1-c][1,2,4]Triazine from Biologically Active 4-Arylidene-2-Hydrazino-1-Phenyl-1H-Imidazol-5(4H)-Ones and Evaluation of their Antimicrobial Activity

4-Arylidene-2-hydrazino-1-phenyl-1H-imidazolin-5(4H)-ones were synthesised and used as key intermediates for the synthesis of novel imidazo[2,1-c][1,2,4]triazine derivatives. The new imidazo[2,1-c][1,2,4]triazine derivatives were obtained via the reaction of the hydrazino derivatives with pyruvic acid, chloroacetyl chloride and phenacyl bromide derivatives respectively. Structures of the newly synthesised compounds were confirmed using spectral data as well as elemental analysis. Seven compounds were evaluated for their antimicrobial activity with minimum inhibitory concentration (MIC) values against several reference strains of bacteria and fungi, with ampicillin, gentamicin and amphotericin B used as comparison drugs. It was observed that most of the evaluated compounds showed high antibacterial as well as antifungal activities. 6-(4-Chlorobenzylidene)-4-(4-methylphenyl)-8-phenyl-6,8-dihydroimidazo-[2,1-c][1,2,4] triazin-7(2H)-one was the most potent compound with high inhibition zones and low MIC values.

Coordination chemistry of pyrazine derivatives analogues of PZA: design, synthesis, characterization and biological activity

A novel Ru(iii) complexes were synthesized and characterized. Their stabilities were discussed in terms of aqueous and MeCN solutions. Antimicrobial properties of complexes studied were characterized against reference strains of bacteria and yeast.

Synthesis and Evaluation of Selected Benzimidazole Derivatives as Potential Antimicrobial Agents.

A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1H-benzo[d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal activity against the selected fungal strains. They displayed equivalent or greater potency in their MIC values than amphotericin B. The 5-halobenzimidazole derivatives could be considered promising broad-spectrum antimicrobial candidates that deserve further study for potential therapeutic applications.

Sterilization of bacteria suspensions and identification of radicals deposited during plasma treatment

Abstract In this paper we will present results for plasma sterilization of planktonic samples of two reference strains of bacteria, Pseudomonas aeruginosa ATCC 27853 and Enterococcus faecalis ATCC 29212. We have used a plasma needle as a source of non-equilibrium atmospheric plasma in all treatments. This device is already well characterized by OES, derivative probes and mass spectrometry. It was shown that power delivered to the plasma is bellow 2 W and that it produces the main radical oxygen and nitrogen species believed to be responsible for the sterilization process. Here we will only present results obtained by electron paramagnetic resonance which was used to detect the OH, H and NO species. Treatment time and power delivered to the plasma were found to have the strongest influence on sterilization. In all cases we have observed a reduction of several orders of magnitude in the concentration of bacteria and for the longest treatment time complete eradication. A more efficient sterilization was achieved in the case of gram negative bacteria.

Biological and surface-active properties of double-chain cationic amino acid-based surfactants

Cationic amino acid-based surfactants were synthesized via solid phase peptide synthesis and terminal acylation of their α and ε positions with saturated fatty acids. Five new lipopeptides, N-α-acyl-N-ε-acyl lysine analogues, were obtained. Minimum inhibitory concentration and minimum bactericidal (fungicidal) concentration were determined on reference strains of bacteria and fungi to evaluate the antimicrobial activity of the lipopeptides. Toxicity to eukaryotic cells was examined via determination of the haemolytic activities. The surface-active properties of these compounds were evaluated by measuring the surface tension and formation of micelles as a function of concentration in aqueous solution. The cationic surfactants demonstrated diverse antibacterial activities dependent on the length of the fatty acid chain. Gram-negative bacteria and fungi showed a higher resistance than Gram-positive bacterial strains. It was found that the haemolytic activities were also chain length-dependent values. The surface-active properties showed a linear correlation between the alkyl chain length and the critical micelle concentration.