Sensitive Bacterial Strains Research Articles

Nanocarrier-Mediated Dermal Drug Delivery System of Antimicrobial Agents for Targeting Skin and Soft Tissue Infections.

Antimicrobial resistance in disease-causing microbes is seen as a severe problem that affects the entire world, makes therapy less effective, and raises mortality rates. Dermal antimicrobial therapy becomes a desirable choice in the management of infectious disorders since the rising resistance to systemic antimicrobial treatment frequently necessitates the use of more toxic drugs. Nanoparticulate systems such as nanobactericides, which have built-in antibacterial activity, and nanocarriers, which function as drug delivery systems for conventional antimicrobials, are just two examples of the treatment methods made feasible by nanotechnology. Silver nanoparticles, zinc oxide nanoparticles, and titanium dioxide nanoparticles are examples of inorganic nanoparticles that are efficient on sensitive and multidrug-resistant bacterial strains both as nanobactericides and nanocarriers. To stop the growth of microorganisms that are resistant to standard antimicrobials, various antimicrobials for dermal application are widely used. This review covers the most prevalent microbes responsible for skin and soft tissue infections, techniques to deliver dermal antimicrobials, topical antimicrobial safety concerns, current issues, challenges, and potential future developments. A thorough and methodical search of databases, such as Google Scholar, PubMed, Science Direct, and others, using specified keyword combinations, such as "antimicrobials," "dermal," "nanocarriers," and numerous others, was used to gather relevant literature for this work.

Surface-enhanced Raman spectroscopy for the rapid identification of fosfomycin resistant and sensitive strains of E. Coli

Development of rapid detection and discrimination technique for the antibiotic resistant and sensitive bacterial strains is required for this purpose, Surface-enhanced Raman spectroscopy (SERS) technique is considered to have great potential. To develop a fast and sensitive detection and discrimination methodology based on SERS technique along with chemometric tools for the differentiation among fosfomycin sensitive and resistant Escherichia coli (E. coli.) strains. In this research work, three E. Coli strains resistant to fosfomycin with three fosfomycin sensitive E. coli strains were characterized in which silver nanoparticles were employed as SERS substrate. Moreover, MATLAB 7.8 (2009a) was used for the preprocessing, baseline correction and normalization of SERS spectra. Using principal component analysis (PCA) and partial least squares discriminant analysis (PLSDA), several E. Coli strains were identified on the basis of their distinctive SERS spectral properties. The differentiating SERS spectral features which can be associated with the resistance and sensitivity against fosfomycin antibiotic, are obtained by comparing mean SERS spectrum of strains of resistant E. coli with sensitive E. coli strains. Chemometric techniques, such as principal components analysis, have been proven effective for qualitative analysis. Additionally, PLSDA was employed to classify the SERS spectra acquired from the pellets of several bacterial strains. SERS is a useful analytical method for quickly differentiating between E. Coli strains that are sensitive to fosfomycin and those that are resistant to it.

Formulation of Thermo-Sensitive In Situ Gels Loaded with Dual Spectrum Antibiotics of Azithromycin and Ofloxacin.

In situ gels have been developed as an innovative strategy to prolong corneal residence time and enhance drug absorption compared to traditional eye drops. Our study aimed to formulate an ophthalmic in situ gel with a combination of two thermosensitive poloxamers, P407 and P188, in an optimal ratio not only to increase the time of action but also to increase the solubility of selected antibiotics for the treatment of ophthalmic infections. Two BSC II class substances, Azithromycin and Ofloxacin, with different mechanisms of action, have been incorporated into the in situ gel system after determining their solubility. The antibiotics-loaded in situ gel formulation was evaluated for its clarity, pH, rheological properties, and gel characteristics of gelling time, temperature, and capacity. The formulation demonstrated satisfactory clarity, appropriate pH, effective gelation properties in simulated tear fluid, and suitable rheological characteristics. In addition, APIs release insight has been studied through a dissolution test, and the effectivity against sensitive and resistant bacterial strains has been proved through the antimicrobial study. Therefore, our in situ gel system based on thermosensitive poloxamers, with two hydrophobic antibiotics, AZM and OFX, can be considered a valuable approach for ophthalmic drug delivery with an enhancement of the antibiotics bioavailability through increasing the contact time with the ocular surface and enhancing patient compliance.

Red-Emitting Coumarin-Derived fluorescent probe for thiol detection and indirect recognition of β-Lactamase

Biothiols, comprising cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), play a pivotal role in maintaining the delicate redox balance essential for life processes, intricately intertwined with the well-being of living organisms. Deviations in their concentrations can precipitate a range of diseases. Herein, we presented a novel fluorescent probe, DIcou-DNBS, derived from coumarin, which possessed red emission and a substantial Stokes shift (122 nm), tailored for biothiol detection. DIcou-DNBS demonstrated rapid-responsiveness (6 min) towards Cys, Hcy and GSH with detection limits of 0.015 µM, 0.032 µM and 0.059 µM, respectively. Furthermore, its excellent biocompatibility enabled successful applications in biothiol fluorescence imaging of living cells and zebrafish. Beyond biothiol sensing, DIcou-DNBS leveraged its unique property to indirectly detect β-lactamases, making it a valuable tool in inhibitor screening and susceptibility testing of both sensitive (Staphylococcus aureus ATCC 29213) and resistant (Enterobacter cloacae ATCC 13047) bacterial strains. This assay system anticipates to furnish a potent instrument for visualization studies across biological and medical domains.

Evaluation of the antimicrobial activity and chickpea growth stimulation effects of green synthesized zinc oxide nanoparticles

Green synthesized nanoparticles are believed to alleviate the detrimental effects of chemical fertilizers and the multidrug resistance of various microbial strains. This study evaluates the use of bush tea-mediated zinc oxide nanoparticles (ZnO NPs) for chickpea fertilization and assesses their cytotoxicity, antioxidant and antibacterial activity. The study demonstrated that the application of ZnO NPs improved the number of leaves, nodules, biomass and yield of chickpea cultivars under glasshouse conditions. The authors suggest that biosynthesized ZnO NPs are a good plant growth stimulant. The control with no nanoparticles application, had higher values of photosynthetic rate and water use efficiency in the Desi genotype whereas for the Kabuli genotype, 25 mg/L showed higher values of stomatal conductance and transpiration efficiency, while 15 mg/L gave the highest water use efficiency and photosynthetic rate. Furthermore, the inhibitory activities of bacteria were reported in which E. coli and S. aureus were the most sensitive bacterial strains. The ZnO NPs also quenched free radicals that demonstrate antioxidant activity. Thus, they can be beneficial to both plants and humans as they reduce oxidative stress that can cause diseases. Furthermore, toxicity to cells was evaluated and ZnO NPs were less toxic to the studied cells with IC50 values of 16.17 µg/mL and 21.30 µg/mL against lung cancer and embryonic cell lines. Thus, the use of ZnO nanoparticles with antimicrobial activity could help fight against several diseases attacking humans and plants.

Evaluation of antibacterial and antifungal activities of Pistacia atlantica and Pistacia khinjuk

Medicinal plants are renowned for their various therapeutic properties, including antibacterial and antifungal activities. This study aimed to investigate the antibacterial and antifungal activities of P. atlantica and P. khinjuk. Hydroalcoholic extracts of P. atlantica and P. khinjuk were prepared to assess their antibacterial and antifungal activities. Standard strains of Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Aspergillus flavus were utilized for the evaluation of antibacterial and antifungal activities. The inhibitory effects of the extracts on the growth of bacterial and fungal strains were evaluated using minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) through a 96-well microplate analysis following CLSI guidelines. Our findings revealed that the MICs and MBCs of P. atlantica and P. khinjuk for bacterial strains ranged from 0 to 64 mg/mL. Additionally, the MIC and MFC values for fungal strains ranged from 16 to 64 mg/mL. The results indicated that Pseudomonas aeruginosa and Klebsiella pneumonia were the most sensitive bacterial strains to P. atlantica. Furthermore, Aspergillus flavus was identified as the most sensitive fungal strain to P. atlantica. In conclusion, these findings suggest that P. atlantica and P. khinjuk possess antibacterial and antifungal effects. The paper argues that these plant extracts could be used as a supplementary treatment alongside conventional antibacterial and antifungal drugs.

Antioxidant and antimicrobial activity of the endemic Mentha longifolia subsp. cyprica growing in Cyprus

Mentha longifolia subsp. cyprica (Heinr. Braun) Harley, endemic to Cyprus, is traditionally used to treat tonsillitis and as an inhalant for headaches. In this study, the essential oil components, antioxidant activity, total phenolic content of extracts, and antimicrobial activity of the essential oil and the extracts from the aerial parts of M. longifolia subsp. cyprica are reported for the first time. The essential oil profile was determined by GC and GC/MS, and 28 compounds were identified. The main components were pulegone (71.5 %), 1,8-cineole (9.5 %), menthone (5.0 %), and limonene (3.4 %). The methanol extract revealed the highest antioxidant activity (0.109 mg/ml) and phenolic content (60.9 ± 0.034 mg gallic acid/g extract) compared to the ethyl acetate (0.368 mg/ml, 24.3 ± 0.032 mg GAE/g extract) and n-hexane (1.737 mg/ml, 10.1 ± 0.023 mg GAE/g extract) extracts. The antimicrobial activity of the essential oil and extracts was screened for their antibacterial and anticandidal effects against selected microorganisms. Pseudomonas aeruginosa was the most sensitive bacterial strain to the tested samples (MIC, 500–1000 µg/ml). In contrast, better inhibition effects were shown against Candida species, with a MIC of 62.5 µg/ml against C. utilis. The results of this study may partially support the traditional use of M. longifolia subsp. cyprica and provide insight into an alternative species.

A stochastic dynamical model for nosocomial infections with co-circulation of sensitive and resistant bacterial strains.

Nosocomial infections (hospital-acquired) has been an important public health problem, which may make those patients with infections or involved visitors and hospital personnel at higher risk of worse clinical outcomes or infection, and then consume more healthcare resources. Taking into account the stochasticity of the death and discharge rate of patients staying in hospitals, in this paper, we propose a stochastic dynamical model describing the transmission of nosocomial pathogens among patients admitted for hospital stays. The stochastic terms of the model are incorporated to capture the randomness arising from death and discharge processes of patients. Firstly, a sufficient condition is established for the stochastic extinction of disease. It shows that introducing randomness in the model will result in lower potential of nosocomial outbreaks. Further, we establish a threshold criterion on the existence of stationary distribution and ergodicity for any positive solution of the model. Particularly, the spectral radius form of stochastic threshold value is calculated in the special case. Moreover, the numerical simulations are conducted to both validate the theoretical results and investigate the effect of prevention and control strategies on the prevalence of nosocomial infection. We show that enhancing hygiene, targeting colonized and infected patients, improving antibiotic treatment accuracy, shortening treatment periods are all crucial factors to contain nosocomial infections.

Antimicrobial Activity of Psidium guajava Aqueous Extract against Sensitive and Resistant Bacterial Strains.

The inappropriate use of antimicrobials, along with environmental conditions, can lead to the emergence of resistant microorganisms. The use of phytopharmaceuticals and herbal medicines has a positive impact and represents a promising alternative. Psidium guajava extracts have been widely reported to have antimicrobial potential; however, studies reporting their activity against resistant bacterial strains are scarce. Because of the emerging resistance, the aim of this study was to analyze the antimicrobial capacity of the aqueous extract of guava leaves against wild-type and resistant bacterial strains. The aqueous extract obtained from the leaves of P. guajava was evaluated by HPLC for the content of total phenolics and tannins, antioxidant activity, and chemical composition. The antimicrobial activity of the extracts was analyzed by the disk diffusion and broth microdilution methods. The results of the chemical analysis of the extracts showed total phenolics content of 17.02 ± 6.87 mg/g of dry extract, total tannin content of 14.09 ± 1.20 mg of tannic acid equivalents/g of dry extract, and moderate antioxidant capacity with an EC50 value of 140 µg/mL. Flavonoids are the major compounds (rutin, hesperidin, and quercetin), followed by phenolic acids. Disk diffusion test results showed the presence of inhibition halos for Gram-positive bacteria (Staphylococcus aureus, sensitive and resistant; Staphylococcus pseudintermedius, sensitive and resistant; and Streptococcus spp., beta-hemolytic), while for Gram-negative bacteria (Escherichia coli, sensitive and resistant), there was no inhibition in the tested concentration range. The Minimal Inhibitory Concentration was 6.8 mg/mL for all Gram-positive strains evaluated. The present study demonstrated the antimicrobial activity of the aqueous extract of P. guajava against sensitive and resistant Gram-positive bacteria. The better antimicrobial activity found in the present study compared with previously reported activity should be highlighted and may be related to the higher concentration of total phenolics present in the tested extract. Moreover, the content of tannins found suggests a species with high quality that produces tannins. These new findings suggest an innovative profile regarding therapeutic resources that can be adopted to combat resistant microbial strains.

Phytochemical and biocidal properties of Artemisia campestris subsp. campestris L. (Asteraceae) essential oil at the southern region of Algeria

Wormwood (Artemisia campestris subsp. campestris) is a perennial Asteraceae which is used in folk medicine in many places of the world. Even known as medicinal herb, this subspecies of A. campestris is not chemically characterized. Therefore, the aims of this study were to screen phytochemical, to characterize the essential oil of Artemisia campestris subsp.campestrisand to evaluatein vitro antibacterial and antifungal activity of these essential oil. Chemical analyses showed that wormwood contains mainly flavonoids, tannins and free saponins. Moreover, essential oil determination highlighted the presence of α and β pinene, β cymene and limonene which are known as biocidal compounds. For the antibacterial activity, the aromatogram method helped highlight the antibacterial activity of the essential oil of Artemisia against four bacteria Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae. This power is relatively low; the inhibition zones vary between 8 and 14,1 mm. The dilution method confirmed the results of the aromatogram method. The minimum inhibitory concentrations (MICs) obtained is between 0.031% and 0.125% respectively of 0.01 and 0.0413 mg/ml. The most sensitive bacterial strains are Pseudomonas aeruginosa and Klebsiella pneumoniae. Disk diffusion method also helped to highlight the essential oil antifungal power sagebrush country against mycelial growth of the tested strains especially Aspergillus niger. The zones of inhibition ranged from 22.5 to 24 mm where the values of MICs obtained are between 0.062% and 0.031% respectively representing 0.022 and 0.01 mg/ml. These results emphasized the potential use of the essential oil of A. campestris subsp. campestris as a preservative which is very promising for the food industry for its ability to prevent the oxidation of foods and reduce the growth of mycelial, which is responsible for food alteration.

Solvent System-Guided Extraction of Centaurium spicatum (L.) Fritch Provides Optimized Conditions for the Biological and Chemical Characteristics of the Herbal Extracts.

Spiked centaury (Centaurium spicatum) is a well-known medicinal plant from the Mediterranean region with various bioactivities, but there are no studies addressing the use of different solvent systems to improve its pharmacological potential. Nine extraction procedures were adapted to study the effects of solvent composition on the content of bioactive compounds in C. spicatum extracts and on corresponding bioactivities. Targeted metabolomics was performed to obtain information on the chemical composition of extracts. Ethanol-water-based extraction procedures were the most efficient in isolating polyphenols, while less polar butanol extract contained the highest amount of iridoids. Antioxidant potential analysis revealed stronger activity in extracts with higher polyphenol content. Bacillus cereus and Staphylococus aureus were designated as the most sensitive bacterial strains to the activity of extracts, while among the micromycetes tested, Penicillium funiculosum was the most susceptible strain. Butanol extract showed antivirulence potential on Candida albicans morphological transition from yeast to hyphal form, and selected extracts were effective against biofilm formation in two Candida species. All the extracts tested in this study showed no cytotoxic activity to immortalize human skin keratinocyte cell line (HaCaT), whereas extracts obtained by ethanol-water extraction stand out for their potent wound healing effects. Moreover, the influence of the extraction solvent system on various bioactivities of C. spicatum is reported herein for the first time. Overall, the results presented in this study promote the use of C. spicatum as a source of natural products with potential antioxidant, wound healing, and antimicrobial applications that are potentially safe for human use.

Functional Assay for Measuring Bacterial Degradation of Gemcitabine Chemotherapy.

Drug biotransformation by the host microbiome can impact the therapeutic success of treatment. In the context of cancer, drug degradation can take place within the microenvironment of the targeted tumor by intratumor bacteria. In pancreatic cancer, increased chemo-resistance against the frontline chemotherapy gemcitabine is thought to arise from drug degradation by the tumor microbiome. This bacterial-drug interaction highlights the need for developing rapid assays for monitoring bacterial gemcitabine breakdown. While chemical approaches such as high-performance liquid chromatography are suitable for this task, they require specialized equipment and expertise and are limited in throughput. Functional cell-based assays represent an alternate approach for performing this task. We developed a functional assay to monitor the rate of bacterial gemcitabine breakdown using a highly sensitive bacterial reporter strain. Our method relies on standard laboratory equipment and can be implemented at high throughput to monitor drug breakdown by hundreds of strains simultaneously. This functional assay can be readily adapted to monitor degradation of other drugs. Key features Quantification of gemcitabine breakdown by incubating bacteria that degrades the drug and subsequently testing the growth of a reporter strain on filtered supernatant. Use of an optimized reporter strain that was genetically engineered to be a non-degrader strain and highly sensitive to gemcitabine. A high-throughput assay performed in microplates that can be adjusted for identifying bacteria with a fast or slow gemcitabine degradation rate. The assay results can be compared to results from a standard curve with known drug concentrations to quantify degradation rate.

The Application of Ultrasonic Waves and Microwaves to Improve Antihyperglycaemic and Antimicrobial Activities of Marrubium vulgare Extracts.

Having scarce information about ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) of white horehound (Marrubium vulgare L.), the idea has emerged to determine the optimal process parameters for the maximization of polyphenols and to compare the efficiency of these green extraction technologies. The optimal UAE parameters are temperature of 73.6 °C, extraction time of 40 min and ultrasound power of 30.3 W/L, while the optimal MAE parameters are 63.8% ethanol, extraction time of 15 min and microwave power of 422 W. Extract obtained at optimal UAE parameters shows the highest antihyperglycemic activity (α-amylase inhibition: 50.63% and α-glucosidase inhibition: 48.67%), which can potentially be explained by the presence of chlorogenic acid and quercetin, which were not identified in the macerates. The most sensitive bacterial strain to optimal ultrasonic extract is Bacillus cereus, whereas the most sensitive fungal strain is Saccharomyces cerevisiae.

Isolation and Identification of Flavones Responsible for the Antibacterial Activities of Tillandsia bergeri Extracts.

Plants are an everlasting inspiration source of biologically active compounds. Among these medicinal plants, the biological activity of extracts from some species of the Tillandsia genus has been studied, but the phytochemistry of the hardy species Tillandsia bergeri remains unknown. The aim of the present study was to perform the first phytochemical study of T. bergeri and to identify the compounds responsible for the antibacterial activity of T. bergeri extracts. Soxhlet extraction of predried and grinded leaves was first performed using four increasing polarity solvents. A bio-guided fractionation was performed using agar overlay bioautography as a screening method against 12 Gram-positive, Gram-negative, sensitive, and resistant bacterial strains. The results showed the inhibition of Gram-positive methicillin-sensitive Staphylococcus aureus ATCC 29213 (MSSA), methicillin-resistant S. aureus N-SARM-1 (MRSA), and Staphylococcus caprae ATCC 35538 by the dichloromethane fraction. A phytochemical investigation led to the isolation and identification by high-resolution mass spectrometry and nuclear magnetic resonance of the two flavones penduletin and viscosine, responsible for this antibacterial activity. For viscosine, the minimum inhibitory concentration (MIC) value is equal to 128 μg/mL against MSSA and is equal to 256 μg/mL against MRSA and S. caprae. The combination of these compounds with vancomycin and cloxacillin showed a decrease in MICs of the antibiotics. Penduletin showed synergistic activity when combined with vancomycin against MSSA (FICI < 0.258) and S. caprae (FICI < 0.5). Thus, unexplored Tillandsia species may represent a valuable source for potential antibiotics and adjuvants.

HAZ, a novel peptide with broad-spectrum antibacterial activity

ObjectiveThe growing microbial resistance to antibiotics is a global public concern, which creates serious needs for newer antimicrobial agents. Antimicrobial peptides (AMPs) are increasingly exploited in drug development as therapeutic candidates. Here, we aimed to design and characterize a novel peptide with broad spectrum antimicrobial activity. MethodsHybridization and sequence modification approaches were used to design the novel peptide, named HAZ, aiming at optimizing the physicochemical parameters involved in antimicrobial activity. Peptide activities were assessed alone or combined with different selected antibiotics against various sensitive and drug-resistant bacterial strains. In addition, the hemolysis and the cytotoxic activities of HAZ peptide were evaluated on human red blood cells and epithelial adenocarcinoma cells (A549), respectively. ResultsHAZ peptide was sequentially modified to result in favored physicochemical parameters (helicity 95.24 %, hydrophobic ratio 47 %, and net charge of 8 + ). Functional assessment of HAZ revealed significant antimicrobial activity, with MIC values of 15 – 20 µM against tested bacterial strains. It also exhibited biofilm eradication activity at slightly higher concentrations. HAZ-antibiotics combinations exhibited a synergistic action mode that led to dramatic decrease in the MIC values for both HAZ peptide and the antibiotic. Such efficacy was accompanied with minimal hemolytic toxicity on human erythrocytes. Importantly, HAZ displayed promising anticancer activity against human lung cancer cells. ConclusionRationally-designed antimicrobial peptides offer promising alternatives to the current antibiotics for management of infectious diseases. HAZ peptide is a broad-spectrum AMP, and a promising candidate for antimicrobial and anticancer drug development.

Unraveling the Secrets of Colistin Resistance with Label-Free Raman Spectroscopy.

The rise in number of infections from multidrug-resistant (MDR) Gram-negative microbes has led to an increase in the use of a variety of ‘polymyxins’ such as colistin. Even though colistin is known to cause minor nephro- and neuro-toxicity, it is still considered as last resort antibiotic for treating MDR infections. In this study, we have applied Raman spectroscopy to understand the differences among colistin sensitive and resistant bacterial strains at community level. We have successfully generated colistin resistant clones and verified the presence of resistance-causing MCR-1 plasmid. A unique spectral profile associated with specific drug concentration has been obtained. Successful delineation between resistant and sensitive cells has also been achieved via principal component analysis. Overall findings support the prospective utility of Raman spectroscopy in identifying anti-microbial resistance.

Synthesis, reaction, antimicrobial, and docking study of new chalcones incorporating isoquinoline moiety

Reaction of isoquinoline 1 with hydrazonoyl chlorides 2A–E gave the corresponding triazoloisoquinolines 4A–E. The latter products 4A–E were reacted with 4-(piperidin-1-yl)benzaldehyde 5a and 4-morpholinobenzaldehyde 5b to afford the corresponding chalcones 6a,b. Some of chalcones 6 were reacted with hydrazine hydrate in refluxing ethanol to give the corresponding 8,9-dimethoxy-1-aryl-4,5-dihydro-1H-pyrazol-3-yl-1,5,6,10b-tetrahydro-[1,2,4]triazolo[3,4-a]isoquinoline derivatives 7A–C. Antimicrobial studies were performed using gram-negative bacteria (Escherichia coli) and (Klebsiella pneumonia), a gram-positive bacteria (Streptococcus mutans) and (Staphylococcus aureus), filamentous fungus (Asperagillus Nigar) and yeast (Candida albicans). Data revealed that chalcone 6Aa achieved the lowest MIC values (high efficient derivative) against the sensitive bacterial strain E. coli with MIC value 130 µg/ml. The most effective compound 6Aa, which demonstrated the highest binding affinity toward tested protein [thymidine phosphorylase enzyme, (PDB ID:4EAD)], was docked using MOE 2014.09 software.

Chemical constituents and antibacterial activity of Annickia chlorantha (Oliv.) Setten &amp; Maas (Annonaceae) and their chemophenetic significance

Background: Annickia chlorantha (Annonaceae) is an ornamental tree, which may grow up to 30 m high with dense foliage and spreading crown. It is used in traditional medicine for its anti-infective properties particularly in the treatment of fungal infections, malaria, hepatitis, jaundice and other bacterial infections. This study describes the chemical and antibacterial investigation of ethanol extract of the stem bark of A. chlorantha. Methods: The compounds were obtained by separation using silica gel and Sephadex LH-20 CC. Their structures were elucidated through the analysis of their NMR and MS data. The antibacterial activities of the crude extract and isolated compounds were carried out using microdilution method against five sensitive bacterial strains Results: The chemical investigation of the stem bark of A. chlorantha led to the isolation of ten known secondary metabolites classified into seven alkaloids (1-7), one triterpene (9), and two steroids (8a-8b, 10) including 1,2,3-trimethoxy-4,5-dioxo-6a,-dehydroaporphine A (1), cepharadione B (2), O-methyl-moschatoline (3), palmatine (4), jatrorrhizine (5), columbamine (6), pseudojatrorrhizine (7), the mixture of β-sistosterol (8a) and stigmasterol (8b), cyclofoetigenine A (9) and β-sitosterol-3-O-β-D-glucopyranoside (10). Their structures were elucidated through the analysis of their NMR and MS data. The crude extract exhibited weak antibacterial activity against Staphylococcus aureus (MIC = 1000 µg/mL). Compounds 2 and 4 exhibited moderate activity against Staphylococcus aureus (MIC = 125 µg/mL), while compound 5 displayed the same activity against Shigella flexneri. The chemophenetic significance of the isolated compounds was discussed. Conclusion: The phytochemical and antibacterial investigation carried out on A. chlorantha showed that this plant contains some antibacterial compounds justifying its uses in traditional medicine for the treatment of bacterial infections. Keywords: Annickia chlorantha; Annonaceae; chemophenetic significance; antibacterial activity; phytochemical.

Evaluation of antibacterial activities for three commonly used antibiotics produced by different manufactures on female urinary tract infection Uropathogens in kalar city.

Health professional staff often claims information about trying to differentiate the used antibiotics based on the manufacturers that produce the drug, which may lead to a differentiation in the prescribing of the antibiotics by a physician. Numerous antibiotics produced by different manufactures, under different brands names are available in pharmacies for urinary tract infection (UTI) treatment; this study proceeds to find out and evaluates antibacterial activities of three most used antibiotics, produced by different antibiotic producers on uropathogens in Kalar city. Kirby–Bauer disk diffusion method is employed to assess antibacterial effectiveness of Amikacin (Ak), Levoflaxocilin (Lv) and Nitrofuratoin (Nr) against reference strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus saprophyticus and clinically isolated uropathogens (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus saprophyticus, Proteus vulgaris, and Klebsiella pneumoniae). Inhibition zones (IZ) were determined in millimeter unit to show the activity of the antibiotics. It has been found that the activity of all brands on sensitive bacterial strains were in the preferred range and surpassed the threshold of (IZ) determined by Clinical Laboratories Standards Institute (CLSI) guide. The lack of significant differences among most tested brands for each antibiotic, support this idea.

Antagonistic interactions among marine sedimentary bacteria in multispecies microcosms

AbstractAntagonism among bacteria is widespread and plays an important role in structuring communities. Inhibitory compounds can confer competitive advantage, but energetic trade-offs can result in non-transitive (i.e. ‘rock-paper-scissors’) interactions, ultimately allowing co-existence and community stability. Competition in sedimentary habitats is especially keen given high densities and attachment to inorganic particles. Because measuring trade-offs between bacterial species is challenging, much of our understanding of competitive interactions is based on theoretical modelling and simplified in vitro experiments. Our objectives were to determine (1) if interference competition occurs in microcosms mimicking in situ conditions; (2) whether the presence of sediment influences antagonistic interactions; and (3) if more complex assemblages alleviate or synergize interactions. Four sedimentary isolates, including antibiotic-producing, resistant and susceptible strains were incubated in porewater microcosms in 1-, 2- and 3-species combinations, both with and without natural sediments. Microcosms were sampled over 72 h to generate growth curves using quantitative PCR. Multiple growth attributes (growth rate, maximum density, lag time) were used to assess effects of treatment (species combinations) and environment (sediment vs porewater alone). Antimicrobial producers were more effective at inhibiting target species in microcosms that included sediment, in agreement with theory. We observed growth inhibition by antimicrobial-producing bacteria in both 2- and 3-species microcosms. However, the expected protection of sensitive bacterial strains by resistant strains was observed in only one (of four) 3-species combinations, thus the ‘rock-paper-scissors’ prediction was not fully supported. These results reinforce the notion that interspecies interactions are context-dependent, reliant on environmental conditions and the species involved.