Positive Control Ciprofloxacin Research Articles

Reactivity of (3‐(4‐Fluorophenyl)oxyran‐2‐yl)(naphthalene‐2‐yl)methanone Toward Some Nucleophiles for Preparing Promising Agents with Antimicrobial and Antioxidant Activities

Abstract(3‐(4‐Fluorophenyl)oxyran‐2‐yl)(naphthalene‐2‐yl)methanone 2 was prepared from the reaction of 3‐(4‐fluorophenyl)‐1‐(naphthalen‐2‐yl)prop‐2‐en‐1‐one (1) with hydrogen peroxide and reacted with different nucleophiles such as hydrazine hydrate, phenyl hydrazine, thiosemicarbazide to give 4‐hydroxy‐1H‐pyrazole derivatives 3a,b‐4. Also, compound 2 was treated with hydroxylamine hydrochloride to give the substituted 2,3‐dihydroisoxazole 5. Similarly, compound 2 was treated with carbon disulfide, phenyl isothiocyanate, and phenyl isocyanate to give the corresponding compounds 6–8. Various spectroscopic techniques and elemental analysis were used to determine the molecular structures of the new derivatives. All the new analogs were screened against five human pathogenic microbial strains: Escherichia coli and Pseudomonas aeruginosa as Gram‐negative bacteria, Bacillus subtilis and Staphylococcus aureus as Gram‐positive bacteria and the yeast Candida albicans using agar diffusion method. Compound 4 exhibited moderate antimicrobial activity against all the tested microorganisms compared to positive control ciprofloxacin and fluconazole. On the other hand, the free radical scavenging activity of the new compounds using DPPH assay protocol revealed that most of the compounds have a weak reducing activity. Moreover, compounds 4 and 8 were docked against 1KZN protein (DNA gyrase), 3FYV and 5V5Z showing the ability to interact with key amino acid residues and the potential to act as inhibitors.

Comparative Evaluation of Antimicrobial Activity and Minimum Inhibitory Concentration of Commercially Available Pediatric Dentifrices: An In Vitro Study.

The aim of this study was to evaluate the antimicrobial efficacy and minimum inhibitory concentration (MIC) of commercially available pediatric dentifrices containing different compositions against Streptococcus mutans and Lactobacillus activity. Four different commercially available brands of pediatric dentifrices, designated as sample I-fluoride, sample II-herbal, sample III-xylitol with nanosilver particles, and sample IV-xylitol with fluoride, along with two control groups (a positive control-ciprofloxacin and a negative control-distilled water), were tested for their antibacterial activity by measuring the zone of inhibition, followed by MIC against two dental bacterial pathogens, S. mutans strain and Lactobacillus acidophilus (LB) strain, at five different twofold dilutions of 100, 50, 25%, 12.5, and 6.25% concentrations. All four dentifrices were found to have wide variations in their effectiveness against the two tested microorganisms at 100% (pure) and 50% concentrations, with sample I having the highest activity, followed by sample IV and sample II. At 25% concentration, only sample I and sample IV showed antibacterial activity, while at 12.5 and 6.25% concentrations, none of the tested toothpastes exhibited any antibacterial activity. Sample III failed to show antibacterial activity even in pure form against the two microorganisms. In our present study, the fluoride-containing pediatric dentifrice with a lower fluoride concentration (458 ppm) exhibited the highest zone of inhibition, followed by the xylitol with fluoride dentifrice and the herbal dentifrice. No zone of inhibition was observed in the nanosilver with xylitol dentifrice. Dureha R, Navit S, Khan SA, et al. Comparative Evaluation of Antimicrobial Activity and Minimum Inhibitory Concentration of Commercially Available Pediatric Dentifrices: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(8):938-944.

An in Vitro Approach: Antibacterial Activity of Sansevieria trifasciata Prain. Leaves with Chemometric Analysis

Exploration the antibacterial activity of S.trifasciata Prain. is still limited, therefore this study aims to assess the antibacterial activity of extracts and ethyl acetate fractions of Sansevieria trifasciata Prain. The S.trifasciata leaves was macerated with ethanol 96%, then fractionated using the trituration method with ethyl acetate. The treatment group was divided into positive control group (PC) using ciprofloxacin, negative control (NC) using DMSO, extract, ethyl acetate fraction 5% (ET5%), 10% (ET10%), 20% (ET20%), 40% (ET40 %). Data were analyzed statistically by ANOVA and chemometrically with PCA. The inhibition zone for S.aureus bacteria in each sample is 26.69; 1.40; 23.32;2.82; 6.23; 11.11; 20.15 mm, respectively, E.coli is 26.65;0.63;22.65;3.61;7.11;11.44;21.15 mm respectively, P. aeruginosa is 27.40; 0.00; 23.23; 2.74;7.03;11.69;21.36 mm respectively. Percent inhibition of extract, ET5%, ET10%, ET20%, ET40% on S. aureus bacteria is 82.16; 5.31; 18.12; 36.39; 70.38% respectively, E.coli is 82.67; 11.13; 24.31; 40.56; 76.99% respectively, P. aeruginosa 84.85; 10.01; 25.65; 42.68; 77.98% respectively. Extract and ethyl acetate fraction have significant potential as antibacterial (p<0.05). The results of PCA chemometric analysis showed that the extract and ET40% had similar inhibition zone area to the positive control ciprofloxacin. The extract and the ethyl acetate fraction 40% are promising for development as antibacterials. Keywords: Sansevieria trifasciata Prain., chemometric, bacterial

Antibacterial p-terphenyl and α‑pyrone derivates isolated from the marine-derived actinomycete Nocardiopsis sp. HDN154086.

Assisted by OSMAC strategy, one new p-terphenyl and two new α‑pyrone derivates, namely nocarterphenyl I (1) and nocardiopyrone D-E (2-3), were obtained and characterized from the marine sediment-derived actinomycete Nocardiopsis sp. HDN154086. The structures of these compounds were determined on the basis of MS, NMR spectroscopic data and single-crystal X-ray diffraction. Compound 1 with a rare 2,2'-bithiazole structure among natural products showed promising activity against five bacteria with MIC values ranging from 0.8 to 1.6 μM and 3 exhibited notable antibacterial activity against MRSA compared the positive control ciprofloxacin.

UJI AKTIVITAS ANTIBAKTERI EKSTRAK ETANOL DAUN BENALU BATU (Begonia sp) TERHADAP BAKTERI Staphylococcus aureus DAN Escherichia coli

Empirically, begonia leaves are used as a treatment for cancer and ulcers. contains chemical compounds of flavonoids, alkaloids, saponins, tannins and steroids. This study aims to determine the antibacterial activity of ethanol extract of begonia and its effective concentration against Escherichia coli and Staphylococcus aureus bacteria. Extraction with 96% ethanol extract using the maceration method. Phytochemical screening test, antibacterial test using various concentrations of 30%, 50%, 100%, positive control (ciprofloxacin) and negative control (aquadest steril) using the disk diffusion method. The results of the phytochemical screening of begonia extract contain alkaloids, flavonoids and tannins. The results of the antibacterial activity test for Staphylococcus aureus were obtained with an inhibitory zone concentration of 30%, namely 3.75 mm, 50%, namely 4.37 mm, and 100%, namely 4.87 mm. Meanwhile, Escherichia coli bacteria obtained a concentration of 30%, namely 4.37mm, 50%, namely 4.62 mm, and 100% is nm 4.75mm. The diameter of the inhibition zone for the positive control of ciprofloxacin against Staphylococcus aureus bacteria was 40.31mm and Escherichia coli was 44.12mm. The ethanol extract of begonia leaves can inhibit the growth of Staphylococcus aureus bacteria at a concentration of 100% is 4.87mm and Escherichia coli bacteria at a concentration of 100% is 4.75mm

Aktivitas Antibakteri Kombinasi Ekstrak Biji Manjakani (Quercus infectoria) Dan Daun Sirih Merah (Piper crocatum) Terhadap Pertumbuhan Bakteri Klebsiella pneumoniae

Potential plants found in Indonesia that can be used for the treatment of urinary tract infections include: Manjakani seeds (Quercus infectoria) and red betel leaves (Piper crocatum). Manjakani seeds are pharmacologically claimed to have biological activities such as anti-inflammatory, antibacterial and antifungal. Red betel leaf has the potential as an antibacterial in the treatment of infectious diseases. The purpose of this study was to determine the antibacterial activity of the combination of manjakani seed extract and red betel leaf in inhibiting the growth of Klebsiella pneumoniae bacteria. The type of research used istrue experiment study with a completely randomized design (CRD) with three factors, namely the type of solvent n-hexane, ethyl acetate, ethanol 96%, ratio (1:1,1:2,2:1) and concentration (75%,100%) with each treatment being repeated twice. This research was conducted in the microbiology laboratory, Labkes, East Kalimantan. The population in this study is the manjakani plant and red betel plant and tested using the agar diffusion technique method Kirby Bauer with positive control (Ciprofloxacin) and negative control (aquadest). Data analysis used is One Way ANOVA and advanced test methods Duncan with a significance level of 0,05. The results obtained showed that there was an effect of antibacterial activity of Manjakani seed extract and red betel leaf on growth K. pneumoniae. The most effective concentration was found in ethanol 96% extract, (2:1 combination of 100% concentration) of 13,97 mm and an effectiveness of 55,74% with a positive control ciprofloxacin 5µg of 25,06 mm. It can be concluded that the combined extract of manjakani seeds and red betel leaves has antibacterial activity against bacteria Klebsiella pneumoniae,but the potential is still low of ciprofloxacin.

Phytochemical Screening And Activity Test of Maja Fruit Extract (Aegle Marmelos L.) on Growth Salmonella typhi and Vibrio cholerae

Maja fruit (Aegle marmelos L.) contains secondary metabolites that have antibacterial activity in the form of steroids, flavonoids and saponins, which are not used optimally. The target of this study was to observe the antibacterial activity of Maja fruit (Aegle armelos L.) extract on Vibrio cholera and Salmonella typhi. The extraction method formed by maceration and using 96% ethanol solution then the antibacterial activity was tested on the agar diffusion technique. The results of the study show that the range of inhibition zone diameter (mm) is gradual for the Maja Fruit (Aegle marmelos L.) extract test at concentrations of 2%, 4%, 8%. For Salmonella typhi was 13 mm;16,3 mm;19 mm but ciprofloxacin as a positive control was 57mm and DMSO as a negative control did not show any inhibition zone. However, the diameter of the inhibition zone in Vibrio cholera was found to be in the range of 13 mm;18.3 mm;19.6 mm and the positive control ciprofloxacin was 32.3 mm , but the negative control did not have an inhibiting zone. The results of statistical tests showed that Maja fruit (Aegle marmelos L.) extract had antibacterial activity on Vibrio cholerae and Salmonella typhi at the maximum concentration of 2% w/v (P <0.05).

Antibacterial Activity of Pineapple Peel Eco-enzyme (Ananas comosus L.) on Growth Pseudomonas aeruginosa and Staphylococcus epidermidis

Eco-enzyme is a fermented product from an organic waste substrate, molasses, and water. Eco-enzyme can be used as antibacterial because it produces organic compounds such as alcohol and acetic acid. Pineapple peel waste (Ananas comosus L.) can be used as an eco-enzyme. This study aimed to test the antibacterial activity of pineapple peel eco enzyme against Pseudomonas aeruginosa and Staphylococcus epidermidis. The study used the method of determining the Minimum Inhibitory Concentration (MIC) and Minimum Killing Concentration (MBC) of pineapple peel eco-enzyme with 8 treatment levels namely negative control (aquadest), positive control (ciprofloxacin 5 mg/mL), 3.125%, 6.25 %, 12.5%, 25%, 50%, and 100% eco-enzymes. Based on the research results, it was known that the MIC value of pineapple peel eco-enzyme against P. aeruginosa, and S. epidermidis was 12.5% and 3.125%, respectively. Eco- enzymes from pineapple peel did not show minimum killing concentrations. Eco-enzyme of pineapple peel is only bacteriostatic towards the growth of P. aeruginosa and S. epidermidis bacteria.

Novel indole derivatives of dihydropyrimidinone: Synthesis, characterization, molecular docking and antimicrobial activity

The enaminone was reacted with substituted aldehyde and urea in glacial acetic acid. The indole derivatives of dihydropyrimidinone were obtained in good yield. Spectroscopic methods were employed to confirm and characterize the structures of all novel synthesized compounds. All the compounds were screened for antimicrobial activity against Gram-positive, Gram-negative, and Candida albicans. Most of the synthesized compounds were active against all tested trains. Enaminone was found to be highly active against all strains except P. aeruginosa and S. typhi. Enaminone presented (MIC = 64 µg/mL) against S. pneumonia, (MIC = 16 µg/mL) against B. anthracis, and (MIC = 32 µg/mL) against S. aureus as compared to positive control erythromycin (MIC = 8 µg/mL), gentamycin (MIC = 2 µg/mL) and ciprofloxacin (MIC = 4 g/L) respectively. A molecular docking study was performed at the active site of E. coli DNA gyrase, K. pneumonia DNA gyrase, and topoisomerase IV. The results showed that the compound with phenyl substitution exhibited an inhibition zone of 18 mm against E. coli and presented the highest binding energy S = -9.83 kcal/mol. It showed three π−bonds with (DA20, and DT15), aromatic rings in the molecule, and the carboxyl groups of the urea ring chelated Mg2+. Compound with 4-nitrophenyl exhibited an inhibition zone of 13.6 mm against K. pneumoniae. It also presented the highest binding energy S = -9.55 kcal/mol. LYS444 and DC315 were predicted to form an H-bond donor with hydrogen in phenyl and urea rings. All the compounds followed Lipinski's rule of five without any violation.

POTENSI ANTIBAKTERI EKSTRAK ETANOL DAUN SELUTUI PUKA (Tabernaemontana macrocarpa Jack.) TERHADAP BAKTERI Streptococcus mutans DAN Porphyromonas gingivalis

The Dayak people in West Kutai, East Kalimantan use selutui puka leaves for the treatment of toothache and canker sores. Bacteria that often cause infections in the oral cavity are Streptococcus mutans and Porphyromonas gingivalis. The aim of this study was to determine the activity of the ethanol extract of selutui puka leaves as an antibacterial against Streptococcus mutans and Porphyromonas gingivalis. The research phase involved collecting samples, plant determination, preparing simplicia, preparing extracts and testing antibacterial activity using the paper disc diffusion method with extract concentrations of 15%, 30% and 45%, DMSO negative control 1%, positive control Ciprofloxacin 0.1%. The results showed that the average diameter of the inhibition zone for Streptococcus mutans at an extract concentration of 15% was 17.70 mm (strong), 30% was 19.43 mm (strong), and 45% was 23.60 mm (very strong). ) and against Porphyromonas gingivalis bacteria at an extract concentration of 15% of 17.43 mm (strong), 30% of 23.33 mm (very strong), and 45% of 26.03 mm (very strong).

Effectiveness of Wresah (Amomum Dealbatum) Extract in Inhibiting the Growth of Staphylococcus Aureus

Wresah plant (Amomum dealbatum) is one of the typical fruit species from Lombok Island which has a distinctive fragrance and is a member of the ginger-ginger tribe. This study aims to test the ethanol extract of Wresah skin (Amomum dealbatum) as an antibacterial (Staphylococcus aureus) with concentrations of 15%, 30% and 50%. The research method conducted was laboratory experimental. The antibacterial test of Staphyloccocus aureus was carried out with five treatment groups and five repetitions, namely positive control (ciprofloxacin), negative control (distilled water), concentrations of 15%, 30% and 50% using well method and then incubated for 24 hours at a temperature of 370 C. The results of the antibacterial test of ethanol extract of Wresah fruit peel showed inhibition of Staphylococcus aureus bacteria and at concentrations of 15%, 30%, and 50% which produced the largest diameter of the inhibition zone with an average diameter of 2.0 mm. The Kruskal Wallis test showed a statistically significant difference between the three concentrations tested (p < 0.05), which means that Wresah fruit peel extract is able to inhibit the growth of Staphylococcus aureus bacteria. In conclusion, the extract of Wresah fruit peel has demonstrated antibacterial properties against Staphylococcus aureus and can be used as a natural alternative to conventional antibiotics.

Antibacterial Activity of Ethanolic Leaves Extract of the Plant Andographis Paniculata on Clinical Isolates of Staphylococcus aureus and Escherichia coli

The search for compounds with antimicrobial activity has gained increasing importance in recent times, due to growing worldwide concern about the alarming increase in rate of infection by antibiotic-resistant microorganisms. Antibacterial activity of the ethanolic leaf extracts of Andographis paniculata against Staphylococcus aureus and Escherichia coli was studied. The fresh leaves of Andographis paniculata were collected randomly from a local farm in Alulu Enugu East L.G.A Enugu State Nigeria. The leaf samples were morphologically identified, washed, air dried at room temperature and milled into powder. Thirty-nine grams of the powder total weight of the extract, was macerated using ethanol as solvent. Phytochemical analysis of the leaves extract was carried out and the results showed that Saponins (++), Tannins (++), Flavonoids (+++), Phenols (+++), Steroids (++) were present while Terpenoids (-), Alkaloids (-) and Glycosides (-) were absent. The extract was concentrated by evaporation at various concentrations (100mg/ml, 300mg/ml, and 500mg/ml) prepared using 5% DMSO. Antibacterial activity was determined using agar well diffusion method, and results showed that there was no antibacterial activity of ethanolic leaf extracts of A. paniculata against E. coli while there was inhibition zones of 20 mm, 17 mm and15 mm against Staphylococcus aureus respectively. The Minimum inhibitory concentration was determined and the results showed that at 12.5mg/ml concentration, the extract was able to inhibit the growth of Staphylococcus aureus. The Minimum inhibitory concentration was determined and the results showed that at 12.5mg/ml concentration, the extract was able to inhibit the growth of Staphylococcus aureus. This study therefore showed that ethanolic extracts of Andographis paniculata has activity against the Staphylococcus aureus since they exhibited comparable activity with the positive control ciprofloxacin.

Antibacterial Activity of Ethanolic Leaves Extract of Andographis paniculata on Isolates of Salmonella spp. and Escherichia coli from Locally Processed Beverages in Umueze Nkanu West Local Government Area Enugu State Nigeria

The microbial contamination of locally processed beverages has been familiar among microbiological researchers who have repeatedly implicated them as the major cause of endemics due to poor processing. However, due to antimicrobial resistance and the need to discover new antimicrobial plants, Antibacterial activity of ethanolic leaf extracts of Andographis paniculata against isolates of Salmonella spp. and Esherichia coli from zobo and soya milk was studied. Andographis paniculata leaves were collected randomly from a local farm in Emene Enugu East L.G.A Enugu State. The leaves samples were identified morphologically, washed, air dried at room temperature and milled into powder. 39.7 g of the powder was macerated with ethanol during the extraction process. Phytochemical analysis was carried out on the extract and result showed that Saponins, Tanins, Flavanoids, Phenols, Steriods were present with Flavanoids and Saponins being in higher concentration, while Terpernoids, Alkaloids and Glycosides were absent. The zobo and soya milk samples were diluted using 10-fold serial dilution method and introduced into the already prepared MacConkey and Salmonella Shigella Agar for incubation. Isolates from zobo and soya milk were characterized, biochemically and morphologically and were identified as E. coli and Salmonella spp. Antibacterial activity of ethanolic leaf extracts of A. paniculata against E. coli and Salmonella spp. was determined using agar well diffusion method, and result showed that there was no antibacterial activity of ethanolic leaf extracts of A. paniculata against E. coli and Salmonella spp. However, absence of Terpernoids, Alkaloids and Glycosides exhibited non-comparable activity with the positive control (ciprofloxacin).

Efficacy of delafloxacin against the biothreat pathogen Bacillus anthracis.

To evaluate the in vitro activity and in vivo efficacy of delafloxacin against Bacillus anthracis, the causative agent of anthrax. MICs were obtained according to CLSI guidelines for 30 virulent isolates and 14 attenuated antibiotic-resistant strains. For the in vivo efficacy study, mice were administered delafloxacin (30-62.5 mg/kg) subcutaneously, or ciprofloxacin (30 mg/kg) intraperitoneally beginning at either 24 or 48 ± 1 h post-challenge (post-exposure prophylaxis) and continued every 12 h for 14 days with study termination on day 30. The mean inhaled dose in the study was approximately 103 × LD50 equivalents, and the range was 87-120 × LD50. Delafloxacin (MIC90 = 0.004 mg/L) was 16-fold more potent than ciprofloxacin (MIC90 = 0.06 mg/L) against a 30-strain set of virulent B. anthracis. Against a panel of attenuated antibiotic-resistant strains, delafloxacin demonstrated potency ≥128-fold over that observed with ciprofloxacin. When evaluated in vivo, mice treated with all delafloxacin doses tested at 24 h post-challenge demonstrated equivalent survival compared with mice treated with the positive control ciprofloxacin. Because of the high challenge dose of spores, mice treated at 48 h showed rapid and high mortality in all groups including the positive control. Surviving animals in all delafloxacin- and ciprofloxacin-treated groups (24 and 48 h) showed complete splenic clearance of infection and <2.2 × 103 cfu/g lung tissue. Given the high bar set by the 100 × LD50 challenge dose in this study, the results from delafloxacin treatment are promising for the treatment of inhaled anthrax.

Antibiofilm Potential of Pisang Batu Extract (Musa balbisiana Colla) for Staphylococcus aureus Bacteria

Phytochemical compounds present in Pisang Batu (Musa balbisiana Colla) can inhibit the growth of bacteria on the surface of a film. This study aims to determine the effect of the anti-biofilm capacity of Pisang Batu extract ( Musa balbisiana Colla) on Staphylococcus aureus bacteria and to determine significant differences in the antibiofilm capacity of Pisang Batu extract (Musa balbisiana Colla) against Staphylococcus aureus bacteria. This study used an experimental method consisting of 6 treatments with 4 replications. The treatment group was a concentration of 25%, 50%, 75%, 100%, positive control (Ciprofloxacin ), and negative control (CMC 1%). Measurement of biofilm inhibition was obtained from the reading of the Optical Density Value on the tool spectrophotometer which then calculated the percentage inhibition biofilm. Data were analyzed using the One Way Anova Test and then Duncan’s Post Hoc test was carried out. The results showed that Pisang Batu extract had an effect on the antibiofilm effect of Pisang Batu extract (Musa balbisiana Colla) on Staphylococcus aureus bacteria where at a concentration of 100% an inhibition percentage value of 39.8% was obtained, a concentration of 75% obtained an inhibition percentage value of 58.03%, 50% concentration obtained inhibition percentage value of 28.11%, 25% concentration obtained inhibition percentage value of 18.06%, control positive (Ciprofloxacin ) obtained an inhibition percentage value of 95.19% and negative control (CMC 1%) obtained an inhibition percentage value of 0%. Then after further testing, a significant difference was obtained for all treatment groups with the best concentration obtained at a concentration of 75%.

Effectiveness of Jambi Forest Honey and Klanceng Honey in Inhibiting Escherichia coli and Klebsiella pneumonia ESBL

Bacterial resistance to antibiotics is a global problem that occurs around the world, both in hospitals and in communities. Antibiotic resistance can affect therapeutic outcomes, therapeutic costs, the spread of disease, and length of illness. The purpose of this study is to find out the potential of Jambi forest honey and Klanceng Honey in inhibiting the growth of ESBL-producing Escherichia coli and Klebsiella pneumonia. This study used experimental laboratory using posttest with control approach, conducted at the STIKES Nasional Bacteriology laboratory. The results showed that Jambi forest honey and Klanceng honey had better potential to inhibit the growth of ESBL-producing Escherichia coli and Klebsiella pneumonia than cefotaxime and ceftriaxone, but less than ceftazidime. On the other hand, honey samples had weaker inhibition potential against positive control (ciprofloxacin for K pneumoniae and chloramphenicol for E coli).

Antibacterial activity test of ethanol extract of rambusa leaves (Passiflora foetida L.) against Pseudomonas aeruginosa bacteria

One of the medicinal plants in Indonesia is rambutan (Passiflora foetida L.). Some of the chemical substances contained in the leaves of rambusa include alkaloids, flavonoids, steroids, and triterpenoids which have an antibacterial effect. This study aims to determine the activity and concentration of effective antibacterial from the extract of rambutan leaves on the growth of Pseudomonas aeruginosa bacteria. The antibacterial test was carried out using disc diffusion or the Kirby method with test concentrations of 10%, 15%, 20%, and positive control (Ciprofloxacin). The results showed that the antibacterial inhibition of rambutan leaf extract concentrations of 10%, 15%, 20%, and positive control was 2.63 mm, 4.53 mm, 6.05 mm, and 26.72 respectively. The concentration of 20% of rambusa leaf extract showed moderate antibacterial activity with an inhibition zone diameter of 6.05 mm.

Synergistic antibacterial effect of ethanolic extract of Carica papaya and Psidium guajava leave extract on Salmonella typhi, Escherichia coli and Klebsiella pneumoniae

This study assessed the synergistic antibacterial effect of ethanol extract of Carica papaya and Psidium guajava on Salmonella typhi, Escherichia coli and Klebsiella pneumoniae using agar well diffusion method and microdilution with Microtitre plates. Qualitative phytochemical analysis of the extract reveals the presence of alkaloids, saponins, glycosides, steroids, soluble carbohydrates and phenols. Five (5) grams of the freeze-dried extract was dissolved in 10ml of 10% Dimethyl Sulphoxide (DMSO) and used for sensitivity against selected standard isolates. Upon sensitivity testing, this study observes a significant inhibition zone diameter at the highest concentration of the extract (500 mg/ml) against Klebsiella pneumoniae with an inhibition zone diameter of 31.0mm relative to the inhibition zone diameters of Escherichia coli and Salmonella typhi with (19.5 mm) and (20.5 mm) respectively. The inhibition zone diameters of the positive control (ciprofloxacin solution) at 500 mg/mL for Klebsiella pneumoniae, Escherichia coli and Salmonella typhi was 36.0 mm, 37.5 mm and 34.5 mm respectively. Escherichia coli has minimal inhibitory concentration (MIC) of 0.977 mg/ml while Klebsiella pneumoniae and Salmonella typhi have their minimal inhibitory concentration (MIC) at 31.25 mg/ml and 62.5 mg/ml respectively.

Molecular Characterization of Bacterial Isolates from Soil Samples and Evaluation of their Antibacterial Potential against MDRS

Some soil microbes, with their diverse inhabitance, biologically active metabolites, and endospore formation, gave them characteristic predominance and recognition among other microbial communities. The present study collected ten soil samples from green land, agricultural and marshy soil sites of Khyber Pakhtunkhwa, Pakistan. After culturing on described media, the bacterial isolates were identified through phenotypic, biochemical and phylogenetic analysis. Our phylogenetic analysis revealed three bacterial isolates, A6S7, A1S6, and A1S10, showing 99% nucleotides sequence similarity with Brevibacillus formosus, Bacillus Subtilis and Paenibacillus dendritiformis. The crude extract was prepared from bacterial isolates to assess the anti-bacterial potential against various targeted multidrug-resistant strains (MDRS), including Acinetobacter baumannii (ATCC 19606), Methicillin-resistant Staphylococcus aureus (MRSA) (BAA-1683), Klebsiella pneumoniae (ATCC 13883), Pseudomonas aeruginosa (BAA-2108), Staphylococcus aureus (ATCC 292013), Escherichia coli (ATCC25922) and Salmonella typhi (ATCC 14028). Our analysis revealed that all bacterial extracts possess activity against Gram-negative and Gram-positive bacteria at a concentration of 5 mg/mL, efficiently restricting the growth of E. coli compared with positive control ciprofloxacin. The study concluded that the identified species have the potential to produce antimicrobial compounds which can be used to control different microbial infections, especially MDRS. Moreover, the analysis of the bacterial extracts through GC-MS indicated the presence of different antimicrobial compounds such as propanoic acid, oxalic acid, phenol and hexadecanoic acid.

Antibacterial angucyclinone and α-pyrone derivatives from desert-derived Nocardiopsis dassonvillei HDN 154151.

One new angucyclinone derivative, Kanglemycin N (1), and two new biogenetically related α-Pyrones, nocapyrones U-V (2-3), were isolated from a desert-derived Actinomycete Nocardiopsis dassonvillei HDN 154151. Their structures, including absolute configurations, were elucidated by extensive NMR, MS, and ECD analyses. Compound 1 exhibited potent antibacterial activity against Bacillus subtilis, Proteus sp., Vibrio Parahaemolyticus, Escherichia coli and Methicillin-resistant Staphylococcus aureus (MRSA) with MIC values ranging from 0.39 μM to 1.56 μM, and notably the effect of 1 against MRSA significantly exceeded the positive control ciprofloxacin. In addition, compound 1 also showed moderate cytotoxic activity against H69AR, MDA-MB-231, ASPC-1 and K562 cell lines, with IC50 values of 10.46, 8.78, 9.28 and 8.61 μM, respectively.