Agar Disc Diffusion Research Articles

Isolation and Identification of Flavonoid Compounds and Antibacterial Activity Test of the Canyere Badak Plant (Bridelia glauca Blume) (Phyllanthaceae)

Flavonoid compounds from the stem bark of the Canyere Badak plant (Bridelia glauca Blume) have been isolated. 2500 g of Canyere Badak plant stem bark was macerated by methanol, and the methanol extract dissolved in distilled water. The distilled water solution was extracted by partitioning with ethyl acetate repeatedly until negative to 5% FeCl3. The ethyl acetate extract was dissolved in methanol and extracted by partitioning with n-hexane until the n-hexane layer was transparent. The methanol extract was analyzed by thin layer chromatography and separated by column chromatography with a stationary phase of silica gel and a mobile phase of chloroform: methanol (90:10; 80:20; 70:30; 60:40) v/v. Fractions 148-174 were purified by preparative thin layer chromatography using benzene: acetone (80:20) v/v eluent to produce a brownish yellow paste of 10 mg at Rf value of 0,66 using chloroform: methanol (80:20) v/v as eluent. Based on the analysis of the UV-visible spectrophotometer, it had a wavelength (λ max) of 275 nm. The FT-IR spectrum shows the presence of OH, C=C aromatic, C=O ketones, C-H, C-O-C and C-O groups. The proton Nucleus Magnetic Resonance Spectrum (1H-NMR) indicates the presence of H-2’ & H-6’ protons, H-3’ & H-5’ protons and methoxy protons. Based on the data analysis and interpretation, the isolated compound was a flavonoid of the flavanones group. The antibacterial activity of total flavonoids was determined by agar disk diffusion against Staphylococcus aureus and Escherichia coli bacteria. The results showed that total flavonoids strongly inhibited the growth of Staphylococcus aureus and Escherichia coli bacteria with MIC (Minimum Inhibitory Concentration) value at a concentration of 100 mg/mL obtained a clear zone of 9.5 mm against Staphylococcus aureus bacteria and at a concentration of 100 mg/mL obtained a clear zone of 12.15 mm against Escherichia coli bacteria.

Green synthesis of ZnO nanoparticles using peels of Citrus limetta and evaluation of their antibacterial activity

Background: The fruit peel wastes produced during the processing of different agriculture-related products after production are not utilized to their full potential, and their environmental impact has become a significant global issue. Citrus peel waste is rich in nutrients and has biopotential activity. Objective: The main objective of the current study is to analyze peels of Citrus limetta qualitatively and quantitatively and synthesize Zinc oxide Nanoparticles using the green synthesis method. Methodology: The synthesized ZnO NPs were characterized by UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and Scanning electron microscopy (SEM). The antibacterial activity of C. limetta peels ZnO NPs against Pseudomonas aeruginosa was evaluated by the Agar Disc Diffusion method. Results: The UV-Vis spectrum was measured in the 200 – 400 nm range, and the crystalline structure was analyzed via XRD. SEM/EDS analysis confirmed the nano-spherical structures and the agglomeration of the synthesized ZnO NPs. A minimal inhibitory effect against the Pseudomonas aeruginosa by C. limetta peels ZnO NPs was observed. Conclusion: Hence, the green synthesized ZnO NPs offer an effective and economical way to utilize citrus peel waste in both food and non-food sectors.

Novel Synthesis and Characterization of Some Chlorosubstituted Aryl Substituted 1,3-thiazole as Antibacterial Agents

The synthesis, spectral analysis and biological activities of 5-(2’-hydroxy-3’,5’-dichlorophenyl)-4-heptan-1-one- 2-[4-(2-hydroxy-3,5-dichlorophenyl)-2-mercapto-imidazolo]-1,3-thiazole (8d2) (J”) have been carried out. In this case 5-(2’-hydroxy-3’,5’-dichlorophenyl)-4-(heptan-1-one)-2- amino-1,3-thiazole (8d) (J), 5-(2’-hydroxy-3’,5’-dichlorophenyl)-4-heptan-1-one-2-[(2-hydroxy-3,5-dichlorophenyl) ethanonylamino]-1,3-thiazole (8d1) (J’) & 5-(2’-hydroxy-3’,5’-dichlorophenyl)-4-heptan-1-one- 2-[4-(2-hydroxy-3,5-dichlorophenyl)-2-mercapto-imidazolo]-1,3-thiazole (8d2) (J”) have been screened. The compound (J) was synthesized from 1-(2’-Hydroxy-3’,5’-dichlorophenyl)-2-bromo-1,3-nonanedione (a4) by the action of thiourea, while (J”) was synthesized from (J) by reaction with α-bromo, 2-hydroxy-3,5 dichloroacetophenone to get 5-(2’-hydroxy-3’,5’-dichlorophenyl)-4-heptan-1-one-2-[(2-hydroxy-3,5-dichlorophenyl)ethanonylamino]-1,3-thiazole (8d1) (J’). Further (J’) on treatment with KSCN was dissolved in acetic acid gave (J’’). The nanoparticles of the compounds J, J’and J’’ have been prepared by using ultrasonic technique. The newly synthesized titled compound and it’s nanoparticles were screened for their antibacterial activity against some pathogens ; Gram+ve bacteria viz. Staphylococcus pneumoniae, Staphylococcus aureus and Gram-ve bacteria viz. Escherichia coli and Pseudomonas fluorescens by using agar disc diffusion method.All the newly synthesized compounds were found to be active against test pathogens.

Antimicrobial resistance profiles of salmonella spp. and escherichia coli isolated from fresh nile tilapia (oreochromis niloticus) fish marketed for human consumption

BackgroundSalmonella spp. and pathogenic strains of Escherichia coli are among the major foodborne zoonotic pathogens. These bacterial pathogens cause human illnesses characterized by hemorrhagic colitis, vomiting, nausea, and other agent-related symptoms. The increasing occurrence of antimicrobial resistance in these pathogens is also a serious public health concern globally. Regular surveillance of phenotypes and genotypes of Salmonella spp. and Escherichia coli from animal-derived foods is necessary for effective reduction and control of these foodborne pathogens. This study was conducted to assess the occurrence, antimicrobial resistance, virulence genes and genetic diversity of Salmonella spp. and E. coli isolates from fresh Nile tilapia obtained from retail markets in Nairobi, Kenya.MethodsA total of 68 fresh Nile tilapia fish samples were collected from retail markets and used for isolation of Salmonella spp. and E. coli. Antimicrobial susceptibilities of the isolates weretested by Kirby-Bauer agar disc diffusion method. According to the antimicrobial resistance profiles, the multi-drug resistant isolates were identified by 16 S rRNA sequencing and phylogenetic analysis using the Bayesian inference method. The MDR Salmonella spp. and E. coli isolates were subjected to PCR-based screening for the detection virulence and antibiotic resistance genes.ResultsThe prevalence of contamination of the fish samples with Salmonella spp. and E.coli was 26.47% and 35.29% respectively. Overall phenotypic resistance among the Salmonella spp. ranged from 5.5% for ceftazidime, chloramphenicol, meropenem, nitrofurantoin and streptomycin and 22.2% for penicillin-G. For E. coli phenotypic resistance ranged from 4.2% for ceftazidime and chloramphenicol and 25% for rifampicin. Multi-drug resistance was observed in three Salmonella spp. and two E. coli isolates. Results of 16 S rRNA sequences, sequence alignment and phylogenic trees confirmed the identified MDR isolates as S. typhymurium WES-09, S. typhymurium MAK-22, S. typhimurium EMB-32 and E. coli MAK-26 and E. coli LAN-35. The presence of antibiotic-resistance genes belonging to β-lactamases, tetracycline, sulfonamide, trimethoprim and aminoglycosides-resistant genes were detected in all the identified MDR isolates.ConclusionsThe findings from this study indicate that Nile tilapia (Oreochromis niloticus) sold in retail markets can acts as reservoirs of Salmonella spp. and E. coli pathogens linked to human disease, some of which were multidrug resistance to critically important antimicrobials. Both microorganisms are of zoonotic significance and represent a significant public health risk to the society.

Green Synthesis of Zinc Oxide Nanoparticles Using Ananas comosus Extract: Preparation, Characterization, and Antimicrobial Efficacy.

Background This study aimed to environmentally synthesize zinc oxide nanoparticles (ZnO-NPs) using Ananas comosus (AC) extract and evaluated their antimicrobial efficacy against Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis. Methodology AC extract was combined with a zinc sulfate solution to synthesize ZnO-NPs. The NPs were characterized using UV-visible spectroscopy, Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), and energy-dispersive electron microscopy (EDX). Antimicrobial activity was assessed using the agar disc diffusion method against S. aureus, S. mutans, and E. faecalis. Results Green synthesis of ZnO-NPs with AC extract yielded NPs of different sizes and shapes. SEM analysis showed circular and conical NPs measuring up to 10 nm. EDX analysis confirmed the presence of zinc (Zn) and oxygen (O) particles. UV-visible spectroscopy indicated ZnO-NP formation with a peak at 290 nm. These NPs exhibited strong antimicrobial activity against S. aureus, with larger inhibition zones at higher concentrations, i.e., 15 mm at 100 μL. Whereas they showed low activity of 12 mm at 100 μL against S. mutansand showed no activity against E. faecalis. Conclusions Environmentally friendly synthesis of ZnO-NPs using AC extract provides an effective method for NP production. It exhibits strong antimicrobial activity against S. aureus, indicating the potential for targeted antimicrobial solutions in addressing associated infections.

Environmentally friendly production, characterization, and evaluation of ZnO NPs from Bixa orellana leaf extract and assessment of its antimicrobial activity

Zinc oxide nanoparticles (ZnO NPs) are establishing themselves as an important class of nanomaterials due to their exceptional physicochemical properties and wide range of applications. Due to their affordability, lack of toxicity, and strong biocompatibility, ZnO NPs find extensive use in the field of biomedicine. ZnO NPs are promising in biomedicine, especially for their ability as anticancer and antimicrobial agents. The ecologically sustainable preparation of metallic NPs using different plant extracts is a viable alternative to more conventional synthesis methods. The present study investigates the effects of changing the physical conditions on ZnO NPs synthesis from Bixa orellana (B. orellana) extract using the precipitation method. Confirmation and characterization of the ZnO NPs were achieved by analytical techniques. EDS results verified that highly pure ZnO NPs were synthesized. X-ray diffraction analysis verified the crystal nature of the synthesized NPs and their crystalline particle size of 82.66 nm. The XRD graphs strongly indicate the formation of wurtzite ZnO due to the presence of the (100), (002), and (101) planes. The antibacterial activity was assessed through the utilization of agar disc diffusion. The findings revealed that ZnO NPs exhibited significant efficacy in inhibiting the growth of both Gram-positive and Gram-negative bacteria. The zone of inhibition with the greatest diameter (22 mm) was reported for the bacterial strain B. cereus. The present investigation provides evidence that B. orellana leaves extract is capable of producing ZnO NPs, which play a crucial role in its antibacterial action. Additional investigation is necessary to validate the role of diverse phytochemicals in the synthesis of ZnO NPs and their applications in diverse fields such as agriculture, cosmetics, food, and healthcare.

Exploring the wound-healing and antimicrobial potential of Dittrichia viscosa L lipidic extract: Chemical composition and in vivo evaluation

Dittrichia viscosa belongs to the Dittrichia genus, it grows abundantly in the east and northeast of Morocco, and traditionally its fresh leaves are crushed and given for topical application after burns, wounds, and infections. In this study, we examine the wound-healing activity of Dittrichia viscosa lipidic extract in vivo, assess its anti-microbial effect, and explore the specific compounds that contribute to these effects. To assess the effectiveness of wound healing, a burn-induced wound model was employed in Wistar rats, and the levels of hydroxyproline as well as histopathological changes in the skin tissues were evaluated. Furthermore, the antimicrobial potential against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Candida glabrata, and Malassezia furfur was investigated using the agar disc diffusion method. Gas Chromatography-mass spectrometry (GC–MS) and high-performance liquid chromatography (HPLC) techniques were employed to analyze the composition of fatty acids, phytosterols, and tocopherols. Topical application of Dittrichia viscosa lipidic fraction ointment exhibited significant improvements in wound contraction, achieving an impressive rate of 82% within 21 days. Additionally, the lipidic extract of Dittrichia viscosa displayed notable efficacy against various microbial strains, including Candida albicans (25.07 ± 0.2), Candida glabrata (24 ± 0.6), and Malassezia furfur (22 ± 0.7). The primary fatty acids identified in the sample were linolenic acid (58.95% ± 0), oleic acid (16.75% ±0.04), and linoleic acid (11.97% ± 0.1). Notably, the sample contained significant amounts of γ-Tocopherols (732.08 ± 21mg/kg), while the sterol fraction primarily consisted of 7-Campesterol (1937 ± 0 mg/kg), 7-β-Sitosterol (1621 ± 0 mg/kg), and Stigmasterol (1439 ± 26 mg/kg). By its richness in active compound content, Dittrichia viscosa effectively accelerates wound healing while safeguarding against microbial infections.

Dietary Administration Effects of Exopolysaccharide Produced by Bacillus tequilensis PS21 Using Riceberry Broken Rice, and Soybean Meal on Growth Performance, Immunity, and Resistance to Streptococcus agalactiae of Nile tilapia (Oreochromis niloticus).

Overuse of antibiotics in aquaculture has generated bacterial resistance and altered the ecology. Aquacultural disease control requires an environmentally sustainable approach. Bacterial exopolysaccharides (EPSs) as bioimmunostimulants have not been extensively explored in aquaculture. This study investigated EPS produced from 5% w/v riceberry broken rice as a carbon source and 1% w/v soybean meal as a nitrogen source by Bacillus tequilensis PS21 from milk kefir grain for its immunomodulatory, antioxidant activities and resistance to pathogenic Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus). The FTIR spectrum of EPS confirmed the characteristic bonds of polysaccharides, while the HPLC chromatogram of EPS displayed only the glucose monomer subunit, indicating its homopolysaccharide feature. This EPS (20 mg/mL) exhibited DPPH scavenging activity of 65.50 ± 0.31%, an FRAP value of 2.07 ± 0.04 mg FeSO4/g DW, and antimicrobial activity (14.17 ± 0.76 mm inhibition zone diameter) against S. agalactiae EW1 using the agar disc diffusion method. Five groups of Nile tilapia were fed diets (T1 (Control) = 0.0, T2 = 0.1, T3 = 0.2, T4 = 1.0, and T5 = 2.0 g EPS/kg diet) for 90 days. Results showed that EPS did not affect growth performances or body composition, but EPS (T4 + T5) significantly stimulated neutrophil levels and serum lysozyme activity. EPS (T5) significantly induced myeloperoxidase activity, catalase activity, and liver superoxide dismutase activity. EPS (T5) also significantly increased the survival of fish at 80.00 ± 5.77% at 14 days post-challenge with S. agalactiae EW1 compared to the control (T1) at 53.33 ± 10.00%. This study presents an efficient method for utilizing agro-industrial biowaste as a prospective source of value-added EPS via a microbial factory to produce a bio-circular green economy model that preserves a healthy environment while also promoting sustainable aquaculture.

Enhanced performance of eco‐friendly PVC by utilizing halo‐benzothiazole derivatives and glucose/fatty acids esters

AbstractTwo halo‐benzothiazoles, namely, 2‐amino‐6‐bromo‐benzo[d]thiazole and 2‐amino‐6‐fluoro‐benzo[d]thiazole were utilized to modify poly(vinyl chloride) (PVC) and gave two modified PVC samples for biomedical applications. Prepared glucose‐fatty acid esters of palmitic, oleic, and octanoic acids were exploited as plasticizers to produce phthalate‐free eco‐friendly antimicrobial PVC. The chemical structures of all prepared compounds were confirmed via Fourier‐transform infrared spectroscopy. The thermal properties of modified PVC was determined using thermo gravimetric analysis and differential scanning calorimetry while weight loss and degree of discoloration were used to assess the photostability after UV irradiation whereas references heat and UV absorbers were applied for comparison. The plasticizing effect of each glucose‐fatty acid ester at 20% by weight on the mechanical properties of modified PVC was determined and referenced to diethylhexylphthalate. The results revealed that the mechanical properties as well as the thermal stability of plasticized modified PVCs were enhanced. Plasticizers migration from the polymeric matrix was also determined and the results showed low extent of migration of the prepared plasticizers. So, modified plasticized PVC samples exhibited improved physicochemical properties. Antimicrobial properties of all samples, using disc diffusion agar method, were evaluated against some Gram +ve bacteria like Staphylococcus aureus and Streptococcus mutans and Gram −ve bacteria like Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa and fungi strains used were Candida albicans, Aspergillus niger, and Aspergillus ochraceous. All investigated compounds showed improved antibacterial and antifungal activities.Highlights PVC was chemically modified with two halo‐benzothiazoles to obtain antimicrobial PVC. Glucose‐fatty acids esters were prepared as eco‐friendly plasticizers for PVC. Halo‐benzothiazoles improved both the thermal‐ and photo‐stability of PVC. Glucose‐fatty acid plasticizers enhanced the mechanical properties of PVC. The extent of migration of prepared plasticizers is lower than that of reference plasticizer.

Isolation, identification and antimicrobial susceptibility pattern of Salmonella, E. coli, and S. aureus from selected dairy farms in Bedele and Nekemte Districts, Western Ethiopia

Background: Bacterial diseases transmitted through food pose a serious threat to human and animal health. Salmonella, E. coli, and S. aureus are among the major foodborne pathogens. It is becoming a worldwide problem to date. In this regard, there is a lack of information among farms in western Ethiopia. Therefore, the study was conducted to isolate, identify, and assess the antimicrobial susceptibility profile of Salmonella, E. coli, and S. aureus from selected dairy farms in the study area. Methodology: A cross-sectional study was done from December 2018 to June 2019 on small-scale dairy farms from Bedele and Nekemte town, Western Ethiopia with the objective of isolating and identifying Salmonella, E. coli, and S. aureus from lactating cows, milkers’ and milking equipment at farms and to determine the antimicrobial susceptibility of the isolates. A total of 383 samples consisting of cow milk, feces, cow nasal swabs, milkers’ hand swabs, milkers nasal swabs, bucket swabs, and floor swabs were collected from 20 dairy farms. The samples were examined for the presence of Salmonella, E. coli, and S. aureus following standard techniques and procedures. The agar disc diffusion method was used for the antimicrobial susceptibility testing. Results: The overall occurrence of Salmonella, E. coli, and S. aureus was 2.35%, 11.75%, and 2.35% respectively. Out of the 9 Salmonella isolates, 5(4.95%), 3(2.97%), and 1(5%) were isolated from udder milk, rectal feces, and floor swab respectively. S. aureus isolate was highest in udder milk 3(2.97%), followed by cow nasal swab 2(1.98%), feces 1(0.99%), bucket swab 1(5%), floor swab 1(5%) and milker’s nasal swab 1(5%). E. coli was highest in milk sample 19(18.81%), followed by fecal samples 16(15.84%), bucket swab 5(25%), floor Swab 4(20%) and 1(0.99%) in cow nasal swab. All Salmonella isolates were 100% sensitive to nalidixic acid, however 55.55%, 22.22%, and 11.11, respectively, were resistant to cefoxitin, tetracycline, and gentamycin. Tetracycline, cefoxitin, and streptomycin resistance were observed in 33.33%, 9.52%, and 19.05% of E. coli isolates, respectively. On the other hand, all isolates were 100% sensitive to nitrofurantoin, ceftriaxone, nalidixic acid, and ciprofloxacin. The antibiotic susceptibility profiles of S. aureus showed that 55.55% and 11.11% were resistant to Penicillin G and Erythromycin, respectively and all isolates were 100% sensitive to cefoxitin, nitrofurantoin, and gentamicin. Conclusion: The current study shows lower prevalence, lower antimicrobial resistance, and higher susceptibility for most antimicrobials. Recommendation: Stringent control measures, such as treatment of positive cases with effective medications and preventative measures including strict hygiene standards, such as cleaning of the floor, pens, and milking equipment, as well as adequate hand washing throughout the milking process, should be adopted.

Antibiocompetent and bacteriocidal relevance of ascorbic acid on coliforms isolated from feces of apparently healthy students in Rivers Nigeria

In recent times, Ascobic acid has been discovered to posses antibiocidal potential against various bacterial strains that has been resistant which is in sharp contrast as it was previously regarded as potential antioxidant especially as it is thought to reduce oxygen radicals both in vivo and in vitro biochemical processes. This study investigates the anti-biocompetent and bacteriocidal relevance of ascorbic acid on Staphylococcus aureus, Escherichia coli, and Proteus mirabilis recovered from the apparently healthy student feces at Madonna University. Standard microbiological methods were applied for the isolation of fecal coliforms using sterile blood agar, mannitol salt agar and eosin methylene blue (EMB) agar plates. The agar diffusion disc technique was used to determine an ascorbic acid fortified antimicrobial susceptibility testing of test bacteria at various concentrations varying from 0.167g/ml to 1.0g/ml, while their mean values were compared using one-way analysis of variance. The results revealed that Proteus mirabilis were resistant to the various ascorbic acid concentrations, whereas S. aureus and E. coli were susceptible to various ascorbic acid concentrations. An ascorbic acid content (g/ml) changes/shift (at p < 0.05) the zones of inhibition (mm) of the isolates (E. coli and S. aureus) Such observed antibacterial potential suggests that ascorbic acid may be applied in the treatment of enteric or coliforms infections associated with E. coli and Staphylococcus aureus.

Room temperature magnetic ordering and in vitro antibacterial potency of Nd3+ doped CeO2 against the pathogenic bacterial strains

In this study, 5% Nd3+ doped Cerium oxide (Ce0.95Nd0.05O2) was prepared by a modified solid-state reaction method. Crystallite size and lattice strain were determined from the Williamson-Hall (W-H) plot. The four distinct peaks in the photoluminescence (PL) spectra in the visible region signify the structural defects within the crystal lattice. Room temperature ferromagnetism (RTFM) was observed from the hysteresis loop, and the mathematical fitting of the hysteresis loop suggests ferromagnetic dominance (∼83%) in the magnetic response. The virgin M-H loop was fitted by the ferromagnetic Brillouin function, which suggests possible domain formation in the sample. The in vitro antibacterial activity of 5% Nd3+doped CeO2 was evaluated against two clinically isolated multidrug-resistant pathogenic bacterial strains, namely MLD 2 (Escherichia coli) and MLD 4 (Staphylococcus aureus), utilizing the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), disc agar diffusion (DAD) assays, etc. Notably, compared to the MLD 4 bacterial strain, the synthesized material revealed comparable better antibacterial results against the Gram-negative MLD 2 and in comparison, to the MLD 2 bacterial strain, a relatively higher concentration of the sample is required to completely eradicate the bacterial population of MLD 4. This implies that Ce0.95Nd0.05O2 can destroy the growth of the two tested bacterial strains. In the context of cytotoxicity, up to a certain concentration, the synthesized particle demonstrated no appreciable toxicity towards healthy PBMCs.

Investigation of papA, papC, and papG virulence genes revealed their association with antimicrobial resistance among uropathogenic Escherichia coli strains isolated from patients in Thi-Qar province, Iraq

Infection of the urinary tract is one of the more common infections in the people of the world, which is more common in women due to the anatomical structure of the woman's body. The main cause of this infection is uropathogenic E. coli, followed by Klebsiella pneumoniae. This disease is controlled and treated by antibiotics, but one of the most important concerns in today's world is the spread of antibiotic resistance in different strains of bacteria. This resistance to antibiotics is caused by specific genes that increase the number of these identified genes every day. This study aims to find the frequency of three coding genes related to p fimbriae, namely papA, papC, and papG, from E. coli strains extracted from patients with urinary tract infections. Also, in this research, by conducting tests related to the detection of the antimicrobial resistance of the extracted strains and using statistical analysis, an attempt has been made to find a significant relationship between the presence or absence of a gene and resistance to antibacterials. At first, 110 urine samples were collected from patients with UTI in the Dhi Qar province of Iraq. In this research, bacterial culture methods in McConkey agar and advanced biochemical tests were used for primary confirmation of E. coli contamination, and Vitek2 and API E20 systems were used for secondary confirmation of bacterial contamination in suspected samples. Finally, the result of these tests was that all 110 samples were infected with E. coli. Then, samples resistant to the antibiotics Ampicillin, Tetracycline, Ciprofloxacin, Nitrofurantoin, and Cotrimoxazole, respectively, were detected by culturing in MuellerHinton agar medium and disc diffusion using the CLSI 2021 protocol. 36.36, 24.54, 29.09, 2.72, and 20% of the samples were resistant to these antibiotics, respectively. PCR was used to amplify gene fragments, and agarose gel electrophoresis was used to determine the presence of genes. The result was that the percentages of papG, papC, and papA genes were 61.81, 38.18, and 28.18, respectively. Finally, by performing a chisquare test in SPSS software, it was found that there is a significant relationship between the presence or absence of papA and papC genes with ampicillin and a significant relationship between papG and cotrimoxazole. These findings and the findings of other researchers can help us choose the right treatment and design new treatments by determining the antibiotic resistance factor

Endophytic Bacillus aerophilus from the Leaves of Azadirachta indica as a Potential Biocontrol against Staphylococcus aureus

Aims: The study entailed isolation and identification of Bacillus aerophilus in the leaves of young Azadirachta indica plants, establishing the antimicrobial activity of the endophyte against Staphylococcus aureus, and screening for phytochemicals. The study investigated the potential of the endophytic Bacillus aerophilus in pathogen inhibition and phytochemical screening for bioactive compounds produced by the endophyte that can be used in drug development. The research contributes to the wider scientific goal of curbing rising cases of antibiotic resistance.
 Place and Duration of Study: Sample: collected from Kanyonyoo in Kitui County, between August 2022 and June 2023.
 Methodology: The bacteria were aseptically isolated and sub-cultured on nutrient agar. For identification, the bacteria underwent biochemical tests and molecular characterization. The 16S rRNA region was amplified and sequenced using universal primers 27F and 1492R. Bacterial isolate K1L003 was identified as Bacillus aerophilus. For antimicrobial testing, the agar disk diffusion method was used against pathogenic Staphylococcus aureus on Mueller Hinton Agar plates (MHA). The controls were doxycycline and vancomycin.
 Results: The endophytic isolate only inhibited Staphylococcus aureus (P < .001), with an inhibition mean similar to doxycycline (26 mm), against the pathogen. The endophytic isolate produced terpenoids, saponins, alkaloids, and flavonoids.
 Conclusion: Endophytic Bacillus aerophilus has better antimicrobial inhibition potential than vancomycin, against Staphylococcus aureus and produces diverse bioactive secondary metabolites. The endophyte has the potential to produce compounds that are useful in treating drug-resistant Staphylococcal infections.

Biological properties of experimental dental alginate modified for self-disinfection using green nanotechnology

ObjectivesDisinfection of alginate impression materials is a mandatory step to prevent cross-infection in dental clinics. However, alginate disinfection methods are time-consuming and exert a negative impact on accuracy and mechanical properties. Thus, this study aimed to prepare disinfecting agents (CHX and AgNO3) and silver nanoparticles reduced by a natural plant extract to produce a self-disinfecting dental alginate.MethodsConventional alginate impression material was used in this study. Silver nitrate (0.2% AgNO3 group) and chlorohexidine (0.2% CHX group) solutions were prepared using distilled water, and these solutions were later employed for alginate preparation. Moreover, a 90% aqueous plant extract was prepared from Boswellia sacra (BS) oleoresin and used to reduce silver nitrate to form silver nanoparticles that were incorporated in the dental alginate preparation (BS+AgNPs group). The plant extract was characterized by gas chromatography/mass spectrometry (GC/MS) analysis while green-synthesized silver nanoparticles (AgNPs) were characterized by UV-visible (UV–vis) spectroscopy and scanning electron microscopy (SEM). An agar disc diffusion assay was used to test the antimicrobial activity against Candida albicans, Streptococcus mutans, Escherichia coli, methicillin-resistant and susceptible Staphylococcus aureus strains, and Micrococcus luteus. Agar plates were incubated at 37 ± 1 °C for 24 h to allow microbial growth. Diameters of the circular inhibition zones formed around each specimen were measured digitally by using ImageJ software.ResultsChemical analysis of the plant extract revealed the presence of 41 volatile and semi-volatile active compounds. UV–Vis spectrophotometry, SEM, and EDX confirmed the formation of spherical silver nanoparticles using the BS extract. CHX, AgNO3, and the BS+AgNPs modified groups showed significantly larger inhibition zones than the control group against all tested strains. BS+AgNPs and CHX groups showed comparable efficacy against all tested strains except for Staphylococcus aureus, where the CHX-modified alginate had a significantly higher effect.Conclusions and clinical relevanceCHX, silver nitrate, and biosynthesized silver nanoparticles could be promising inexpensive potential candidates for the preparation of a self-disinfecting alginate impression material without affecting its performance. Green synthesis of metal nanoparticles using Boswellia sacra extract could be a very safe, efficient, and nontoxic way with the additional advantage of a synergistic action between metal ions and the phytotherapeutic agents of the plant extract.

국내 개, 고양이, 사람 및 환경에서 유래된 항생제 내성 그람음성세균

The report of distribution and antimicrobial resistance rates in clinical hospitals in South Korea has been well-documented. However, the description of prevalence and antimicrobial resistance rate in veterinary hospitals is relatively rare. The aims of this study were to describe the prevalence and antimicrobial resistance rate for gram-negative bacteria originated from canines, felines, environments, and humans in South Korea. We collected bacteria from the rectal swabs of companion animals (dogs and cats), stool samples of humans (pet owners and medical staffs), and swabs of veterinary hospital surfaced in 16 veterinary hospitals. The isolates for antimicrobial susceptibility were performed by the agar disk diffusion method. Third- and fourth-generation extended-spectrum cephalosporin (ESC) resistance genes were identified by PCR and sequencing. A total of 740 Escherichia coli , 133 Klebsiella pneumoniae, 132 Acinetobacter baumannii , and 100 Pseudomonas aeruginosa isolates were recovered on MacConkey agar from companion animals, humans, and veterinary hospital environment samples for 2019 - 2020. The ESC resistant rates showed 36.3%, 40.6%, 18.2%, and 0% in E. coli , K. pneumoniae , A. baumannii , and P. aeruginosa, respectively. The most of the ESC resistance genes were blaCMY-2, blaDHA-1, and blaCTX-M-type. Our results indicate that the antimicrobial resistance rate including ESC was similar to that in the clinical field except carbapenem. In addition, the genus, species, and an timicrobial resistance determinants of gram-negative bacteria collected from samples were similar between the clinical and veterinary fields.

Investigation of Antimicrobial and Antioxidant Activities of some Lichens

This study investigated the antimicrobial and antioxidant properties of methanol extracts from five lichen species: Polycauliona candelaria (Syn. Xanthoria candelaria), Nephromopsis chlorophylla (Syn. Cetraria chlorophylla), Circinaria calcarea (Syn. Aspicilia calcarea), Bryoria capillaris (Syn. Alectoria cana), and Peltigera canina (Syn. Dermatodea canina). Antimicrobial activities were determined using the agar disc diffusion method, while minimal inhibitory concentration (MIC) values were determined using the micro-well dilution method. Among the lichen species, methanol extract of Circinaria calcarea exhibited the highest antimicrobial activity, with a 15 mm zone of inhibition against Escherichia coli and Bacillus cereus. It also demonstrated the lowest MIC value (31.25 μg/mL) against Bacillus cereus, Bacillus subtilis, Clostridium perfringens and Escherichia coli were the most sensitive microorganisms to lichens. Various antioxidant determination methods were employed to assess the antioxidant activities of the lichens, including ferric ion (Fe+3) reduction capacity, cupric ion (Cu+2) reduction capacity, ferric ion reducing antioxidant power (FRAP), DPPH radical scavenging activity, DMPD radical scavenging activity and metal chelating activity using the bipyridyl reagent. All lichens exhibited excellent antioxidant activity, particularly in metal chelating activity using the bipyridyl reagent. Peltigera canina demonstrated the highest antioxidant activity among the studied lichen species across most of the applied method.

Development and Study of Mosquitocidal and Antibacterial Properties of Typhonium trilobatum-Synthesized ZnO NPS and their Impact on the Predation Efficiency of Guppy Poecilia reticulata against the Dengue vector, Aedes aegypti

Dengue fever is an arbovirus spread mostly by Aedes mosquitos. Every year, there is an increase in the incidence of dengue infection and transmission. As a result, the need for an effective measure remains a top concern. The current work aims to assess the effectiveness of Typhonium trilobatum leaf extract synthesized zinc oxide nanoparticles (ZnO NPs) against the Dengue vector, Aedes aegypti. We synthesized zinc nanoparticles by reducing and stabilizing it using T. trilobatum leaf extract. UV-vis spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray analysis, field emission scanning electron microscopy, transmission electron microscopy and EDAX analysis were used for analyzing nanoparticles. T. trilobatum leaf extract and biosynthesized ZnONPs were extremely efficient against Ae. aegypti young instars, with LC50 values ranging from 36.633 ppm (larva I) to 102.436 ppm (pupa) and 1.555 ppm (larva I) to 6.906 ppm (pupa). The predation effectiveness of Poecillia reticulata guppy fish against A. aegypti I - IV instar larvae were 49.8 and 25.9 %, respectively. Predation was 78.3 and 39.8 % in ZnO-contaminated environments, respectively. The results of T. trilobatum leaf extract synthesized ZnONPs showed considerable larvicidal action with an increase in predatory potential of the guppy fish P. reticulata. To screen the antibacterial activities of T. trilobatum leaf extract and Biosynthesized ZnO NPs against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi, the agar disk diffusion and minimum inhibitory concentration procedures were used. The biosynthesized ZnO NPs showed excellent antibacterial effects against bacterial pathogens. Overall, our study suggests that T. trilobatum leaf extract synthesized ZnO NPs could be used in mosquito control as well as the creation of novel chemotherapeutic medicines with low systemic toxicity.

Determination of the Potential for use of Plant Essential Oils as a Fungicide Against Fusarium Oxysporum (OG10)

This study aimed to determine whether the essential oils of thyme, ginger, and mint from medicinal aromatic plants can provide resistance to the pathogen Fusarium oxysporum in the maize plant. To this end, the antifungal effect of 0.1 ml, 0.25 ml, 0.5 ml, and 1 ml essential oil amounts was determined by the agar disc diffusion method. It was determined that concentrations containing 0.1, and 0.25 ml essential oil showed no antifungal effects, however, concentrations containing 0.5 and 1 ml essential oil had antifungal effects. The most effective concentration was found to be 1 ml of essential oil in all three species. The maize was grown under hydroponic conditions. Thyme, ginger, and mint essential oils (1 g/100 ml) were applied to the root medium of the grown maize plant on the 8th day. An F. oxysporum suspension containing 107 spores was applied after 24 hours and harvested 3 days later. When the reactive oxygen species (H2O2) and MDA amounts of the harvested plants were examined, it was observed that there was an increase in the population of F. oxysporum. However, applications of thyme, ginger, and mint essential oil have been observed to significantly reduce these. It was also determined that essential oils protected the plant against F. oxysporum by increasing antioxidant enzyme activities. Although these three essential oils applied have antifungal properties, it has been observed that the best effect belongs to thyme essential oil. The results show that essential oils of thyme ginger and mint can be used as potential fungicides against the pathogen F. oxysporum in maize cultivation

Increased antibiofilm and growth inhibitory effect of Imipenem/Cilastatin nanoliposomes against clinical Pseudomonas aeruginosa isolates

Numerous infections are linked to Pseudomonas aeruginosa. It is one of the major medical concerns because of virulence and antibiotic resistance. Antibiotic encapsulation in liposomes is a good strategy for controlling infections caused by this microorganism. Evaluation of anti-Pseudomonas aeruginosa effect of liposomal form of Imipenem/Cilastatin in vitro condition. By using the disk agar diffusion technique, the isolates’ pattern of antibiotic resistance was identified. The antibiotic was placed into the nanoliposome after it had been made using the thin layer and ethanol injection techniques. SEM and DLS were used to determine the size, shape, and zeta potential of the encapsulated drug form and the empty nanoliposome. Additionally, Imipenem/Cilastatin encapsulation in nanoliposomes was studied using FT-IR spectroscopy. In the microbial assay experiments the MIC, MBC and MBEC of liposomal and free drug forms were determined. The nanoparticles were spherical, with a diameter ranging from 30 to 39 nm, and the EE% in the thin layer and ethanol injection procedures were 97 and 98, respectively. Imipenem/Cilastatin nanoliposomes showed peaks at 3009 cm−1 and 1650 cm−1, demonstrating the thermodynamic stability for the chemical structure of the drug enclosed and validating the encapsulation of antibiotic in the nanoliposomes. When compared to free drug forms, nanoliposomes had lower MIC and MBC values in the majority of the isolates and had a greater ability to eradicate the biofilm formation. It was shown that the two nanoliposome preparation techniques were more efficient in 80% of the isolates, which had outcomes that were consistent with those of numerous other investigations. Overall, we demonstrated that the antibacterial activity of nanoliposomes was higher than that of the free drug form based on the evaluation of their MIC and MBC. Pharmaceutical nanoliposome techniques provide an excellent future perspective on how to manage microbial infections that are resistant to antibiotics.Graphical