This study aimed to investigate the antifungal activity of seeds of Abrus precatorius L., Datura ... more This study aimed to investigate the antifungal activity of seeds of Abrus precatorius L., Datura metel L. and Diploknema butyracea (Roxb.) H.J. Lam against common phytopathogenic fungi. The powdered seeds were extracted by Soxhlet extraction method using methanol as a solvent. Antifungal activity was performed by poison agar technique with different concentrations ranging from 5 to 20% of seed extracts against two fungal pathogens -Fusarium oxysporum f. sp. cubense R4 (FocR4) and Rhizoctonia spp. Among three plant seed methanolic extracts at 5% concentration, D. metel L. seeds showed significant inhibition with 69.81±3.30% percentage inhibition of diameter growth (PIDG) against FocR4 on 8 th day and 77.51±3.00% PIDG Rhizoctonia spp. on 5 th day. All the plant seed extracts showed complete inhibition against mycelial growth at ≤10% concentration. UV-visible spectroscopy spectra showed the peaks at 238 nm and 280 nm wavelengths for the seed extracts of A. precatorius L., and D. metel L., respectively while D. butyracea (Roxb.) H.J. Lam showed the peaks centered at 206 nm and 262 nm which were assumed to represent the antifungal compounds. The antifungal activity of the plant extracts could be attributed by the phytochemicals present in crude seed extracts. Our results indicate that seeds of the examined three plants are potential biofungicides which could substitute chemical fungicides.
Global agriculture is frequently subjected to stresses from increased salt content, drought, heav... more Global agriculture is frequently subjected to stresses from increased salt content, drought, heavy metals, and other factors, which limit plant growth and production, deteriorate soil health, and constitute a severe danger to global food security. Development of environmentally acceptable mitigation techniques against stresses and restrictions on the use of chemical fertilizers in agricultural fields is essential. Therefore, eco-friendly practises must be kept to prevent the detrimental impacts of stress on agricultural regions. The advanced metabolic machinery needed to handle this issue is not now existent in plants to deal against the stresses. Research has shown that the key role and mechanisms of arbuscular mycorrhiza fungi (AMF) to enhance plant nutrient uptake, immobilisation and translocation of heavy metals, and plant growth-promoting attributes may be suitable agents for plant growth under diversed stressed condition. The successful symbiosis and the functional relationshi...
Bioinorganic Chemistry and Applications, Mar 10, 2022
Nanoparticles show the multidisciplinary versatile utility and are gaining the prime place in var... more Nanoparticles show the multidisciplinary versatile utility and are gaining the prime place in various fields, such as medicine, electronics, pharmaceuticals, electrical designing, cosmetics, food industries, and agriculture, due to their small size and large surface to volume ratio. Biogenic or green synthesis methods are environmentally friendly, economically feasible, rapid, free of organic solvents, and reliable over conventional methods. Plant extracts are of incredible potential in the biosynthesis of metal nanoparticles owing to their bountiful availability, stabilizing, and reducing ability. In the present study, the aqueous leaf extract of Buchanania lanzan Spreng was mixed with 0.5 mM silver nitrate and incubated at 70°C for 1 h and synthesized a good quantity of AgNPs. e synthesized AgNPs were characterized using UV-visible spectroscopy, X-ray diffractometry (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). e maximum absorption of UV-visible spectra was obtained in the range of 420-430 nm. Furthermore, SEM and TEM results inferred that the size of the particles were 23-62 nm, spherical, crystalline, uniformly distributed, and negatively charged with the zeta potential of −27.6 mV. In addition, the antifungal activities of the AgNPs were evaluated against two phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum f. sp. lycopersici in vitro using poison food techniques on PDA media. e maximum rate of mycelia inhibition was found in 150 ppm concentration of AgNPs against both phytopathogenic fungi.
Increase in extended-spectrum β-lactamases (ESBL) producing microbes in recent years has led to l... more Increase in extended-spectrum β-lactamases (ESBL) producing microbes in recent years has led to limitations of treatment options. This study aimed to assess the prevalence of ESBL producing E. coli and Klebsiella spp. at a tertiary hospital in Nepal. A total of 2209 non-repetitive mid-stream urine (MSU) samples were collected during the study period (March to September 2014). Identification of the isolates was done by Gram's staining followed by biochemical tests. Antibiotic susceptibility testing was done by modified Kirby-Bauer disc diffusion method and interpretation was done following Clinical and Laboratory Standard Institute (CLSI) guidelines, 2013. ESBL screening among E. coli and Klebsiella spp. isolates were done using ceftriaxone, cefotaxime, ceftazidime and cefpodoxime. The confirmation was done by phenotypic disc diffusion test (combined disc method) using ceftazidime (30µg) and ceftazidime plus clavulanic acid (30/10µg), and cefotaxime (30µg) and cefotaxime plus cla...
In the present study, 24 Azotobacter strains were isolated from soils of different areas of south... more In the present study, 24 Azotobacter strains were isolated from soils of different areas of southern Rajasthan and characterized at biochemical, functional, and molecular levels. The isolated Azotobacter strains were gram negative and cyst forming when viewed under the microscope. These strains were also screened for their plant growth promoting activities and the ability of these isolates to survive under abiotic stress conditions viz. salt, pH, temperature, and drought stress. All the isolates showed IAA, siderophore, HCN, and ammonia production, whereas seven Azotobacter strains showed phosphate solubilization. Amplified Ribosomal DNA Restriction Analysis (ARDRA) revealed significant diversity among Azotobacter strains and the dendrogram obtained differentiated twenty-four of the strains into two major clusters at a similarity coefficient of 0.64. Qualitative and quantitative N2 fixation abilities of these strains were also detrained, and the amounts of acetylene reduced by Azoto...
In the present study, 24 Azotobacter strains were isolated from soils of different areas of south... more In the present study, 24 Azotobacter strains were isolated from soils of different areas of southern Rajasthan and characterized at biochemical, functional, and molecular levels. The isolated Azotobacter strains were gram negative and cyst forming when viewed under the microscope. These strains were also screened for their plant growth promoting activities and the ability of these isolates to survive under abiotic stress conditions viz. salt, pH, temperature, and drought stress. All the isolates showed IAA, siderophore, HCN, and ammonia production, whereas seven Azotobacter strains showed phosphate solubilization. Amplified Ribosomal DNA Restriction Analysis (ARDRA) revealed significant diversity among Azotobacter strains and the dendrogram obtained differentiated twenty-four of the strains into two major clusters at a similarity coefficient of 0.64. Qualitative and quantitative N2 fixation abilities of these strains were also detrained, and the amounts of acetylene reduced by Azoto...
Infections caused by beta-lactamases producing Gram-negative bacteria are increasing, thus posing... more Infections caused by beta-lactamases producing Gram-negative bacteria are increasing, thus posing a challenge to the management of such infections. The surveillance data of such bacteria is limited in Nepal so this study aimed to detect the beta-lactamase producing Gram-negative bacteria in a tertiary setting. A total of 604 clinical samples, including urine, blood, sputum and body fluids, were cultured and identified by the routine standard laboratory protocols. Antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method following Clinical and Laboratory Standard Institute guidelines (2014). Extended-spectrum beta-lactamases (ESBL) producers were identified by combined disk method and metallo-beta-lactamases (MBL) producers were identified by Imipenem- EDTA combined disk method. Out of 604 samples, 282 (46.7%) samples showed significant growth, of which 229 (81.2%) were Gram-negative bacteria. Of 229 Gram-negative bacteria, 200 (87.3%) were multidrug resistant, ...
Introduction:
Increase in extended-spectrum β-lactamases (ESBL) producing microbes in recent year... more Introduction: Increase in extended-spectrum β-lactamases (ESBL) producing microbes in recent years has led to limitations of treatment options. This study aimed to assess the prevalence of ESBL producing E. coli and Klebsiella spp. at a tertiary hospital in Nepal. Methods: A total of 2209 non-repetitive mid-stream urine (MSU) samples were collected during the study period (March to September 2014). Identification of the isolates was done by Gram's staining followed by biochemical tests. Antibiotic susceptibility testing was done by modified Kirby-Bauer disc diffusion method and interpretation was done following Clinical and Laboratory Standard Institute (CLSI) guidelines, 2013. ESBL screening among E. coli and Klebsiella spp. isolates were done using ceftriaxone, cefotaxime, ceftazidime and cefpodoxime. The confirmation was done by phenotypic disc diffusion test (combined disc method) using ceftazidime (30µg) and ceftazidime plus clavulanic acid (30/10µg), and cefotaxime (30µg) and cefotaxime plus clavulanic acid (30/10µg) disc as per CLSI guidelines. Results: A total of 451 samples showed significant bacteriuria with 365 (80.9%) E. coli, 17 (3.8%) Klebsiella pneumoniae and 3 (0.7%) Klebsiella oxytoca. Of 451 isolates, 236 (52.3%) were found MDR strains. By combined disk test, 33 (91.7%) E. coli and 3 (8.3%) Klebsiella spp. were found ESBL producers. Conclusion: Higher prevalence of ESBL producing E. coli and Klebsiella spp. was observed warranting prompt need of surveillance for effective management of such MDR strains. Keywords: E. coli, Extended-spectrum β-lactamase, ESBL, Klebsiella, Nepal, Urinary tract infection, UTI.
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Papers by Elina Maharjan
Increase in extended-spectrum β-lactamases (ESBL) producing microbes in recent years has led to limitations of treatment options.
This study aimed to assess the prevalence of ESBL producing E. coli and Klebsiella spp. at a tertiary hospital in Nepal.
Methods:
A total of 2209 non-repetitive mid-stream urine (MSU) samples were collected during the study period (March to September 2014).
Identification of the isolates was done by Gram's staining followed by biochemical tests. Antibiotic susceptibility testing was done by
modified Kirby-Bauer disc diffusion method and interpretation was done following Clinical and Laboratory Standard Institute
(CLSI) guidelines, 2013. ESBL screening among E. coli and Klebsiella spp. isolates were done using ceftriaxone, cefotaxime,
ceftazidime and cefpodoxime. The confirmation was done by phenotypic disc diffusion test (combined disc method) using
ceftazidime (30µg) and ceftazidime plus clavulanic acid (30/10µg), and cefotaxime (30µg) and cefotaxime plus clavulanic acid
(30/10µg) disc as per CLSI guidelines.
Results:
A total of 451 samples showed significant bacteriuria with 365 (80.9%) E. coli, 17 (3.8%) Klebsiella pneumoniae and 3 (0.7%)
Klebsiella oxytoca. Of 451 isolates, 236 (52.3%) were found MDR strains. By combined disk test, 33 (91.7%) E. coli and 3 (8.3%)
Klebsiella spp. were found ESBL producers.
Conclusion:
Higher prevalence of ESBL producing E. coli and Klebsiella spp. was observed warranting prompt need of surveillance for effective
management of such MDR strains.
Keywords: E. coli, Extended-spectrum β-lactamase, ESBL, Klebsiella, Nepal, Urinary tract infection, UTI.