Vaibhav Mishra

Bio: Vaibhav Mishra is an academic researcher. The author has contributed to research in topics: Candida tropicalis & Petroleum ether. The author has an hindex of 2, co-authored 2 publications receiving 48 citations.

Antimicrobial activity and phytochemical screening of serial extracts from leaves of Aegle marmelos (Linn.).

Abstract: The in vitro antimicrobial activity of serial petroleum ether, chloroform and methanol extracts from leaves of Aegle mawmelos were investigated against bacterial and fungal species. All the extracts exhibited broad spectrum antimicrobial activity with zones of inhibition ranging from 10 to 22 mm against bacteria: Staphylococcus aureus, beta Streptococcus haemolyticus group A, Proteus mimrabilis, Klebsiella pneumoniae, Pseudomonas aenrginosa, Escherichia coli, Salmonella typhi, fungi: Candida albicans, Candida tropicalis and Aspergillusflavus. The minimal inhibitory concentrations (MIC) and the minimal microbicidal concentrations (MMC) of the extracts ranged from 1.25 to 10 mg/mL and 2.5 to 20 mg/mL respectively. Assessment of antibacterial efficacy of different extract revealed that Staphylococcus aureus, beta Streptococcus haemolyticus group A, Pseudomonas aeruginosa and Escherichia coli showed high susceptibility to petroleum ether extract. Proteus mimrabilis, Klebsiella pneumoniae showed high susceptibility to chloroform extract and Salmonella typhi showed high susceptibility to methanol extract. Petroleum ether extract exhibited the highest antifungal efficacy against all tested fungal species. Phytochemical screening revealed the presence of phenols, sterols in petroleum ether and chloroform extracts, whereas tannins, flavonoids, coumarins, saponins and triterpenoids in methanol extract. The ability of the leaf extracts of Aegle manmelos to inhibit growth of bacteria and fungi is an indication of its broad spectrum antimicrobial activity which could be a potential source for development of novel bioactive antimicrobial agents.

Third generation cephalosporin-resistance in Klebsiella pneumoniae isolates: an emerging threat -

Abstract: Background: Newer generation cephalosporin-resistance among Klebsiella pneumoniae organisms has increased recently. Present study is undertaken to find incidence, antimicrobial susceptibility and prevalence of extended spectrum beta-lactamase (ESBL) in K. pneumoniae isolates in a tertiary care hospital. Methods: Prospective study was carried out between June to December 2011. Samples of pus, blood, urine, cerebro-spinal fluid, stool, peritoneal, pleural and synovial fluid were collected from indoor and outdoor patients for isolation and antimicrobial susceptibility pattern of K. pneumoniae in the department of microbiology, G.R. Medical College Gwalior, M.P. Ceftazidime resistant K. pneumoniae were subjected to Phenotypic Confirmatory Disc Diffusion Test (PCDDT) and Double Disc Synergy Test (DDST) for detection of ESBL. Results: Out of 2480 samples collected a total of 530 K. pneumoniae were isolated and subjected to antimicrobial susceptibility. Antibiotic sensitivity to imipenem, cefoperazone, amikacin and ofloxacin were 82, 74, 73 and 72% respectively whereas sensitivity to ceftizoxime, ceftriaxone cefotaxime, ceftazidime ranged between 47-50%. K. pneumoniae were found to be resistant to ampicillin, co-trimoxazole, doxycycline and gentamicin, by 91, 82, 54 and 50% respectively. Among third generation cephalosporins K. pneumoniae were least sensitive (47%) to ceftazidime. About 33 and 32% of the ceftazidime resistant strains were found to be ESBL positive by PCDDT and DDST respectively. Conclusions: This study has shown that prevalence of ESBL producing K. pneumoniae is the most important reason for increased resistance to third generation cephalosporins. There is need to carry out tests for detection of ESBL producing bacteria routinely.

Phytochemical evaluation, antimicrobial activity, and determination of bioactive components from leaves of Aegle marmelos.

Abstract: The therapeutic value of Aegle marmelos Correa (Rutaceae), commonly known as ''Bael," has been recognized as a component of traditional medication for the treatment of various human ailments. The plant, though, being highly explored, still lacks sufficient evidences for the best variety possessing the highest degree of medicinal values. The present study is focused on phytochemical screening of aqueous and methanolic leaf extracts of 18 varieties/accessions of A. marmelos. The crude extracts of A. marmelos revealed the presence of several biologically active phytochemicals with the highest quantity of alkaloids, flavonoids, and phenols in Pant Aparna variety. The antibacterial efficacy was investigated against pathogenic bacterial strains and the highest inhibitory activity of aqueous extract was obtained against S. epidermidis, whereas methanolic extract was found to be most potent against S. aureus at 40 mg/mL concentration. However, in aqueous : ethanol, the best results were observed against E. aerogenes followed by K. pneumonia and S. epidermidis. The MIC of aqueous and methanol extract of Aegle marmelos ranged from 10 mg/mL to 40 mg/mL whereas in aqueous : ethanol it ranged between 40 mg/mL and 160 mg/mL. The GC-MS analysis revealed the presence of many bioactive compounds such as flavonoids, alcohols, aldehydes, aromatic compounds, fatty acid methyl esters, terpenoids, phenolics, and steroids that can be postulated for antibacterial activity.

Chemical composition, antimicrobial and antifungal activities of essential oils of the leaves of Aegle marmelos (L.) Correa growing in Egypt

Abstract: The essential oil obtained by hydrodistillation of Aegle marmelos (L.)Correa leaves were analyzed by GC/MS yield (0.9% v/w). Twenty seven components were identified representing 97.76 % of the total oil composition. The major components were α-phellenderene (20.97%), α-pinene (17.76%) and δ-carene (16.37%) and other abundant components as γ-cadinene (8.01%), trans-2-hydroxycinnmic acid (6.85%) and β-myrcene (4.32%). The essential oil exhibited significant antibacterial activity against Gram-positive bacteria as Streptococcus faecalis with inhibition zone (30 mm) and Gram-negative bacteria as Pseudomonas aeruginosa (28 mm). Moreover, moderate activity was observed against Bacillus subtilis (23 mm), Staphylococcus aureus (23 mm), Sarcina lutea (20 mm), Arthrobacter citreus (20 mm) and Escherichia coli (25 mm) in comparison with antibiotics. The antifungal activity against Aspergillus niger (30 mm) and Candida albicans (30 mm) was higher than the antifungal antibiotics. Moreover, the oil inhibited the germination of Aspergillus niger and Fusarium oxysporum spores at different concentrations.