Kandarpa K. Saikia

Identification of potential vaccine candidates against Streptococcus pneumoniae by reverse vaccinology approach.

In the past few decades, genome-based approaches have contributed significantly to vaccine development. Our aim was to identify the most conserved and immunogenic antigens of Streptococcus pneumoniae, which can be potential vaccine candidates in the future. BLASTn was done to identify the most conserved antigens. PSORTb 3.0.2 was run to predict the subcellular localization of the proteins. B cell epitope prediction was done for the immunogenicity testing. Finally, BLASTp was done for verifying the extent of similarity to human proteome to exclude the possibility of autoimmunity. Proteins failing to comply with the set parameters were filtered at each step. Based on the above criteria, out of the initial 22 pneumococcal proteins selected for screening, pavB and pullulanase were the most promising candidate proteins.

CAN-catalyzed microwave promoted reaction of indole with Betti bases under solvent-free condition and evaluation of antibacterial activity of the products

ABSTRACT CAN-catalyzed reaction of Betti bases with indoles under microwave irradiation gives 3-(α,α-diarylmethyl)indoles. Better yield of the products, especially when one of the aryl ring is phenol were achieved. The reaction is performed in solvent-free condition. The antibacterial studies of the synthesized compounds were performed and some of the compounds showed good activity against Methicillin-resistant Staphylococcus aureus bacteria. GRAPHICAL ABSTRACT

Emergence of vanA gene among vancomycin-resistant enterococci in a tertiary care hospital of North - East India.

Background & objectives: Vancomycin-resistant enterococci (VRE) have become one of the most challenging nosocomial pathogens with the rapid spread of the multi-drug resistant strain with limited therapeutic options. It is a matter of concern due to its ability to transfer vancomycin resistant gene to other organisms. The present study was undertaken to determine the emergence of vancomycin-resistant enterococci and the vanA gene among the isolates in a tertiary care hospital of North-East India. Methods: A total of 67 consecutive enterococcal isolates from different clinical samples were collected and identified by using the standard methods. Antibiogram was done by disk diffusion method and VRE was screened by the disk diffusion and vancomycin supplement agar dilution method. The minimum inhibitory concentration (MIC) value for vancomycin was determined by E-test. The VRE isolates were analyzed by PCR for vanA gene. Results: A total of 54 (81%) Enterococcus faecalis and 13 (19%) E. faecium were detected among the clinical isolates and 16 (24%) were VRE. The VRE isolates were multidrug resistant and linezolid resistance was also found to be in three. MIC range to vancomycin was 16-32 µg/ml among the VRE. The vanA gene was found in nine of 16 VRE isolates. Interpretation & conclusions: Emergence of VRE and presence of vanA in a tertiary care hospital setting in North-East India indicate toward a need for implementing infection control policies and active surveillance.

In silico identification of vaccine candidates against Klebsiella oxytoca

Klebsiella oxytoca causes several diseases in immunocompromised as well as healthy individuals. Increasing resistance to a number of antibiotics makes treatment options limited. Prevention using vaccine could be an important solution to get rid of infections caused by Klebsiella oxytoca. In recent time, genome based approaches have contributed significantly in vaccine development. Our aim was to identify the most conserved and immunogenic antigens that can be considered as potential vaccine candidates. KEGG database was used to find out pathways unique to the bacteria. Subcellular localization of the protein sequences taken from the selected 36 pathways were predicted using PSORTb v3.0.2 and CELLO v2.5. Prediction of B cell epitope and the probability of the antigenicity were evaluated by using IEDB and Vaxijen respectively. BLASTp was done to find out the similarity of the selected proteins with the human proteome. Proteins failing to comply with the set parameters were filtered at each step. Finally, we identified 6 surface exposed proteins as potential vaccine candidates against Klebsiella oxytoca.

Screening of Enhydra fluctuans for Phytochemical Composition and Broad-Spectrum Antibacterial Activity against Clinical Bacterial Isolates

ABSTRACT Enhydra fluctuans extracts were evaluated against numerous drug-resistant clinical isolates of methicillin-resistant Staphylococcus aureus and extended-spectrum beta-lactamase (ESBL)-and metallobetalactamase-producing Escherichia coli and Klebsiella pneumoniae. Antibacterial testing was carried out using the well diffusion method, and minimum inhibitory concentration (MIC) was calculated using the resazurin-based dye method. The extracts were also screened for phytochemical composition. Toluene extracts of the plant showed considerable antibacterial activity against gram-negative bacteria. MIC values ranged from 25 mg.mL–1 to 100 mg.mL–1 for selected isolates. Slight evidence of synergism was observed in combination studies with selected antibiotics.