Antioxidant and antibacterial activity of silver nanoparticles synthesized by Cestrum nocturnum

Background: Silver nanoparticles are toxic to bacteria and have widespread application in differentresearch areas.Objective: The aim of this study was to synthesize silver nanoparticles using an aqueous leaf extract ofCestrum nocturnum and to test its antioxidant and antibacterial activities.Materials and methods: The silver nanoparticles were synthesized by addition of 20 ml extract (8% w/v)with 180 ml silver nitrate solution (1 mM). The synthesis of silver nanoparticles was confirmed byUVeVis spectrophotometer. The silver nanoparticles were characterized by X-ray diffractometer,Transmission Electron Microscope, Scanning Electron Microscope and Fourier Transform Infra-Redspectroscopy. The antioxidant property of silver nanoparticles was analyzed by the 2, 2-diphenyl-1-picrylhydrazyl, hydrogen peroxide, hydroxyl radical and superoxide radical scavenging methods. Thebacteriostatic and bactericidal activity of silver nanoparticles against Escherichia coli, Enterococcus faecalis, and Salmonella typhi was determined using bacterial growth inhibition method. The antibacterialsensitivity and Minimum Inhibitory Concentration (MIC) of silver nanoparticles was determined againstthe bacteria.Results: The results confirmed that the silver nanoparticles synthesized by C. nocturnum extract werecrystalline in nature, average particle size was 20 nm and were mostly spherical in shape. The antioxidant methods confirmed that the silver nanoparticles have more antioxidant activity as compared tovitamin C. The silver nanoparticles have strong antibacterial (maximum Vibrio cholerae and minimumE. faecalis) activity. The MIC value of silver nanoparticles was 16 mg/ml (Citrobacter), 4 mg/ml (E. faecalis),16 mg/ml (S. typhi), 8 mg/ml (E. coli), 8 mg/ml (Proteus vulgaris), and 16 mg/ml (V. cholerae).Conclusion: Green synthesized silver nanoparticles have strong antioxidant and antibacterial activity dueto the presence of bioactive molecules on the surface of silver nanoparticles.© 2018 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Publishing Services byElsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Viral Encephalitis: A Hard Nut to Crack

Viral encephalitis is inflammation of brain that manifests as neurological complication of viral infections. There are quite a good number of viruses, for example, human herpes virus, Japanese encephalitis, and enteroviruses that can result in such a dreadful condition. Geographical location, age, gender, immune status, and climatic conditions also contribute to the establishment of this disease in an individual. Clinical signs and symptoms include fever, headache, altered level of consciousness, changed mental status, body ache, seizures, nausea, and vomiting. Effective management of this disease relies on timely diagnosis that in turn depends on apt and suitable investigation techniques. Traditional investigations have thinned out these days owing to the fact that advanced molecular technologies have been introduced to the diagnostic field. Treatment of viral encephalitis mainly involves symptomatic relieve from fever, malaise, myalgia along with measures to reduce viral load in the patient. This review mentions about all the possible aspects of viral encephalitis starting from etiology to the management and preventive measures that include immunization and vector control.

Resistance to anti leprosy drugs in multi-bacillary leprosy: A cross sectional study from a tertiary care centre in eastern Uttar Pradesh, India

Background: WHO MDT is the main drug regimen for treating leprosy and has been used for more than three decades. Many cases of relapse of leprosy have been reported, which points towards the emergence of drug resistance with the antileprotic drugs. Objectives: To find the resistance with the antileprotic drugs by detecting the mutations in drug resistance determining region of the rpoB, folP1 and gyrA genes of Mycobacterium leprae. Methods: Leprosy patients with bacterial index ≥2 were included in the study. The slides were further processed to extract genomic DNA, and polymerase chain reactions were performed to amplify the drug resistance determining region (DRDR) of rpoB, folP1 and gyrA genes. The samples in which genes could be amplified were subjected to DNA sequencing to detect mutations. Results: Out of 78 samples rpoB gene was amplified in 39 (50%), folP1 in 32 (41%) and gyrA in 45 (57.7%). In 20 (25.6%) samples no gene was amplified. Only 32 samples of rpoB, 25 samples of folP1 and 38 samples of gyrA gene were included in the study, rest were excluded due to sequencing error. No mutation was seen in rpoB gene and in folP1 gene. In gyrA gene samples mutations were seen in 8 (21%) samples, and were present at codon 91 GCA → GTA (Alanine → Valine). Limitations: Small sample size and less efficient method to detect resistance. Conclusion: Resistance is not a problem with conventional drugs in MDT. It is more common with quinolones.

Phage therapy of staphylococcal chronic osteomyelitis in experimental animal model.

Background & objectives: Methicillin resistant Staphylococcus aureus (MRSA) are the commonest cause of osteomyelitis. The aim of this study was to evaluate the role of an alternative therapy i.e. application of S. aureus specific bacteriophages in cases of osteomyelitis caused by MRSA in animal model. Methods: Twenty two rabbits were included in this study. The first two rabbits were used to test the safety of phage cocktail while the remaining 20 rabbits were divided into three groups; group A (n=4) to assess the establishment of osteomyelitis; group B (n=4) osteomyelitis developed but therapy started only after six weeks; and group C (n=12) osteomyelitis developed and therapy started after three weeks. Groups B and C rabbits were treated with four doses of cocktail of seven virulent bacteriophages at the interval of 48 h. Comparison between three groups was made on the basis of observation of clinical, radiological, microbiological, and histopathological examinations. Results: Experimental group rabbits recovered from the illness in the subsequent two weeks of the therapy. Appetite and activity of the rabbits improved, local oedema, erythema and induration subsided. There were minimal changes associated with osteomyelitis in X-ray and histopathology also showed no signs of infection with new bone formation. Control B group rabbits also recovered well from the infection. Interpretation & conclusions: The present study shows a potential of phage therapy to treat difficult infections caused by multidrug resistant bacteria.

Synthesis, DNA cleavage and antimicrobial activity of 4-thiazolidinones-benzothiazole conjugates.

Antimicrobial screening of several novel 4-thiazolidinones with benzothiazole moiety has been performed. These compounds were evaluated for antimicrobial activity against a panel of bacterial and fungal strains. The strains were treated with these benzothiazole derivatives at varying concentrations, and MIC’s were calculated. Structures of these compounds have been determined by spectroscopic studies viz., FT-IR, 1H NMR, 13C NMR and elemental analysis. Significant antimicrobial activity was observed for some members of the series, and compounds viz. 3-(4-(benzo[d]thiazol-2-yl) phenyl)-2-(4-methoxyphenyl)thiazolidin-4-one and 3-(4-(benzo[d]thiazol-2-yl)phenyl)-2-(4-hydroxy phenyl)thiazolidin-4-one were found to be the most active against E.coli and C.albicans with MIC values in the range of 15.6–125 μg/ml. Preliminary study of the structure–activity relationship revealed that electron donating groups associated with thiazolidine bearing benzothiazole rings had a great effect on the antimicrobial activity of these compounds and contributes positively for the action. DNA cleavage experiments gave valuable hints with supporting evidence for describing the mechanism of action and hence showed a good correlation between their calculated MIC’s and its lethality.

Prevalence of Parvovirus B 19 Infection in Children with Aplastic Anemia.

We studied the prevalence of parvovirus B19 infection in pediatric patients with acquired aplastic anemia. Detection of parvovirus B19 DNA by PCR and IgM antibodies by ELISA was carried out in 66 pediatric patients with acquired aplastic anemia. 45 healthy children acted as controls. Parvovirus B19 DNA was detected in significantly higher number of patients in comparison to controls (27% vs 2%, P = 0.001). Similarly, parvovirus B19 IgM antibodies were detected in 17 (25.8%) patients as against one control (2.2%) (P<0.05). Clinical and hematological profile of the patients with or without parvovirus infection was comparable.

Diagnosis of typhoid fever by polymerase chain reaction.

OBJECTIVE: To determine the efficacy of nested polymerase chain reaction (PCR) in detecting Salmonella typhi gene sequences in blood and urine specimens and to determine the cut-off titer of Widal test using PCR as gold standard test for diagnosis of typhoid fever. METHODS: Study included 71 children between the ages of 8 months and 14 years; 52 of them were suspected cases of typhoid fever, 11 were febrile non-typhoid controls and 8 were apparently healthy children. Nested PCR in Blood and Urine, Blood culture, Widal test and Urine culture were done and their results analyzed. RESULTS: Among suspected typhoid cases, PCR in blood and urine had positivity of 82.7% each. Blood culture, Widal test (at cut off titer TO and/or TH > 1:160) and urine culture had positivity of 26.9%, 50% and 3.8% respectively. In one case, urine PCR was positive and blood PCR was negative. Similarly, in another case, PCR in blood was positive however urine tested negative. Considering PCR as gold standard, the antibody cut off titer was evaluated. A cut-off titer of TO > 1:80 and/or TH > 1:160 had sensitivity and specificity of 72.7% and 84.2%, while the respective figures were 50% and 89.5% when the cut-off titer was TO and/or TH > 1:160. CONCLUSION: The sensitivity, specificity, positive and negative predictive values, likelihood ratios were same for PCR based detection of S. typhi in blood and urine samples. Nested PCR had higher efficacy in detecting typhoid fever than Widal test, blood and urine cultures. A cut off titer of TO > 1:80 and/or TH > 1:160 was found to have better diagnostic value in this region.