Biomedical subjects

D Panigrahi

Publications and source records attributed to D Panigrahi.

At least 55 records · Page 3Linked to original sources

PubMed1991

Enterotoxin production & mouse virulence of clinical isolates of Salmonella typhimurium strains.

Twenty five isolates of S. typhimurium from clinical specimens were studied for markers of virulence. Three of five isolates from blood, both isolates from CSF and urine and only two of fifteen isolates from faeces were positive for fluid accumulation in rabbit ileal loop. All these strains produced an enterotoxic principle, antigenically related to cholera coli family of enterotoxins, as detected by latex agglutination and immuno-dot-blot tests. Polymyxin-B treated 6 h cultures yielded the best toxin. All 5 blood isolates, both CSF isolates and one of the two urine isolates showed low LD50 indicating high virulence. The study thus revealed that some strains of S. typhimurium are more virulent and produce more enterotoxins. These strains invade the intestinal mucosa potently and lead to extra-intestinal manifestations. The low virulent strains, on the other hand, are confined to the intestine and cause mild/moderate gastroenteritis. Enzyme assays were done in 5 representative strains of good, moderate and low toxin producers. Catalase and superoxide dismutase assays did not show any correlation with toxin production, thus suggesting that the enzyme production is unlikely to be a reliable indicator of the virulence for S. typhimurium.

Animals↗

PubMed1990

Mechanism of protection provided by active immunization with porins in mice challenged with Salmonella typhi.

Oxygen free radical (OFR) generation capacity of peritoneal macrophages was studied by chemiluminescent technique. Chemiluminescent (CL) response of macrophages from control, infected and immunized-infected mice was observed using non specific (Latex) and specific (S. typhi, cells and porins) stimulants at different time intervals. CL response was found to be significantly higher in immunized-infected group throughout the study period using all the three stimulants as compared to that in the infected as well as uninfected control mice. The mode of action of porin vaccine in increasing capacity of generating OFR is probably through increased expression of porin (protein) as well as carbohydrate receptors on the macrophage surface which leads to the stimulation of the whole caseade of respiratory burst or through the increase in the respiratory burst enzyme activities linked with each receptor or both.

Animals↗

PubMed1990

Cholera-like enterotoxin in certain Campylobacter jejuni strains: some observations.

Fourteen human isolates of Campylobacter jejuni (13 pathogenic + 1 non-pathogenic) and two animal isolates were studied for the production of a toxin immunologically related to the heat-labile enterotoxin (LT) produced by a strain of Escherichia coli of human (H) origin using an immuno-dot-blot assay with immunoaffinity purified antibodies against H-LT. Polymyxin-B sulfate extracts of 72 hrs growth in eight of the 15 pathogenic strains were positive in immuno-dot-blot. Six of these positive extracts also exhibited delayed permeability factor activity in rabbit skin.

Animals↗

PubMed1990

Outbreak of Salmonella worthington meningitis & septicaemia in a hospital at Chandigarh (north India).

During August 1988 an outbreak of hospital acquired infection due to S. worthington has been reported at the Nehru Hospital, Postgraduate Institute of Medical Education and Research, Chandigarh. A total of seven neonates presented with the clinical features of meningitis and septicaemia during this outbreak and six babies died. S. worthington was isolated from blood and cerebrospinal fluid respectively. The same strains were isolated from the baby warmer mattress, baby cot, suction machine bottle and wall of the fridge. Samples from doctors, nurses and apparently healthy babies born during this period did not grow the above organism. This appears to be the first report on S. worthington in human beings from India. The outbreak was controlled by thorough cleaning and fumigation. The organisms were also mostly sensitive to antibiotics used, in contrast to the multiple drug resistant pattern reported from elsewhere.

Cross Infection↗

PubMed1987

Evaluation of immuno-dot-blot assay for detection of cholera-related enterotoxin antigen in Salmonella typhimurium.

Twenty-five strains of Salmonella typhimurium isolated in India were examined for the presence of cholera/coli-related enterotoxin antigen by a previously described latex particle agglutination test and by a newly developed immuno-dot-blot test using immunopurified goat antibody against the cholera-related enterotoxin isolated from an Escherichia coli strain of human origin. The immuno-dot-blot assay could detect 0.02 ng of purified enterotoxin. The amount of toxin antigen detected varied widely from strain to strain. Fourteen of the 25 polymyxin B-treated extracts of bacteria harvested from 6-h Casamino Acids-yeast extract broth cultures gave positive results in both serologic assays as well as in rabbit skin tests for delayed permeability factor. An additional strain was positive only in the immuno-dot-blot. Five of six stool isolates and six of seven blood isolates tested gave positive reactions. Two isolates of Salmonella enteritidis tested were also positive. The immuno-dot-blot test appears to be a simple, rapid, and reliable method for detection of cholera-related enterotoxin antigen in S. typhimurium. The demonstration of a cholera-related enterotoxin, even in small amounts, in a facultative intracellular pathogen raises interesting questions regarding its potential role in pathogenesis both of diarrheal disease and systemic infections caused by salmonellae.

Animals↗

PubMed1987

Incidence of shigellosis and multi-drug resistant Shigellae: a 10 year study.

Between 1976 and 1985 a total of 12,709 faecal samples were cultured. From these samples 760 strains (6.0%) of Shigellae were isolated. Shigella flexneri was the commonest isolate (55%), followed by S. dysenteriae (29.7%). A total of 15.7% of children under 5 years of age were positive for Shigellae. The rate of isolation was lower during the winter months than in the summer months. Only 25 strains (3.3%) were sensitive to all five antibiotics tested. A total of 617 (81.2%) were resistant to three or more antibiotics (multi-drug resistant). The minimum inhibitory concentrations (MICs) of five drugs were calculated in 100 strains. Streptomycin showed an MIC of 25 micrograms ml-1 or less for only seven strains. MICs of chloramphenicol tetracycline and ampicillin were found to be as high as 100-1000 micrograms ml-1 for the majority of strains. Sulphonamide showed an MIC of 1000 micrograms ml-1 for 93 strains.

Anti-Bacterial Agents↗

PubMed1986