Enterotoxigenicity screening of viable environmental Vibrio cholerae strains from rainwater pools in a university campus in Chennai, South India.

BACKGROUND: Vibrio spp., being primarily inhabitants of the aquatic environment, pose a severe health threat to humans. This problem is escalated in developing countries where water-logging after rainfall is very common. Therefore, screening of environmental water samples for the presence of clinically important species of Vibrio becomes essential. METHODS: This study was conducted for a period of 1 y. Water samples were collected every month from 4 locations where water pools formed after rains, on the campus of a university in Chennai, South India. The water samples were monitored for Vibrio species, and characterized isolates were screened for enterotoxigenicity. RESULTS: Thirty isolates of Vibrio cholerae belonging to a variety of serogroups and 11 strains of Vibrio species other than cholerae were isolated from the rainwater pools. On polymerase chain reaction (PCR) screening, while all the strains were positive for the ompW gene, none tested positive for the ctxA gene. CONCLUSIONS: Though all the environmental isolates of V. cholerae were non-epidemic, 4 isolates demonstrated enterotoxigenicity by rabbit ileal loop method and antibiotic resistance to drugs. This is of concern and underscores the importance of screening environmental specimens and improving civic infrastructure to prevent prolonged water-logging in developing countries.

Bacteriological analysis of water samples from tsunami hit coastal areas of Kanyakumari district, Tamil Nadu.

Water borne diseases such as cholera, enteric fever and dysentery were expected after the tsunami, which hit the coastal areas of Kanyakumari district, Tamil Nadu. In the present study 151 drinking water sources were collected from the tsunami affected villages and relief shelters and tested for coliforms and pathogens. Nine well water samples were also collected for specific bacteriological analysis. Presence of coliforms was detected in 56 (37%) water samples. One isolate each of Salmonella Paratyphi B and NAG Vibrio were isolated from two well water samples. There was no report of acute diarrhoeal diseases or typhoid illness during the post tsunami period monitored by a field microbiology laboratory for a month.

Antiinflammatory and antiulcer activities of Bambusa arundinacea.

The extracts of Bambusa arundinacea have been used in Indian folk medicine to treat various inflammatory conditions. The plant has got antiulcer activity also. It is thought that these two properties in the same extract are very much useful in the treatment of inflammatory conditions. It is well known fact that the most of the available antiinflammatory drugs are ulcerogenic. The antiinflammatory effect of the methanol extract of the leaves of Bambusa arundinacea against carrageenin-induced as well as immunologically induced paw oedema and also its antiulcer activity in albino rats have been studied and found to be significant when compared to the standard drugs. The combination of methanol extract and phenylbutazone (Non-Steroidal Antiinflammatory Agent, NSAIA) has been studied and found to be the most potent antiinflammatory activity experimentally with least toxic (no ulcerogenic) activity. Thus, the combination of herbal product (methanol extract of Bambusa arundinacea) with modern medicine (NSAIAs) will produce the best antiinflammatory drug and will be useful for long-term treatment of chronic inflammatory conditions like rheumatoid arthritis with peptic ulcer, which are common.

Kinetics of peripheral blood leucocyte counts in patients following thermal injuries.

Total and differential white cell counts (WCC) were done in 50 patients with burns involving 10% to 40% of the total body surface area (TBSA) and in 32 age and sex matched controls. Polymorphonuclear cell counts were low from 1st to 30th post burn (PB) days, lymphocyte counts were normal throughout the PB period whereas eosinophil counts were high from 1st to 60th PB days. Total leucocyte counts were significantly lower than controls from 8th to 60th PB days.

Kinetics of peripheral blood T cell numbers and functions in patients with burns.

Cell-mediated immunity (CMI) was assessed in 58 patients with burns involving 10% to 40% of the total body surface area (TBSA), and in 16 normal healthy individuals, by using two parameters, the total T-cell counts in peripheral circulation and T-cell function as indicated by the leukocyte migration inhibition (LMI) test. Three recall antigens from Candida albicans, S. typhi, and E. histolytica were used to elicit the LMI. T-cell function was found to be significantly depressed in burns involving more than 25% TBSA. Depression of T-cell function started after the seventh postburn (PB) day and continued until the sixtieth PB day.

Humoral and cell-mediated immune responses to leptospires in different human cases.

Humoral and cell-mediated immune responses (CMI) to leptospirosis were studied in different groups of human patients. These included clinically suspected cases of leptospirosis, patients with jaundice (HBsAg negative), cases of pyrexia of unknown origin (PUC) (Widal and blood culture negative for typhoid) and healthy blood donors. Humoral immune response was evaluated with nine live strains representing different serogroups of leptospires and CMI with lysates of four strains. The study showed that the CMI appeared earlier than the humoral response which might be useful in the early detection of the disease. As in the humoral immune response, cross reactions to different leptospires were also seen in CMI response.

A study on the usefulness of counter immuno-electrophoresis for the detection of Salmonella typhi antigen in the sera of suspected cases of enteric fever.

Counter immuno-electrophoresis (CIE) was used to detect the presence of Salmonella typhi antigen and antibodies in the sera of 123 suspected cases of enteric fever. Of these, 68 had been incompletely treated with various antibiotics before establishing the diagnosis. The sera of 31 (25%) of the 123 cases showed the presence of S. typhi antigen. Blood culture was positive for S. typhi in only one case. Antigen could be demonstrated in sera of patients with fever ranging from two to ten days. Antigen could also be demonstrated after ten days in sera of patients who had taken some antibiotics. There is no apparent relationship between the presence of antigen and antibodies in the sera, and no apparent relationship between the CIE antibody and Widal antibody titres.

Serological evidence of leptospirosis in a human population following an outbreak of the disease in cattle.

A serological study of leptospirosis in a human population, mainly children of a village near Madras City in Tamilnadu State, India, was undertaken following an outbreak of the disease in cattle as evidenced by clinical symptoms and serology. 27 (68%) of the 40 animal sera tested were positive for leptospiral antibodies. Though cross reactions were present, higher titres and a greater number of positive reactions were seen against autumnalis antigen. 35 (47%) of the 75 human sera gave positive antibody titres and, of these, 22 showed the presence of antibodies to autumnalis antigen.

Isolation of leptospires and demonstration of antibodies in human leptospirosis in Madras, India.

Among 25 clinically suspected cases of leptospirosis, organisms could be isolated from blood and urine of only 10 cases but demonstrated in 15 cases. Antibody titres at a low level were observed to one or more leptospiral antigens in all 25 cases. Nine of the repeated samples from 12 cases showed a four-fold rise in titre. The highest antibody titres were seen against autumnalis. The predominant clinical picture was of fever, myalgia, conjunctival suffusion and jaundice with renal involvement.

Detection of circulating antigen in patients with rhinosporidiosis.

A study was undertaken to demonstrate antibodies or antigen in the serum or plasma of 69 patients with rhinosporidiosis. These patients were divided into three groups, depending upon the duration of their illness. In 14 (46.7%) of 30 patients with 1-3 years of infection with R. seeberi, 18 (78.3%) of 23 patients with 4-9 years of infection and 16 (100%) of 16 patients with 10 or more years of infection, apparent rhinosporidial antigen was found in their serum or plasma by counterimmunoelectrophoresis (CIE). No antibodies could be demonstrated, by immunodiffusion (ID) or by CIE, in the serum or plasma of the 69 patients. CIE was more sensitive for the detection of precipitating antigen than ID.

Cell mediated immune response in human cases of rhinosporidiosis.

Leukocyte migration inhibition (LMI) and T lymphocyte counts were used as measures of cell mediated immunity in 37 patients with rhinosporidiosis and 18 healthy individuals. LMI was higher in all the patients than the normal controls, and it was maximal in patients with infection of 3-9 years' duration. When the chronicity of infection exceeded 10 years, there was a fall in LMI response although it was still more than that of the normal controls. The T cell count was significantly low with infection of 1-2 years' duration than in normals, but it rose to normal values in patients with infection that had lasted 3 years or more.

A study of drug resistance among Salmonella typhi and Salmonella paratyphi A in an endemic area, 1977-79.

Tests for antibiotic resistance were carried out on 198 strains of Salmonella typhi and S. paratyphi A isolated from cases of enteric fevers. Their minimal inhibitory concentrations for streptomycin, chloramphenicol, ampicillin, furazolidine and co-trimoxazole were estimated by plate dilution technique. Four strains of S. typhi and one strain of S. paratyphi A were found to show multiple resistance with a set pattern of resistance to chloramphenicol, streptomycin, sulphonamide, tetracycline and spectinomycin. All the five strains carried R-factors. Three of the resistant S. typhi belonged to Phage type 'O' and one was in Phage type 'A'. The single resistant S. paratyphi A belonged to Phage type '2'.

Relationship of macrophages to cell-mediated immunity in experimental Nocardia asteroides infection.

Marked in vivo intracellular killing of Nocardia asteroides occurred in the peritoneal macrophages obtained 72 h after an intraperitoneal challenge with N. asteroides, in guinea pigs either actively immunized with ribonucleic acid protein or passively immunized by immune spleen cell transfer from actively immunized donor guinea pigs. This specific killing of N. asteroides in immune macrophages persisted for at least up to 60 days. Administration of antimacrophage sera before intravenous challenge with N. asteroides in the immune guinea pigs produced an early death of the animals, and the total tissue counts of N. asteroides in the liver, spleen, lungs, and heart remained the same in them as in unimmunized controls.

Cell-mediated immunity to Nocardia asteroides induced by its ribonucleic acid protein fraction.

Guinea pigs immunized with ribonucleic acid protein fraction from Nocardia asteroides developed high cell-mediated immunity within 2 weeks, as shown by increased macrophage microbicidal activity and macrophage migration inhibition. This immunity protected against intravenous and subcutaneous challenge with N. asteroides and persisted for at least 70 days.