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Biomedical subjects

S C Pal

Publications and source records attributed to S C Pal.

At least 55 records · Page 3Linked to original sources
PubMed1991

Serovars of multi-antibiotic resistant Escherichia coli from the freshwater environs of Calcutta, India.

For a period of one year (March 1987 to February 1988), the incidence of Escherichia coli was determined in water, sediment and plankton collected from two sampling sites in a freshwater lake extensively used by humans and animals. Densities of E. coli associated with plankton was the lowest while sediments, especially at site 2, harbored high densities of the organism. Correlation coefficients revealed that the density of E. coli in water samples was linearly correlated to temperature, pH of water, sediment and humidity. Stepwise multiple regression analysis, however, showed that sediment temperature was the dominant variable which could explain 27% of the observed variation in the numbers of E. coli in the overlying waters (p = less than 0.001). Of the 150 environmental E. coli strains which were characterized, 31 (20.7%) were found to belong to the classic enteropathogenic E. coli (EPEC) serogroups. Seven of the serogroups among the environmental EPEC strains were also encountered from EPEC strains isolated from human cases during a concurrent clinical study. None of the 150 environmental strains were enterotoxigenic or enteroinvasive but 4 strains possessed HEp-2 cell adhesive factor. With the exception of one, all the EPEC strains isolated were multi-drug resistant. From this study, it was evident that the lake is an important source of infection of EPEC and other related diarrheagenic E. coli.

Diarrhea, Infantile↗
PubMed1991

Polymerase chain reaction for detection of the cholera enterotoxin operon of Vibrio cholerae.

We report a set of oligonucleotide primers and amplification conditions for the polymerase chain reaction to detect the ctx operon of Vibrio cholerae. The results of this assay on strains of V. cholerae and related organisms were identical with those obtained by the DNA colony hybridization test with the polynucleotide probe. The detection limit of this system was 1 pg of chromosomal DNA or broth culture containing three viable cells. The polymerase chain reaction method could directly detect the ctx operon sequences in rice-water stool samples from patients with cholera.

Base Sequence↗
PubMed1991

Prospective hospital based study on persistent diarrhoea.

A total of 383 children aged less than 5 years suffering from acute watery diarrhoea or dysentery were studied in hospital to determine the rate of persistent diarrhoea. Altogether 335 (87.5%) recovered within 13 days. Only in 48 (12.5%) did the diarrhoea continue for 14 days or more, and they were considered as having persistent diarrhoea. Children aged between 7 and 18 months had a significantly increased incidence of persistent diarrhoea. Children suffering from grade II-IV malnutrition constituted the majority (70.8%) of those with persistent diarrhoea. Higher rates of isolation of Shigella flexneri, Shigella dysenteriae 1, and Salmonella typhimurium were observed among patients with persistent diarrhoea than in those with diarrhoea of shorter duration. No positive correlations were observed between the clinical severity of disease at hospital admission and measles. Breast fed babies were not prone to persistent diarrhoea.

Acute Disease↗
PubMed1991

Randomized clinical trial of norfloxacin for shigellosis.

In a randomized clinical trial, norfloxacin was compared with nalidixic acid in the treatment of acute invasive diarrhea, with particular reference to shigellosis in adults. Of 104 patients studied, 40 were positive for Shigella in stool cultures, of which 22 received norfloxacin and 18 received nalidixic acid. The patients in these two groups were comparable on admission. In the treatment of culture-positive shigellosis cases, the responses to therapy with both drugs were similar, except that the duration of fever, anorexia, and abdominal pain were less in those who received norfloxacin. Norfloxacin appeared to be superior to nalidixic acid in the treatment of shigellosis cases caused by Shigella strains resistant to nalidixic acid.

Adult↗
PubMed1991

An operational study on implementation of oral rehydration therapy in a rural community of West Bengal, India.

An operational study of a 3-tier strategy for implementation of oral rehydration therapy (ORT) was conducted in a block of West Bengal with 216,825 population through the existing health services facilities. All the grassroot level, health workers including their supervisors at various levels were trained regarding the management of patients of diarrhoea with mild to moderate degree of dehydration, by ORT. Another block in the same district with similar demographic features where this intervention was not provided served as control. After 22 months of observation, it was evident that despite adequate training, the performance of Community Health Guides (CHGs) and Anganwadi Workers (AWWs) was not encouraging because of the low utilization of both home available fluids (32.0%) and oral rehydration solution (18.0%) in the study area. Similarly, diarrhoea associated mortality could not be reduced significantly. Lack of motivation and failure to maintain sustained level of skill by the CHGs and AWWs constitute the major bottlenecks for the successful implementation of the programme at the community level.

Child, Preschool↗
PubMed1991

Clinical manifestation of Clostridium difficile enteritis in Calcutta.

233 cases with acute diarrhoea investigated, Clostridium difficile was isolated as a sole pathogen from 17 (7.3%) cases. The Major clinical features of these cases were watery diarrhoea (82.4%), bloody stool (17.6%), vomiting (64.8%), fever (17.6%) and abdominal pain (2.5%). Fourteen (82.4%) of 17 C difficile isolates were found to produce cytotoxin as detected by Verocell assay.

Child↗
PubMed1991

Simplified method for the detection of DNA hydrolysis by enteric campylobacters.

A simplified medium was developed for the detection of DNase produced by enteric campylobacters. Sensitivity and reproducibility of the test were similar to that of the improved toluidine blue DNA agar method. Logistically, the simplified DNA hydrolysis test was cheaper (5.5 times) than the earlier medium. Based on this study we recommend the routine use of the simplified medium to perform the DNase test for biotyping enteric campylobacters.

Campylobacter↗
PubMed1991

Oral rehydration solution containing 90 millimol sodium is safe and useful in treating diarrhoea in severely malnourished children.

The safety and efficacy of standard oral glucose-electrolyte solution, containing 90 mmol of sodium per litre, was evaluated in the treatment of dehydrating diarrhoea among severely malnourished (marasmic) children. A total of 81 male children aged between 6 and 48 months were studied; 41 were in the malnourished group (study group: less than 60% of Harvard Standard weight-for-age) and 40 were in the well-nourished group (control group: 80% or more Harvard Standard weight-for-age). Children of both groups could be rehydrated with standard oral rehydration solution (ORS) without encountering any clinical or biochemical complications. The results of this study lend support to the World Health Organization's concept of a unified formula of ORS for the treatment of all cases of acute diarrhoea, including severely malnourished children.

Child, Preschool↗
PubMed1991

Blood group and shigellosis.

A study on the distribution of ABO blood groups was carried out on 85 patients with clinically and bacteriologically proven shigellosis. A significant association (P less than 0.01) of blood group B was observed with shigellosis cases in comparison to controls from whom no Shigella species or other enteropathogen could be isolated. Patients with isoagglutinin B or those who possess blood group B antigen may be at a relatively increased risk of shigellosis.

ABO Blood-Group System↗
PubMed1991

Comparison of selective medium supplemented with blood & a charcoal-based blood-free medium for primary isolation of campylobacters from human faeces.

A recently developed charcoal-based, blood-free selective medium-charcoal cefoperazone deoxycholate agar (CCDA) was compared with the conventional Butzler's agar (BA) for primary isolation of enteric campylobacters from human stool specimens. CCDA yielded higher percentage (93.6%) of positive isolations as compared to BA (76.6%). The rate of isolation on CCDA was significantly higher (P less than 0.0001) than on BA. Cost-wise also, the CCDA medium was two times cheaper than BA. In addition to Campylobacter jejuni and C. coli, CCDA permitted the recovery of a recently described catalase-negative campylobacters which did not grow on BA. Based on these results the routine use of CCDA is recommended, particularly in developing countries, as blood is not required for this medium.

Blood↗
PubMed1990

Double-blind, randomized, controlled clinical trial of norfloxacin for cholera.

In a double-blind, randomized clinical trial with 78 adults with acute watery diarrhea and severe dehydration, 37 subjects were positive for Vibrio cholerae. In conjunction with rehydration therapy, 13 patients received norfloxacin, 12 received trimethoprim-sulfamethoxazole (TMP-SMX), and 12 received a placebo. Norfloxacin was superior to TMP-SMX and to the placebo in reducing stool output, duration of diarrhea, fluid requirements, and vibrio excretion. TMP-SMX was no better than the placebo.

Adult↗
PubMed1990

Purification and characterization of a novel hemagglutinin from Vibrio cholerae.

A lectin with strong hemagglutinating activity toward erythrocytes of several animal species was isolated from an 18-h culture supernatant of a diarrheagenic strain, V2, of non-O1 Vibrio cholerae. The hemagglutinin (HA) was purified free of lipopolysaccharide by salt fractionation followed by gel filtration, hydrophobic interaction chromatography, and, finally, gel filtration in the presence of urea and deoxycholate. The purification procedure resulted in an HA preparation with 80-fold enhancement of specific activity. The HA consisted of noncovalently bound subunits of Mr 62,000 and behaved essentially as a single component with pI 6.0. Nonpolar and acidic amino acids contributed 46 and 24%, respectively, to the total amino acid residues. Electron micrographs of the HA showed it to consist of large, nonstoichiometric aggregates' of disklike molecules of 10-nm diameter. Inhibition of the HA by the glycoproteins fetuin, asialofetuin, and mucin, but not by ovalbumin and simple sugars, suggested the specific requirement of complex carbohydrates for binding. Rabbit antisera to the purified HA inhibited the hemagglutinating activities of the crude cell-free HA preparations, but not cell-associated HA activities of the parent (V2) or of other O1 and non-O1 V. cholerae strains. This suggested that the released and cell-associated HA activities were mediated by antigenically distinct components. Immunoblotting experiments showed that the antisera recognized a polypeptide component of Mr 62,000 in the cell envelope preparations of the parent and several other V. cholerae O1 and non-O1 strains. These data suggested that the HA was a nonfimbrial lectin of somatic origin with no protease activity and was apparently distinct from V. cholerae HAs described so far.

Amino Acids↗
PubMed1990

Phage typing of Vibrio cholerae 01 biotype ElT or strains.

Data accumulated over the past 20 yr (1969-88) on the phage typing of V. cholerae 01 biotype ElT or strains received at the Vibrio Phage Reference Laboratory, were retrospectively analysed to ascertain the frequency of occurrence of the different phage types of Basu and Mukerjee typing scheme. The analysis revealed that phage types 2 and 4 were the most common types not only at the time when the Basu and Mukerjee typing scheme (of 1968) was introduced but also at present. The existing phage typing scheme needs to be improved with the addition of more new phages to obtain more type distinction and better discrimination within biotype ElT or strains for epidemiological studies.

Bacterial Typing Techniques↗
PubMed1989

Growth of Aeromonas spp. on Butzler Campylobacter selective agar and evaluation of the agar for the primary isolation of Aeromonas spp. from clinical specimens.

The fortuitous finding that Aeromonas spp. grew well on Butzler Campylobacter selective medium (BCSA) in a microaerobic atmosphere at 42 degrees C prompted us to evaluate the performance of BCSA for selective isolation of aeromonads in comparison with ampicillin (30 micrograms/ml) sheep blood agar (ASBA30). Overall recovery rates of aeromonads from 563 stool samples from patients with acute diarrhea were higher on ASBA30 (70.4%) than on BCSA (56.3%); however, 21 (29.5%) grew only on BCSA. The three human-associated Aeromonas spp. could be recovered on BCSA and ASBA30. We recommend the use of BCSA to laboratories reluctant to include a specific selective medium for aeromonads.

Aeromonas↗