Journal of diarrhoeal diseases research最新文献

In August 1993, an outbreak of group C rotavirus-associated gastroenteritis occurred among children attending a day-care centre in Belém, Brazil. Of the 64 children, 21 (33%) became ill. Group C rotavirus was identified in faecal specimens from 8 (38%) children with diarrhoea by electron microscopy (EM) and an enzyme immunoassay (EIA), using antibodies specific to the Cowden strain of porcine group C rotavirus. By polyacrylamide gel electrophoresis (PAGE), a pattern similar to that of group C rotavirus was observed in 5 (62.5%) of the 8 EM- and EIA-positive samples. These 5 faecal samples were confirmed to be positive for group C rotavirus by reverse transcriptase-polymerase chain reaction, using specific VP6 and VP7 primers. This is the first report of an outbreak of diarrhoea in North Brazil associated with group C rotavirus. These findings suggest that group C rotavirus may be an important aetiological agent of diarrhoea in this region, which requires further study.

The study was carried out to detect group- and subgroup-specific antigens of bovine rotaviruses. Stool specimens, collected from diarrhoeic calves of the Savar Dairy Farm, Bangladesh, were examined by an enzyme-linked immunosorbent assay, using group- and subgroup-specific monoclonal antibodies. Thirty-three specimens showed specificity for group A rotavirus. While subgrouping, 21 group A-positive specimens showed subgroup I specificity. Twelve specimens did not react with either of the subgroup I- and subgroup II-specific monoclonal antibodies.

During September 1992-August 1993, stool samples from 157 children with diarrhoea and 157 matched healthy controls were examined for the presence of Aeromonas and other enteropathogens. Aeromonas strains were tested for haemolytic activity, haemagglutination patterns, and antibiotic susceptibility. In total, 62 Aeromonas were isolated, of which 27 (17.2%) were from children with diarrhoea and 35 (22.3%) from healthy controls. Only 23 (14.6%) of the diarrhoeal children and 28 (17.8%) of the healthy controls were positive for Aeromonas; of which, 4 (2.5%) of the diarrhoeal children and 6 (3.8%) of the healthy controls showed multiple species. Aeromonas hydrophila was isolated from 5 (3.2%) children with diarrhoea and from 9 (6.4%) controls, A. veronii bv sobria from 8 (5.1%) and 7 (4.5%), A. caviae from 13 (8.3%) and 17 (10.8%), and A. schubertii from 1 (0.6%) and 2 (1.3%) respectively. No significant difference in the haemolytic activity of Aeromonas was found between diarrhoeal and healthy children. However, a significant difference (p < 0.002) was observed in mannose-resistant haemagglutination (MRHA) by diarrhoeal isolates of Aeromonas (7/27, 26%) compared to the healthy controls (1/35, 3%). Aeromonas strains were uniformly sensitive to ciprofloxacin, gentamicin, and nalidixic acid. The results of this study suggest that A. caviae strains may be associated with diarrhoea in children and MRHA may be used as one of the virulence markers for distinguishing between Aeromonas isolated from diarrhoeal children and healthy controls or environmental isolates.

To determine the mechanism of enteropathogenicity of the newly described Escherichia species, a total of 50 clinical isolates of Escherichia spp. from diarrhoeal stools were studied. Twelve isolates (24%) were found to be E. vulneris, 6 (12%) E. fergusonii, 2 (4%) E. hermannii, and the rest 30 (60%) were E. coli. Most isolates of the new species were resistant to ampicillin, tetracycline, and co-trimoxazole, but were susceptible to cephalosporins and aminoglycosides. The representative strains of all the new species produced significant fluid accumulation in the rat ileal loops both by live cells and their culture filtrates. E. vulneris, isolated from stools, showed maximum fluid accumulation. Thus, it can be inferred that these species are diarrhoeagenic, but their roles on extra-intestinal infections remain to be determined.

A hospital-based unmatched case-control study (387 cases and 387 controls) was carried out at the Government Medical College Hospital, Nagpur, India, to devise and validate a risk-scoring system for predicting the development of moderate or severe dehydration in children, aged less than five years, with acute watery diarrhoea. On unconditional multiple logistic regression, 12 risk factors--infancy, minority religion, undernutrition, not washing hands by mother before preparation of food, frequency of stools > 8/day, frequency of vomiting > 2/day, measles in previous 6 months, withdrawal of breast-feeding/other feedings, withdrawal of fluids during diarrhoea, not giving oral rehydration solutions (ORS), home available fluids and both during diarrhoea--were significant. Based on regression coefficients, these factors were ascribed statistical weights of 5, 5, 4, 4, 22, 9, 11, 13, 5, 5, 5, and 7 respectively. The receiver-operating characteristic curve suggested a total score of 48 to be the best cut-off for predicting the development of moderate or severe dehydration. At this cut-off, the sensitivity, specificity, positive predictive value, Cohen's kappa, and overall predictive accuracy were 0.81, 0.81, 0.81, 0.61, and 0.86 respectively. If substantiated by further validation, this system can be used for predicting the development of dehydration at the earlier stage, thereby reducing the mortality associated with life-threatening dehydration.

The study examines the age-related differences in the density of Escherichia coli heat-stable enterotoxin (STa) receptors in the small intestine of rabbits. The number of STa receptors was found to be 1.7 x 10(12) in 14-day old rabbits compared to 2.4 x 10(9) in 14-week old rabbits per milligram brush-border membrane protein. The STa-induced guanylyl cyclase activity in the intestinal brush-border membranes was found to be stimulated by 6.2 folds over the basal enzyme activity in 14-day old rabbits, whereas in the 14-week old rabbits, it was 4 folds over the basal activity. Moreover, the enzyme activity remained lower in the adult rabbits compared to the younger ones. Autoradiographic analysis of sodium dodecyl sulphate polyacrylamide gel electrophoresis showed two STa-binding proteins of apparent molecular weights of 140 and 38 kDa in the intestinal brush-border membranes of rabbits.

Six isolates of Aeromonas eucrenophila--2 from water and 4 from superficial skin ulcer of cat fish--were examined for haemagglutination, serum sensitivity, chitinase production and enterotoxicity, and correlation, if any, between them; only one strain showed haemagglutination and was inhibited by both D-mannose and L-fucose. All the strains showed resistance to normal human serum, but produced chitinase; one of them elaborated inducible chitinase. All these strains caused fluid accumulation only after 1-4 serial passages through rabbit ileal loops, of which one strain that elaborated inducible chitinase caused significantly more (p < 0.005) fluid accumulation. These observations indicate that there is no correlation between enterotoxicity and haemagglutination and/or serum resistance, and these properties did not change after animal passage. However, a correlation could be observed between elaboration of inducible chitinase and enterotoxin production.