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Biomedical subjects

I Huq

Publications and source records attributed to I Huq.

At least 37 records · Page 2Linked to original sources
PubMed1983

Changes in serotypes of enterotoxigenic Escherichia coli in Dhaka over time: usefulness of polyvalent antisera.

The finding that enterotoxigenic (ET) Escherichia coli strains from many geographic areas belong to a limited number of serogroups led investigators to hope that polyvalent antisera could be used to screen for ET E. coli in areas of the world where more complicated tests of toxigenicity are not available. We compared the serotypes of 207 ET E. coli strains obtained from patients attending the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh, in 1980 with results obtained from similar surveys conducted in 1976 and 1978. During that time the distribution of serogroups changed significantly so that only 46% of our strains had O serogroups included in the polyvalent antisera capable of detecting 66% of ET E. coli strains in 1978. O167, a serogroup which was not included previously, was the third most common serogroup in our study. These findings suggest that polyvalent antisera used to screen for ET E. coli need to be reassessed over time as well as in different geographic areas and may not be as useful for field diagnosis as was originally hoped.

Diarrhea↗
PubMed1982

Longitudinal studies of infectious diseases and physical growth of children in rural Bangladesh. II. Incidence of diarrhea and association with known pathogens.

Longitudinal studies were done in two villages rural Bangladesh to learn more about the interactions between infectious diseases and the nutritional status of children. Diarrheal diseases, identified by surveillance of 197 children aged 2-60 months, were studied for bacterial, viral and parasitic enteropathogens in 1978-1979. The annual incidence of diarrhea was highest in children aged 2-11 months, and declined progressively with age from seven to four episodes per child per year. An enteropathogen was identified from rectal cultures taken during diarrhea in 51% of episodes and from 6% of monthly cultures taken when diarrhea was not present. Enterotoxigenic Escherichia coli were the pathogens found most frequently, followed by shigellae and rotaviruses. Diarrheal episodes associated with shigellae had the longest duration, while episodes associated with Vibrio cholerae or with rotavirus were more frequently associated with dehydration. E. coli diarrhea had a peak incidence during the hot months, and shigellosis was more frequent during the cool, dry months.

Bangladesh↗
PubMed1981

Incidence and severity of rotavirus and Escherichia coli diarrhoea in rural Bangladesh. Implications for vaccine development.

In a 1 year study of diarrhoea in a village in rural Bangladesh, enterotoxigenic Escherichia coli (ETEC) were the most frequently detected enteropathogens; shigellae were the second most commonly detected enteropathogens and rotaviruses the third. ETEC and rotavirus were found in 31% of diarrhoea episodes experienced by children aged less than 2 years and in 70% of episodes associated with dehydration. Furthermore these two pathogens were identified in the stools of 77% of young children with life-threatening dehydration seen at a diarrhoea treatment centre. The association of ETEC and rotavirus with such a substantial proportion of cases of dehydrating diarrhoea suggests that immunoprophylaxis to reduce the high incidence of deaths from diarrhoea in developing countries may be feasible and that vaccine development should concentrate on these two enteropathogens.

Bangladesh↗
PubMed1980

Binding of intraluminal toxin in cholera: trial of GM1 ganglioside charcoal.

A study was undertaken to investigate whether toxin produced in the gut lumen contributes significantly to clinical illness and whether binding such toxin by GM1 ganglioside adsorbed onto charcoal could alter the clinical course of disease. 46 patients with severe cholera receiving standard intravenous therapy were randomly assigned to one of three groups: GM1 ganglioside-charcoal (16), charcoal alone (16), or water (14). The results demonstrated that patients were given sufficient GM1 ganglioside-charcoal to bind all luminal toxin produced by Vibrio cholerae in their intestines. Patients treated with GM1 ganglioside tended to have a greater reduction in purging than patients treated with either charcoal alone or water. This difference was statistically significant soon after beginning medication (8-15 h) and the reduction in fluid-loss was especially pronounced in patients with very severe initial purging who had been ill only for a short time before admission. These results suggest that toxin produced in the gut lumen increases fluid-loss early in cholera, but that later in the course of disease, toxin which is inaccessible to luminal binding agents in the major stimulus of purging.

Adolescent↗
PubMed1980

Use of antisera for identification of enterotoxigenic Escherichia coli.

The usual methods for identifying enterotoxigenic Escherichia coli (ETEC) strains involve testing for production of heat-labile enterotoxins. To simplify the identification of ETEC, antisera against common ETEC O serogropus were used to identify ETEC in the stools from 618 patients with acute diarrhoea and dehydration (greater than or equal to 5% loss of body-weight) receiving treatment at a hospital in Dacca, Bangladesh. Compared with enterotoxin testing the antisera had a sensitivity of 64%, a specificity of 96%, and a predictive accuracy of 89%. These antisera may be useful in the identification ETEC in clinical laboratories which are unable to perform toxin testing and should be evaluated in other geographical areas.

Dehydration↗
PubMed1980

Disease due to enterotoxigenic Escherichia coli in Bangladeshi adults: clinical aspects and a controlled trial of tetracycline.

The clinical characteristics of disease due to enterotoxigenic Escherichia coli (ETEC) were determined in 88 adult males admitted to a hospital in Dacca, Bangladesh, with moderate to severe dehydration. Persons infected with ETEC strains producing both heat-labile toxin (LT) and heat-stable (ST) toxin had more dehydration and acidosis, longer duration of illness, and greater stool volume than persons infected with strains producing only ST. Tetracycline therapy, evaluated in 63 cases, resulted in slightly earlier termination of illness in patients with LT-ST strains but had no effect on illness in the patients with ST strains. In both groups of patients tetracycline shortened the duration of excretion of organisms. Because of its limited effectiveness and the generally excellent response of ETEC diarrhea to rehydration therapy alone, tetracycline is not warranted for use in treatment of ETEC diarrhea in adults in this population.

Adult↗
PubMed1980

A two-year study of bacterial, viral, and parasitic agents associated with diarrhea in rural Bangladesh.

Enteric pathogens associated with diarrhea were studied for two years at a diarrhea treatment center in rural Bangladesh. Enterotoxigenic Escherichia coli (ETEC) was the most frequently identified pathogen for patients of all ages. Rotavirus and ETEC were isolated from approximately 50% and approximately 25%, respectively, of patients less than two years of age. A bacterial or viral pathogen was identified for 70% of these young children and for 56% of all patients with diarrhea. Most ETEC isolates were obtained in the hot dry months of March and April and the hot wet months of August and September. Rotavirus identification peaked in the cool dry months of December and January, but infected patients were found year-round. The low case-fatality rates for patients with watery diarrhea and substantial dehydration further document the usefulness of treating patients with diarrhea with either a glucose- or sucrose-base electrolyte solution such as those used in this treatment center.

Age Factors↗
PubMed1980

Detection of enterotoxigenic Escherichia coli by DNA colony hybridization.

A method fo detecting large numbers of isolates of enterotoxigenic Escherichia coli is described in which the genes encoding th enterotoxins are detected, rather than the toxins themselves. Radiolabeled fragments of DNA encoding the heat-labile (LT) or heat-stable (ST) toxins were used as hybridization probes for homologous DNA sequences in E. coli colonies grown and lysed in situ on nitrocellulose filters. The LT probe detected all of 31 E. coli strains producing ST and LT or only LT, while the ST probe detected 12 of 17 strains producing only ST and three of 26 strains producing ST and LT. These results suggest that the LTs produced by different isolates of E. coli are homologous and that human isolates of E. coli produce at least two heterologous STs detectable in the infant mouse assay. The hybridization method also detected the presence of enterotoxigenic E. coli in bacterial growth in directly spotted stools from patients with acute diarrhea.

Acute Disease↗
PubMed1980

Emergence of multiply antibiotic-resistant Vibrio cholerae in Bangladesh.

In December 1979, a Vibrio cholerae O1 resistant to tetracycline, ampicillin, kanamycin, streptomycin, and trimethoprim-sulfamethoxazole was obtained from a patient with cholera at the Matlab Hospital, Bangladesh. All 256 isolates of V. cholerae O1 stocked in the previous six months were tested for antibiotic sensitivity: 54 were resistant to tetracycline, and 44 of these were resistant to all five antibiotics. The clinical presentation and hospital course for 51 patients with resistant strains of V. cholerae O1 and 102 patients with sensitive strains were compared by their medical records. Patients with resistant strains were indistinguishable from controls by age, sex, or severity of symptoms at presentation. All were treated with tetracycline, and patients with the resistant strains purged longer (mean, 37 vs. 25 hr; P less than 0.01) and in greater volume (mean 4.3 vs. 2.3 liters; P less than 0.01) and their controls with cholera due to susceptible strains. A resistance plasmid was identified. Based on these results, antibiotic use in the areas with resistant vibrios must be reconsidered.

Anti-Bacterial Agents↗
PubMed1980

Isolation of drug-resistant Aeromonas hydrophila from aquatic environments.

Antibiotic-resistant strains of Aeromonas hydrophila have been isolated from the natural environment in the Chesapeake Bay and areas surrounding Dacca and the Matlab region of Bangladesh. The Bangladesh strains carried resistance to chloramphenicol, streptomycin, and tetracycline, and 57% of them had a multiple streptomycin-tetracycline resistance phenotype correlated with the presence of a large plasmid. The Chesapeake Bay strains were resistant to polymyxin B ane tetracycline, but showed neither multiple resistance nor R-factor carriage. Twenty-five percent of the environmental strains were toxigenic in a Y-1 adrenal cell assay. Toxigenicity showed no positive correlation with drug resistance or with plasmid carriage. Environmental areas of heavy human impact appear to be associated with a higher incidence of antibiotic-resistant strains of aeromonads.

Aeromonas↗
PubMed1980

Detection of Escherichia coli enterotoxins in stools.

We determined whether enterotoxigenic Escherichia coli diarrhea could be diagnosed by direct examination of stools for heat-labile (LT) and heat-stable (ST) enterotoxins. The Y-1 adrenal cell and an enzyme-linked immunosorbent assay (ELISA) detected LT in 85 and 93%, respectively, of stool specimens obtained from adults with acute diarrhea from whom an LT- and ST-producing organism had been isolated. Furthermore, the ELISA assay detected LT in 8 of 35 stool specimens from which no LT-producing E. coli had been isolated. The infant mouse assay was utilized to detect ST in these stool specimens and was found to be an insensitive method, showing positive results in only 36% of the specimens from which an ST-producing organism was isolated. Further studies are warranted to determine the diagnostic value of direct detection of LT in stools, especially by the ELISA method.

Adolescent↗
PubMed1979

Relationship between enterotoxin production and serotype in enterotoxigenic Escherichia coli.

We examined the relationship between serotype and enterotoxin production in 109 enterotoxigenic Escherichia coli strains isolated from 109 patients with severe cholera-like diarrhea in Dacca, Bangladesh. Of 69 strains producing both heat-labile and heat-stable toxins, 59 (86%) belonged to the one of four O serogroups, and 56 (81%) of these strains belonged to one of six O:K:H serotypes. In contrast, 34 strains producing only heat-stable toxin were distributed among 15 O serogroups, and six strains producing only heat-labile toxin were distributed among six O serogroups. Twelve strains producing heat-labile and heat-stable toxins and five strains producing heat-stable toxin were found which had the same serotype (O78:K-:H12) and biotype. It appears that at least in one geographic setting E. coli strains producing both heat-labile and heat-stable toxins are more restricted in their O groups and O:K:H serotypes than E. coli that produce only heat-stable toxin and that certain serobiotypes may commonly include strains which produce both toxin types.

Bacterial Toxins↗
PubMed1979

Comparison of four plating media for isolating Vibrio cholerae.

Two brands of thiosulfate citrate bile salts sucrose agar and Monsur taurocholate tellurite gelatin (TTG) agar were compared with two newly developed media, sucrose tellurite teepol agar and Vibrio parahaemolyticus agar for isolation and identification of Vibrio cholerae. The thiosulfate citrate bile salts sucrose and TTG agars were the best selective media, whereas sucrose tellurite teepol agar was the poorest. Both TTG and sucrose tellurite teepol agars were good for use in follow-up serological tests, whereas only TTG agar could be used for follow-up oxidase tests. In our opinion TTG agar has more advantages for cholera research laboratories routinely culturing large numbers of patients for cholera on a daily basis and where media needs can be accurately predicted. In contrast, in smaller clinical laboratories or in laboratories investigating epidemics, thiosulfate citrate bile salts sucrose agar is best because it is commercially available and easy to prepare and can be used to distinguish colonies of suspect V. cholerae from V. parahaemolyticus.

Bangladesh↗
PubMed1979

Use of colony pools for diagnosis of enterotoxigenic Escherichia coli diarrhea.

Diagnosis of enterotoxigenic Escherichia coli diarrhea was made in 109 adult males with an acute dehydrating cholera-like syndrome in Dacca, Bangladesh, by testing 10 colonies isolated from admission stool specimens for production of heat-labile and heat-stable toxins. Toxin testing of one colony yielded a diagnosis in 92% of the cases, testing of two colonies yielded a diagnosis in 95% of the cases, testing of a pool of 5 colonies yielded a diagnosis in 95% of the cases, and testing of a pool of 10 colonies yielded a diagnosis in 96% of the cases. From stool cultures obtained on subsequent days, toxin testing of individual colonies and pools revealed diminished efficacy of pooling with decreasing numbers of enterotoxin-positive isolates in the pool. To detect the presence of enterotoxigenic E. coli in stools, toxin testing of 5 individual isolates and a pool of 10 colonies was found to be almost as effective as the testing of 10 individual isolates.

Bacteriological Techniques↗