International Centre for Diarrhoeal Disease Research, Bangladesh

About: International Centre for Diarrhoeal Disease Research, Bangladesh is a facility organization based out in Dhaka, Bangladesh. It is known for research contribution in the topics: Population & Vibrio cholerae. The organization has 3103 authors who have published 5238 publications receiving 226880 citations. The organization is also known as: SEATO Cholera Research Laboratory & Bangladesh International Centre for Diarrhoeal Disease Research.

Broad up-regulation of innate defense factors during acute cholera.

Abstract: We used a whole-genome microarray screening system (Affymetrix human GeneChips covering 47,000 different transcripts) to examine the gene expression in duodenal mucosa during acute cholera. Biopsies were taken from the duodenal mucosa of seven cholera patients 2 and 30 days after the onset of diarrhea, and the gene expression patterns in the acute- and convalescent-phase samples were compared pairwise. Of about 21,000 transcripts expressed in the intestinal epithelium, 29 were defined as transcripts that were up-regulated and 33 were defined as transcripts that were down-regulated during acute cholera. The majority of the up-regulated genes characterized were found to have an established or possible role in the innate defense against infections; these genes included the LPLUNC1, LF, VCC1, TCN1, CD55, SERPINA3, MMP1, MMP3, IL1B, LCN2, SOCS3, GDF15, SLPI, CXCL13, and MUC1 genes. The results of confirmative PCR correlated well with the microarray data. An immunohistochemical analysis revealed increased expression of lactoferrin in lamina propria cells and increased expression of CD55 in epithelial cells, whereas increased expression of the SERPINA3 protein (α1-antichymotrypsin) was detected in both lamina propria and epithelial cells during acute cholera. The expression pattern of CD55 and SERPINA3 in cholera toxin (CT)-stimulated Caco-2 cells was the same as the pattern found in the intestinal mucosa during acute cholera, indicating that the activation of the CD55 and SERPINA3 genes in intestinal epithelium was induced by CT. In conclusion, during acute cholera infection, innate defense mechanisms are switched on to an extent not described previously. Both direct effects of CT on the epithelial cells and changes in the lamina propria cells contribute to this up-regulation.

Entamoeba moshkovskii Is Associated With Diarrhea in Infants and Causes Diarrhea and Colitis in Mice

Abstract: Entamoeba histolytica causes extensive mortality and morbidity worldwide through diarrheal disease and abscess formation in parenchymal tissues such as liver, lung, and brain. In contrast, other amoebae that infect humans include Entamoeba dispar, Entamoeba moshkovskii, Entamoeba coli, Entamoeba hartmanni, and Endolimax nana, which have been considered nonpathogenic commensals of the human gut [1–3]. Dientamoeba fragilis and Entamoeba polecki have been associated with diarrhea and Entamoeba gingivalis with periodontal disease [4, 5]. E. moshkovskii is genetically related to E. histolytica and E. dispar and is microscopically indistinguishable from them in its cyst and trophozoite forms [6]. This species of Entamoeba was first identified in sewage in Moscow by Tshalaria in 1941 [7] and was initially thought to be a free-living common protozoan species in anoxic sediments and in environments such as brackish coastal pools. The first human isolate was obtained from a resident of Laredo, Texas, who suffered from diarrhea, weight loss, and epigastric pain in 1961 [8]. This finding would seem to suggest and/or support that E. moshkovskii can be pathogenic. At first, this isolate was named E. histolytica Laredo strain and shared biological features with E. moshkovskii. Both the Laredo strain and E. moshkovskii grow at room temperature and were resistant to osmotic shock and to drugs used in the chemotherapy of amoebiasis such as emetine [9]. Subsequent molecular studies revealed that E. histolytica Laredo is identical with E. moshkovskii [10]. E. moshkovskii is a common Entamoeba infection in humans in some settings. It is composed of anywhere from as little as 1% to as high as 50% of the E. histolytica/E. dispar/E. moshkovskii complex parasites detected in fecal samples in limited studies from Australia, Bangladesh, India, Iran, Tanzania, and Turkey [6, 11–16]. These studies for the most part tested stool samples submitted to clinical microbiology laboratories from patients with gastrointestinal symptoms, suggesting that E. moshkovskii could cause disease. However, in HIV-1–infected individuals in northern Tanzania, E. moshkovskii was not associated with enteric symptoms nor immune status [17]. Thus, the ability of E. moshkovskii to cause disease in humans remains unclear. Here we tested the ability of E. moshkovskii to cause colitis and diarrhea in a murine model system, in which intracaecal inoculation with E. histolytica trophozoites into CBA/J, C3H/HeN, and C3H/HeJ mice leads to amebic colitis [18–20]. In addition, we tested in a longitudinal study of children in Bangladesh not only if E. moshkovskii was present in stool samples from infants with diarrhea, but whether the E. moshkovskii infection was newly acquired at the time of the diarrheal illness.

Detection of Campylobacter in Stool and Determination of Significance by Culture, Enzyme Immunoassay, and PCR in Developing Countries

Abstract: Campylobacter is a common bacterial enteropathogen that can be detected in stool by culture, enzyme immunoassay (EIA), or PCR. We compared culture for C. jejuni/C. coli, EIA (ProSpecT), and duplex PCR to distinguish Campylobacter jejuni/C. coli and non-jejuni/coli Campylobacter on 432 diarrheal and matched control stool samples from infants in a multisite longitudinal study of enteric infections in Tanzania, Bangladesh, and Peru. The sensitivity and specificity of culture were 8.5% and 97.6%, respectively, compared with the results of EIA and 8.7% and 98.0%, respectively, compared with the results of PCR for C. jejuni/C. coli. Most (71.6%) EIA-positive samples were positive by PCR for C. jejuni/C. coli, but 27.6% were positive for non-jejuni/coli Campylobacter species. Sequencing of 16S rRNA from 53 of these non-jejuni/coli Campylobacter samples showed that it most closely matched the 16S rRNA of C. hyointestinalis subsp. lawsonii (56%), C. troglodytis (33%), C. upsaliensis (7.7%), and C. jejuni/C. coli (2.6%). Campylobacter-negative stool spiked with each of the above-mentioned Campylobacter species revealed reactivity with EIA. PCR detection of Campylobacter species was strongly associated with diarrhea in Peru (odds ratio [OR] = 3.66, P < 0.001) but not in Tanzania (OR = 1.56, P = 0.24) or Bangladesh (OR = 1.13, P = 0.75). According to PCR, Campylobacter jejuni/C. coli infections represented less than half of all infections with Campylobacter species. In sum, in infants in developing country settings, the ProSpecT EIA and PCR for Campylobacter reveal extremely high rates of positivity. We propose the use of PCR because it retains high sensitivity, can ascertain burden, and can distinguish between Campylobacter infections at the species level.

Polymerase Chain Reaction (PCR): A Short Review

Abstract: Diagnosis of disease now a days is mostly laboratory dependent. Due to recent advances in medical science and molecular biology, most of the diagnosis of uncommon, complicated, unusual presentation of disease has left the option of molecular diagnosis as the number one diagnostic modalities. Many molecular techniques are now being widely used throughout the world including PCR, flow cytometry, tissue microarray, different blots, and genetic diagnosis. Among these PCR is the most widely accepted, commonly used diagnostic modalities with very high specificity and sensitivity for correct diagnosis. We have reviewed the principle, application, advantages and disadvantages of PCR in laboratory diagnosis of disease. DOI: http://dx.doi.org/10.3329/akmmcj.v4i1.13682 AKMMC J 2013: 4(1): 30-36