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.

Molecular analysis of the rstR and orfU genes of the CTX prophages integrated in the small chromosomes of environmental Vibrio cholerae non-O1, non-O139 strains

Abstract: Summary The ctxAB genes encoding cholera toxin, reside in the genome of a filamentous bacteriophage CTXφ. The presence of CTX prophage in non-epidemic environmental Vibrio cholerae strains is rare. The CTX prophage, the lysogenic form of CTXφ in V. cholerae, is comprised of the ‘RS2’ and the ‘Core’. Analysis of the rstR gene present in the RS2 region of the CTX prophage revealed the presence of new alleles of the prophages in four environmental non-O1, non-O139 strains VCE22 (O36), VCE228 (O27), VCE232 (O4) and VCE233 (O27), and the CTX prophages are located in the small chromosomes. Phylogenetic analysis based on the nucleotide sequences of the rstR and orfU (present in the core) genes of these prophages placed them in a single unique cluster, which is distally located compared with that of epidemic V. cholerae O1 strains. Further analysis indicated that the genome of the prophage present in the strain VCE22 is devoid of the ctxAB genes, called pre-CTX prophage and the strain also possess the toxin-coregulated pilus protein coding gene tcpA of classical type, another important pathogenicity determining locus of the epidemic V. cholerae strains. Comparative analysis of the nucleotide sequences of the rstR and orfU genes indicated that the pre-CTX prophage of VCE22 might be the progenitor of new alleles of the CTX prophages present in these environmental strains.

Microevolution of Mycobacterium tuberculosis in a Tuberculosis Patient

Abstract: Five Mycobacterium tuberculosis isolates were obtained from three body sites from a Dutch patient. The isolates displayed a single genotype by 24-locus MIRU-VNTR typing (except for a single locus not amplified from one isolate) but were differentiated by small variations in IS6110 fingerprints, spoligotypes, 6 hypervariable MIRU-VNTR loci, and/or DiversiLab profiles, revealing patterns of microevolution in a clonal infection.

Newborn umbilical cord and skin care in Sylhet District, Bangladesh: implications for the promotion of umbilical cord cleansing with topical chlorhexidine.

Abstract: Newborn cord care practices may directly contribute to infections, which account for a large proportion of the four million annual global neonatal deaths. This formative research study assessed current umbilical and skin care knowledge and practices for neonates in Sylhet District, Bangladesh, in preparation for a cluster-randomized trial of the impact of topical chlorhexidine cord cleansing on neonatal mortality and omphalitis. Unstructured interviews (n=60), structured observations (n=20), rating and ranking exercises (n=40) and household surveys (n=400) were conducted to elicit specific behaviors regarding newborn cord and skin care practices. These included hand-washing, skin and cord care at the time of birth, persons engaged in cord care, cord cutting practices, topical applications to the cord at the time of birth, wrapping/dressing of the cord stump and use of skin-to-skin care. Overall 90% of deliveries occurred at home. The umbilical cord was almost always (98%) cut after delivery of the placenta, and cut by mothers in more than half the cases (57%). Substances were commonly (52%) applied to the stump after cord cutting; turmeric was the most common application (83%). Umbilical stump care revolved around bathing, skin massage with mustard oil and heat massage on the umbilical stump. Overall 40% of newborns were bathed on the day of birth. Mothers were the principal provider for skin and cord care during the neonatal period and 9% of them reported umbilical infections in their infants. Unhygienic cord care practices are prevalent in the study area. Efforts to promote hand-washing, cord cutting with clean instruments and avoiding unclean home applications to the cord may reduce exposure and improve neonatal outcomes. Such efforts should broadly target a range of caregivers, including mothers and other female household members.

Quorum Regulated Resistance of Vibrio cholerae against Environmental Bacteriophages.

Abstract: Predation by bacteriophages can significantly influence the population structure of bacterial communities. Vibrio cholerae the causative agent of cholera epidemics interacts with numerous phages in the aquatic ecosystem, and in the intestine of cholera patients. Seasonal epidemics of cholera reportedly collapse due to predation of the pathogen by phages. However, it is not clear how sufficient number of the bacteria survive to seed the environment in the subsequent epidemic season. We found that bacterial cell density-dependent gene expression termed "quorum sensing" which is regulated by signal molecules called autoinducers (AIs) can protect V. cholerae against predatory phages. V. cholerae mutant strains carrying inactivated AI synthase genes were significantly more susceptible to multiple phages compared to the parent bacteria. Likewise when mixed cultures of phage and bacteria were supplemented with exogenous autoinducers CAI-1 or AI-2 produced by recombinant strains carrying cloned AI synthase genes, increased survival of V. cholerae and a decrease in phage titer was observed. Mutational analyses suggested that the observed effects of autoinducers are mediated in part through the quorum sensing-dependent production of haemaglutinin protease, and partly through downregulation of phage receptors. These results have implication in developing strategies for phage mediated control of cholera.