Munirul Alam, Marzia Sultana, G. Balakrish Nair, Abul K.M. Siddique et al.
Vibrio cholerae persists in aquatic environments predominantly in a nonculturable state. In this study coccoid, nonculturable V. cholerae O1 in biofilms maintained for 495 days in Mathbaria, Bangladesh, pond water became culturable upon animal passage. Culturability, biofilm formation, and the wbe, ...
R. Bradley Sack, Abdullah Siddique, Ira M. Longini, Azhar Nizam et al.
How Vibrio cholerae spreads around the world and what determines its seasonal peaks in endemic areas are not known. These features of cholera have been hypothesized to be primarily the result of environmental factors associated with aquatic habitats that can now be identified. Since 1997, fortnightl...
Shah M. Faruque, Nityananda Chowdhury, Muhammad Kamruzzaman, Michelle Dziejman et al.
To understand the evolutionary events and possible selection mechanisms involved in the emergence of pathogenic Vibrio cholerae, we analyzed diverse strains of V. cholerae isolated from environmental waters in Bangladesh by direct enrichment in the intestines of adult rabbits and by conventional lab...
Shah M. Faruque, David A. Sack, R. Bradley Sack, Rita R. Colwell et al.
The emergence of Vibrio cholerae O139 Bengal during 1992-1993 was associated with large epidemics of cholera in India and Bangladesh and, initially, with a total displacement of the existing V. cholerae O1 strains. However, the O1 strains reemerged in 1994 and initiated a series of disappearance and...
Toshio Shimada, Eiji Arakawa, Kenichiro Itoh, Tadayuki Okitsu et al.
Soumen Chakraborty, Asish K. Mukhopadhyay, Rupak K. Bhadra, Amar N. Ghosh et al.
The virulence of a pathogen is dependent on a discrete set of genetic determinants and their well-regulated expression. The ctxAB and tcpA genes are known to play a cardinal role in maintaining virulence in Vibrio cholerae, and these genes are believed to be exclusively associated with clinical stra...
Munirul Alam, Marzia Sultana, G. Balakrish Nair, R. Bradley Sack et al.
Toxigenic Vibrio cholerae, rarely isolated from the aquatic environment between cholera epidemics, can be detected in what is now understood to be a dormant stage, i.e., viable but nonculturable when standard bacteriological methods are used. In the research reported here, biofilms have proved to be...
Kara Cooper, Cindy Kit Yee Luey, Michele M. Bird, Jun Terajima et al.
PulseNet is a network that utilizes standardized pulsed-field gel electrophoresis (PFGE) protocols with the purpose of conducting laboratory-based surveillance of foodborne pathogens. PulseNet standardized PFGE protocols are subject to rigorous testing during the developmental phase and careful eval...
Firdausi Qadri, Ashraful Islam Khan, Abu Syed Golam Faruque, Yasmin Ara Begum et al.
Flooding in Dhaka in July 2004 caused epidemics of diarrhea. Enterotoxigenic Escherichia coli (ETEC) was almost as prevalent as Vibrio cholerae O1 in diarrheal stools. ETEC that produced heat-stable enterotoxin alone was most prevalent, and 78% of strains had colonization factors. Like V. cholerae O...
M. Thungapathra, Amita, Kislay K. Sinha, Saumya Ray Chaudhuri et al.
Molecular mechanisms of multidrug resistance in Vibrio cholerae belonging to non-O1, non-O139 serogroups isolated during 1997 to 1998 in Calcutta, India, were investigated. Out of the 94 strains examined, 22 strains were found to have class I integrons. The gene cassettes identified were dfrA1, dfrA...
M. Ansaruzzaman, N. A. Bhuiyan, G. Balakrish Nair, David A. Sack et al.
To the Editor: Cholera outbreaks caused by toxigenic Vibrio cholerae serogroup O1 frequently occur in many sub-Saharan African countries. The serogroup O1 is classified into two biotypes, classical and El Tor. The seventh and current pandemic of cholera is caused by the El Tor biotype; the classical...
Munirul Alam, Nur A. Hasan, Abdus Sadique, N. A. Bhuiyan et al.
Since Vibrio cholerae O139 first appeared in 1992, both O1 El Tor and O139 have been recognized as the epidemic serogroups, although their geographic distribution, endemicity, and reservoir are not fully understood. To address this lack of information, a study of the epidemiology and ecology of V. c...
Abdullah Siddique, G. Balakrish Nair, Munirul Alam, David A. Sack et al.
During epidemics of cholera in two rural sites (Bakerganj and Mathbaria), a much higher proportion of patients came for treatment with severe dehydration than was seen in previous years. V. cholerae O1 isolated from these patients was found to be El Tor in its phenotype, but its cholera toxin (CT) w...
Santanu Chattopadhyay, Rajashree Patra, T. Ramamurthy, Abhijit Chowdhury et al.
We developed and evaluated a simple, novel multiplex PCR assay for rapid detection of Helicobacter pylori infection and for the determination of vacA and cagA genotypes directly from gastric biopsy specimens. This assay did not require culturing of strains or extraction of DNA from biopsy samples. T...
Asis Khan, Suresh Chandra Das, T. Ramamurthy, A. Sikdar et al.
Antibiotic resistance, virulence gene, and molecular profiles of Shiga toxin-producing Escherichia coli (STEC) non-O157 strains isolated from human stool samples, cow stool samples, and beef samples over a period of 2 years in Calcutta, India, were determined. Resistance to one or more antibiotics w...