The rugose colony variant of Vibrio cholerae O1, biotype El Tor, is shown to produce an exopolysaccharide, EPSETr, that confers chlorine resistance and biofilm-forming capacity. EPSETr production requires a chromosomal locus, vps, that contains sequences homologous to carbohydrate biosynthesis genes of other bacterial species. Mutations within this locus yield chlorine-sensitive, smooth colony ...

occurred around the world. Firm evidence indicates that the fi fth and sixth cholera pandemics were caused by the classical biotype whereas the most extensive and ongoing seventh pandemic is caused by the El Tor biotype. Since the onset of El Tor dominance in 1961, the classical strains have been gradually replaced by the El Tor strains and are now believed to be extinct. However, reports from ...

BACKGROUND & OBJECTIVES Factor causing the elimination of the classical biotype of Vibrio cholerae O1, and its replacement by the El Tor biotype causing the 7 th cholera pandemic are unclear. Possible ability of the El Tor strains to adapt better than the classical strains to undefined environmental forces have been largely implicated for the change. Here we describe an environmental bacterioph...

A PCR-based assay was developed to discriminate the classical, El Tor, and Haitian types of ctxB alleles. Our retrospective study using this newly developed PCR showed that Haitian ctxB first appeared in Kolkata during April 2006, and 93.3% of strains isolated during 2011 carried the new allele. Dendrogram analysis showed a pulsed-field gel electrophoresis (PFGE) pattern of the new variant stra...

Stool cultures from 510 patients, admitted to the Children's Ward of the Dr. Soetomo Hospital with gastroenteritis, were examined. Fifty-six cases were found to have para Cholera El Tor (10.98%) and 56 patients showed positive E. coli (10.98% ). The clinical features of para Cholera El Tor have been discussed, and compared with E. coli infections. We also reviewed the clinical observations of o...

Cholera is still an important public health problem in several countries, including Thailand. In this study, a collection of clinical and environmental V. cholerae serogroup O1, O139, and non-O1/non-O139 strains originating from Thailand (1983 to 2013) was characterized to determine phenotypic and genotypic traits and to investigate the genetic relatedness. Using a combination of conventional m...

Hemolysins purified from non-O1 Vibrio cholerae (non-O1 hemolysin) and a Vibrio cholerae O1, biotype El Tor (El Tor hemolysin) were investigated for their homology. The hemolysins were isolated from the culture supernatant fluids by ammonium sulfate precipitation and gel filtration on Sephadex G-100 columns. The purified hemolysins gave single bands with an identical mobility on conventional po...

The effect of lysogenization with five temperate phages from various sources on serotype and lytic phage sensitivity was investigated in six cultures of Vibrio cholerae of both classical and El Tor biotypes. No changes in serotype or in classical phage sensitivity in the classical biotype were observed. Four of the temperate phages were homoimmune and induced resistance to one of the El Tor typ...

Cholera remains a significant public health challenge in many sub-Saharan countries including Kenya. We have performed a combination of phylogenetic and phenotypic analysis based on whole genome DNA sequences derived from 40 environmental and 57 clinical V. cholerae from different regions of Kenya isolated between 2005 and 2010. Some environmental and all clinical isolates mapped back onto wave...

The recent outbreaks of cholera in Haiti, Pakistan, and Zimbabwe suggest that our current global action plans against cholera are failing. This issue contains two important articles that will help inform our discussions on ways to respond to the global cholera situation. Cholera is a severely dehydrating illness caused by Vibrio cholerae, a Gram-negative organism. V. cholerae exists in environm...