A total of 330 clinical Vibrio cholerae O1 serogroups from China dating between 1961 and 2010 were investigated. By phenotypic biotyping and genetic analysis, during the seventh pandemic of V. cholerae O1 in China, the isolates of hybrid biotype (mixed classical phenotypes) were present during the entire1961-2010 period, while El Tor genetic shifts appeared in 1992 and replaced the prototype El...

Vibrio cholerae O1 strains belonging to both biotypes (classical and El Tor) and both serotypes (Ogawa and Inaba) produced neuraminidase which was released rather than cell bound. Classical strains made more neuraminidase than did El Tor strains. About one-third of V. cholerae non-O1 strains and one-fourth of Aeromonas hydrophila strains were neuraminidase positive. Strains of enterotoxigenic E...

The haemolytic properties of El Tor vibrios are usually utilized to differentiate them from the non-haemolytic cholera vibrios. In some freshly isolated Vibrio el tor strains, however, the haemolytic property may be ill-developed and this test may then fail to reveal the true identity of the strains. In order to overcome this difficulty a number of tests have been developed. Investigations repo...

Recently, Takeya and Shimodori (J. Bacteriol. 85:957, 1963) reported that every known strain of Celebes type El Tor vibrio is lysogenic and produces a characteristic temperate phage which has a very narrow host range. Further studies have revealed that 136 of 138 strains of El Tor vibrio isolated in the epidemic of the West Pacific from 1959 to 1963 were lysogenic and that all the temperate pha...

Vibrio cholerae serogroup O1 has historically been thought to be the exclusive cause of epidemic cholera. O139 is a novel serogroup of V. cholerae which emerged on the Indian subcontinent in the last few months of 1992 and is the first non-O1 serogroup of V. cholerae to cause epidemic cholera. We have investigated the expression of some of the known virulence factors of classical and El Tor O1 ...

Biochemical and physiological traits of a collection of strains of Vibrio cholerae O139 Bengal isolated from India, Bangladesh, and Thailand showed that these strains formed a phenotypically homogeneous group with identical characteristics that were essentially similar to those of the O1 serogroup. Resistance to 150 micrograms of the vibriostatic agent O/129 (2,4-diamino-6,7-diisopropylpteridin...

IEM101, a Vibrio cholerae O1 El Tor Ogawa strain naturally deficient in CTXPhi, was previously selected as a live cholera vaccine candidate. To make a better and safer vaccine that can induce protective immunity against both the bacteria and cholera toxin (CT), a new vaccine candidate, IEM108, was constructed by introducing a ctxB gene and an El Tor-derived rstR gene into IEM101. The ctxB gene ...

Epidemic strains of Vibrio cholerae O1 are divided into two biotypes, classical and El Tor. In both biotypes, regulation of virulence gene expression depends on a cascade in which ToxR activates expression of ToxT, and ToxT activates expression of cholera toxin and other virulence genes. In the classical biotype, maximal expression of this ToxR regulon in vitro occurs at 30 degrees C at pH 6.5 ...

Toxigenic serogroups O1 and O139 of Vibrio cholerae may cause cholera epidemics or pandemics. Nontoxigenic strains within these serogroups also exist in the environment, and also some may cause sporadic cases of disease. Herein, we investigate the genomic diversity among toxigenic and nontoxigenic O1 and O139 strains by comparative genomic microarray hybridization with the genome of El Tor stra...

Hemolytic Vibrio cholerae biotype El Tor strains were isolated in the United States in 1973 and 1978 after they had supposedly disappeared worldwide during the 1960s and 1970s. We decided to examine the change in prevalence of hemolytic El Tor strains since the beginning of the seventh pandemic and evaluate the usefulness of hemolytic activity as an epidemiological marker. A total of 48 isolate...