A Rough Variant of Nontoxigenic Vibrio Cholerae O139 Imported From Vietnam

Purpose (stating the main purposes and research question)Vibrio cholerae is classified in O-antigen polysaccharide outer membrane properties where O1 and O139 are strains that cause pandemics and epidemics while non-O1/non-O139 usually cause mild disease. The dynamic evolution of Vibrio cholerae involves new virulence factors through horizontal gene transfer and formerly nontoxigenic serogroups are being reported as causing increasingly severe forms of human disease. Our purpose was to investigate serogroup and virulence factors in one imported isolate from Vietnam and compare these to virulence factors seen in different strains of Vibrio cholerae.MethodsWe have serotyped one isolate of imported Vibrio cholerae from Vietnam to Denmark and performed whole genome sequencing to identify known virulence genes. ResultsWe have identified virulence factors in our isolate that are recently discovered and one toxin, MakA, has not previously been reported from an Asian strain. The isolate was found to be a serogroup non-O1/non-O139 strain, however, sequence analysis gave a 96, 6% ID match of the wbfZ gene, stipulating our isolate to belong to either serogroup O22 or O139. ConclusionsLooking at the combination of virulence factors of the isolate we suggest the finding of a rough variant of a nontoxigenic Vibrio cholerae O139 rather than a O22 serogroup version. This is a rare finding in a clinical isolate.

Vibrio cholerae O139 persists in Dhaka, Bangladesh since 1993

Background After a multi-country Asian outbreak of cholera due to Vibrio cholerae serogroup O139 which started in 1992, it is rarely detected from any country in Asia and has not been detected from patients in Africa. Methodology/Principal findings We extracted surveillance data from the Dhaka and Matlab Hospitals of International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) to review trends in isolation of Vibrio cholerae O139 in Bangladesh. Data from the Dhaka Hospital is a 2% sample of > 100,000 diarrhoeal patients treated annually. Data from the Matlab Hospital includes all diarrhoeal patients who hail from the villages included in the Matlab Health and Demographic Surveillance System. Vibrio cholerae O139 was first isolated in Dhaka in 1993 and had been isolated every year since then except for a gap between 2005 and 2008. An average of thirteen isolates was detected annually from the Dhaka Hospital during the last ten years, yielding an estimated 650 cases annually at this hospital. During the last ten years, cases due to serogroup O139 represented 0.47% of all cholera cases; the others being due to serogroup O1. No cases with serogroup O139 were identified at Matlab since 2006. Clinical signs and symptoms of cholera due to serogroup O139 were similar to cases due to serogroup O1 though more of the O139 cases were not dehydrated. Most isolates of O139 remained sensitive to tetracycline, ciprofloxacin, and azithromycin, but they became resistant to erythromycin starting in 2009. Conclusions/Significance Cholera due to Vibrio cholerae serogroup O139 continues to cause typical cholera in Dhaka, Bangladesh.

Defining Polysaccharide-Specific Antibody Targets against Vibrio cholerae O139 in Humans following O139 Cholera and following Vaccination with a Commercial Bivalent Oral Cholera Vaccine, and Evaluation of Conjugate Vaccines Targeting O139

Cholera is a severe dehydrating illness of humans caused by Vibrio cholerae serogroup O1 or O139. Protection against cholera is serogroup specific, and serogroup specificity is defined by O-specific polysaccharide (OSP).