Integration of Global Regulatory Mechanisms Controlling Vibrio Cholerae Behavior

Abstract

Cholera is an acute water-borne diarrheal disease caused by the facultative Gram-negative bacterium Vibrio cholerae of serogroup O1 of the classical and El Tor biotypes and serogroup O139. Characteristics of this bacterium are its comma-shaped morphology, expression of a fast-rotating polar flagellum, and production of cholera toxin (CT). The O1 V. cholerae serogroup contains a common A antigen and can be subdivided in Ogawa and Inaba serotypes on the basis of serotype-specific antigens B and C, respectively (Kaper et al., 1995). Mankind has experienced seven recorded cholera pandemics. The seventh and current pandemic is characterized by the predominance of the O1 serogroup El Tor biotype, with periodic emergence of O139 strains, which exhibit a new lipopolysaccharide (LPS) and a capsule (Albert, 1994). Cholera, which continues to be a major public health concern in endemic areas of South Asia and Africa, is estimated to cause 5.5 million cases of disease and 130,000 deaths per year. The disease, which commonly occurs as rapidly spreading and difficult to contain outbreaks in low-income countries, is a common sequel of natural and human disasters. The typical cholera symptoms include a profuse ricewatery diarrhea and vomiting. If untreated, this condition can lead to severe dehydration, electrolyte imbalances, and death. Cholera infections can be effectively treated with oral rehydration and, in cases of severe illness, with antibiotics. Antibiotic treatment lessens the duration of illness and reduces the excretion of highly infective Vibrios (Nelson et al., 2011). The downside however, is the emergence of multiple-antibiotic resistant O1 and O139 strains (Das & Kaur, 2008; Roychowdhury et al., 2008; Okeke et al., 2007; Mwansa et al., 2007; Faruque et al., 2007).