Cholera, also known as "blue death" is a potentially epidemic and life-threatening secretory diarrhea characterized by numerous voluminous watery stools, often accompanied by vomiting and resulting in hypovolemic shock and acidosis. The causative agent of this water-borne disease belongs to certain members of the species Vibrio cholerae (V. cholerae) which can also cause mild or unapparent infections. V. cholerae is a facultative anaerobic, Gram-negative bacilli, which possess the characteristic feature of darting motility under wet-mound preparations. Other members of the species may occasionally cause isolated outbreaks of milder diarrhea, whereas others-the vast majority-are free-living and not associated with disease. The emergence of new, virulent, drug-resistant strains of Vibrio is the main cause of protracted outbreaks leading to high fatality rates. The subsequent loss of fluid volume causes a drop in blood pressure and circulatory shock. If the patient remains untreated, they become progressively weaker, sometimes to the point of death, within 12-24 h of the onset of symptoms. The severity and fatality of the disease depend on the strain of Vibrio. The cholera toxin-producing (CT-producing) V. cholerae manifests the most fatal disease known as cholera gravis. Throughout most of the twentieth century, cholera was caused by V. cholerae of the O1 serogroup, and the disease was largely confined to Asia and Africa. The emergence of a pandemic in 1992 was caused by an unknown serogroup of V. cholerae (O139) wherein the targets were India and Bangladesh. The pathogenesis and virulence of the bacteria are due to an enterotoxin it producescholera toxin (CT). The mechanism of action of CT is discussed in this chapter at a later stage. Attempts have been made to produce vaccines through a number of trial-and-error methods, and still the possibility of an effective vaccine which gives a good prophylactic measure is under consideration. The identification of the bacteria as well as toxin detection is one of the main elements in the clinical microbiology field. The identification and confirmation of this epidemic disease commend from the morphological identification of Vibrio and end with serotyping and biotyping in addition to toxin detection by various means of assays-both in vitro and in vivo. This chapter will cover all of the mentioned areas of clinical microbiology with respect to cholera infection in addition to the recent outbreaks and epidemics which occurred across the globe.

The present study was aimed to evaluate the physicochemical, phytochemical screening and antimicrobial assessment of Aegle marmelos fruits extract. The powder was evaluated for loss on drying, alcohol extractive value and aqueous extractive value. The petroleum ether, ethanol and aqueous extract were prepared by soxhlet extraction process. The phytochemical analysis of extracts was performed, and antimicrobial activity of ethanol extracts against various strains was done. The loss on drying, alcohol and aqueous extractive values were 3.9%, 14.2% and 17.6%, respectively. Phytochemical analysis showed the presence of carbohydrates, alkaloids, glycoside, flavonoids, saponins, tannins phenols in ethanol extracts. The ethanol extracts demonstrated moderate to strong antimicrobial activity against S. epidermis, S. aureus, E. coli, P. aeruginosa and C. albicans. Thus in future, extract of Aegle marmelos may be beneficial for another several species of microbes.

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