Vibrios are motile, rod-shaped, facultativeanaerobic, gram-negative bacteria that can cause gastroenteritis, wound infection, and septicemia in humans. They are naturally found in marine, estuarine, and brackish waters in the United States and in other parts of the world. In the United States, they are recovered from the environment most commonly in summer and fall, when the water is warm. Vibrios have also been isolated from a variety of fish and shellfish, including oysters, clams, mussels, crabs, and shrimp. Human cases of illness associated with Vibrio infection occur mostly in summer and fall, and usually follow ingestion of raw or undercooked shellfish, particularly oysters, or exposure of a wound to fish, shellfish, or seawater. In countries with endemic or epidemic cholera, infection with Vibrio cholerae may occur after ingestion of any contaminated food or water; in the United States, cholera is endemic along the Gulf Coast.

Analysis of 5S ribosomal ribonucleic acid sequence revealed 34 Vibrio spp., 12 of which have been isolated from human clinical specimens. The major clinical presentations associated with infection with these 12 species are shown in Table 157.1. Rarely, vibrios have also been recovered from bone, cerebrospinal fluid, ear, gallbladder, sputum, and urine.