G-

Newly isolated bacteria are arc-shaped or comma-shaped. After artificial culture, it becomes rod-shaped. Direct microscopic examination of feces shows that they are arranged like a school of fish.

The bacterial body has a single flagellum at one end and is active in movement.

Pili, no spores, group O139 has capsule

2 circular chromosomes

Prophage genome → produces cholera toxin

facultative anaerobic

Not high nutritional requirements

Alkali-resistant but not acid-resistant

Isolation culture

Ferment various sugars, producing acid but not gas

Reduced nitrate, positive indole test

Positive oxidase and catalase tests (unlike Enterobacteriaceae)

Thermostable O antigen—group specific

Thermolabile H antigen—nonspecific

The classical biotype of group O1 does not dissolve sheep red blood cells and does not agglutinate chicken red blood cells, whereas the El Tor type does the opposite.

Cholera toxin (the most powerful of the diarrheal toxins)

Factors related to colonization

Group O139 has a capsule and specific LPS virulence determinants

O1 and O139 groups

Non-O1 and O139 groups

The acquired immunity cannot cross-protect against O139 group infection and can protect against other infections.

Isolate and treat patients, promptly replenish water and electrolytes, and prevent hypovolemic shock and acidosis.