AEROBIC GRAM-NEGATIVE BACTERIA: VIBRIO AND SIMILAR MICROORGANISMS

General characteristics

a. Most are Indole ____

b. All are Oxidase ____ except V. _____

c. Some of the species causes _____ disease

a. Most are Indole POSITVE

b. All are Oxidase POSITIVE except V. metschikovii

c. Some of the species causes GI disease

• The genus contains about 30 species that are inhabitants of marine water

• All species are halophilic (salt-loving) except V. cholerae and V. mimicus

• V. ____ - is sucrose _____ and will produce ____ colonies on TCBS agar

• V. _____ - is sucrose ___.

• V. cholerae - is sucrose positive and will produce yellow colonies on TCBS agar, whereas

• V. parahaemolyticus - is sucrose negative.

__________ agar

- a selective and differential (based on ____ fermentation) medium that supports the growth of most species and is particularly useful for isolating V. cholerae and V. parahaemolyticus.

Thiosulfate-citrate- bile salt sucrose (TCBS)

sucrose

Most laboratories use _____ to presumptively identify species and then confirm with ______ with antisera against somatic O antigens

Most laboratories use biochemical testing to presumptively identify species and then confirm with slide agglutination with antisera against somatic O antigens

• Acquired by ingestion of undercooked seafood or contaminated drinking water.

• Cases can also be acquired via the fecal-oral route.

Vibrio cholerae

• _________ serologic group that causes cholera, characterized by severe watery diarrhea with flecks of mucus sometimes referred to as “rice water stool”

• It is subdivided into three serotypes: ____, ____, ____

• It has two biotypes:_____ and ____

V. cholerae O1

• Inaba, Ogawa, and Hikojima

• Classical and El Tor.

• ______: generally cause a mild choleralike illness.

• ______ : produces severe disease similar to V. cholerae O1

• Serogroups non-O1

• Serogroup O139

• Important cause of food poisoning in Asia, particulary in Japan and Taiwan 

• Acquired by eating raw shellfish

• Causes a mild to moderate choleralike diarrhea disease 

Vibrio parahaemolyticus

• Highly virulent, causing septicemia after ingestion of undercooked seafood, notably raw oysters

• Causes a rapidly progressive wound infection that can result in a septicemia after exposure to marine water

Vibrio vulnificus

• Very common in marine environment

• Suspected causes of otitis media and wound infections

Vibrio alginolyticus

• Found in fresh and salt water

• Infects humans and fish

• Causes cellulitis and diarrhea

• Generally cause a self-limiting infection not usually requiring treatment; however, wound infections may require antimicrobial therapy.

Aeromonas

• Dogs and cats can also be reservoirs.

• Are a major cause of food poisoning, causing gastroenteritis, diarrhea, and septic arthritis.

• Infection is acquired by eating undercooked contaminated poultry or other meat products.

Campylobacter

• On wet mount, they will show darting motility.

• Curved bacilli that may appear S- shaped or spiral on Gram stain

• They do not oxidize or ferment carbohydrates, and most human isolates are catalase and oxidase positive.

Campylobacter

• Isolated from gastric biopsy on: SBA, Brucella, Skirrow’s agars Incubated microaerophilically.

• Causes peptic and duodenal ulcers and has been linked to stomach cancer.

Helicobacter pylori