FASTIDIOUS GRAM NEGATIVE RODS. PART 7

Question 1

in what animal does brucella species cause diseases

Answer 1

Brucella spp. causes infection in cattle

Question 2

What are the routes of exposure for acquiring Brucella infections?

Answer 2

Brucella infections can be acquired through aerosol, percutaneous (through the skin), and oral routes of exposure.

Question 3

Who is primarily at risk for brucellosis

Answer 3

Brucellosis is primarily seen in individuals who are animal handlers and those who handle animal products.

Question 4

What are the other names for brucellosis?

Answer 4

Brucellosis is also known as Malta fever or undulant fever.

Question 5

What type of biohazard is associated with Brucella spp.?

Answer 5

Brucella spp. is classified as a Type 3 biohazard, which means it can be transmitted even through unbroken skin

Question 6

How is Brucella categorized as a biological agent?

Answer 6

Brucella is categorized as a Category B Biological agent, which indicates that it is easy to disseminate and can cause moderate morbidity, but has low mortality.

Question 7

explain the pathogenesis of brucella species

Answer 7

1. The organisms enter the body either by
   * Ingestion of contaminated milk products or
   * Through the skin by direct contact in an occupational setting such as an abattoir.
2. They localize in the reticuloendothelial system; the lymph nodes, liver,
   spleen, and bone marrow.
3. Many organisms are killed by macrophages, but some survive within these cells, where they are protected
   from antibody.
4. The host response is granulomatous, with lymphocytes and epithelioid giant cells, which can progress to
   form focal abscesses.
5. The mechanism of pathogenesis of these organisms is not well defined, except that endotoxin is involve

Question 8

what are the clinical findings of brucella

Answer 8

1. After an incubation period of 1 to 3 weeks, nonspecific symptoms such as
   fever,chills, fatigue, malaise, anorexia, and weight loss occur.
2. Enlarged lymph nodes, liver, and spleen are frequently found.
3. Pancytopenia occurs

Question 9

explain the colony morphology of brucella

Answer 9

1. Small, smooth, convex, nonhemolytic
2. May require holding culture for 21 days

Question 10

gram staining morphology of brucella

Answer 10

1. Small gram-negative coccobaccilli
2. Nonmotile
3. Aerobic
4. Oxidase positive
5. Catalase positive
6. Urease positive

Question 11

explain the lab diagnosis for brucella

Answer 11

1. Presumptively identified by using a slide agglutination test with Brucella
   antiserum.
2. Species can be identified by biochemical tests.

Question 12

Treatment for brucella species

Answer 12

Tetracycline plus Rifampin

Question 13

Prevention of brucella

Answer 13

1. Pasteurization of milk
2. Immunization of animals
3. Slaughtering of infected animals