II-A. Systemic bacteriology | 17. Brucella and Francisella genus

Question 1

I. Brucella genus
1. What are the features of Brucella genus?

Answer 1

Gram-negative coccobacilli / short rods

Question 2

I. Brucella genus
2. What are important species of Brucella genus?

Answer 2

species were named based on host animal
* B. melitensis – goat, sheep
* B. suis – swine
* B. abortus – cow
* B. canis - dog

Question 3

I. Brucella genus
3. What is the route of transmission of Brucella genus?

Answer 3

route of transmission: zoonosis!
- bacterium spreads with animal secretions, milk ( pasteurisation can kill them!)

Question 4

I. Brucella genus
4. What is the entry site of Brucella genus?

Answer 4

Entry site: infection through skin/mucous membrane lesion (alimentary)
- bacteria infects RES, can be found intracellulary → granulomas

Question 5

I. Brucella genus
5. What is the disease caused by Brucella genus?

Answer 5

brucellosis (“great imitator”) – aspecific symptoms

Question 6

I. Brucella genus
6. What are the symptoms of brucellosis (“great imitator”) – aspecific symptoms?

Answer 6

fever (FUO), insomnia, irritability + organ dysfunctions

Question 7

I. Brucella genus
7. Can brucellosis infect organs

Answer 7

• spleen abscess, liver abscess, granulomas
• lymphadenopathy, blood stream infection, endocarditis
• cerebral abscess, meningitis, osteomyelitis
• orchitis, chorioretinitis

Question 8

I. Brucella genus
8. What are infections caused by Brucella genus?

Answer 8

• febris melitensis (maltan fever) → B. melitensis
• febris undulans (Bang-disease) → B. abortus

Question 9

I. Brucella genus
9A. How do we diagnose Brucella genus?

Answer 9

• aspecific symptoms, might imitate anything ➡ should think about it (farm workers, unpasteurized dairy product consumption!)
• sampling
• laboratory

Question 10

I. Brucella genus
9B. How do we sample to diagnose Brucella genus?

Answer 10

blood culture, aspirate (lymphnodes), bone marrow, blood (for serology)

Question 11

I. Brucella genus
9C1. How do we do laboratory to diagnose Brucella genus?

Answer 11

1. serology (tube agglutination, ELISA, IF)
   - Wright-tube agglutination: patient serum is mixed with known Brucella bacteria ➡ if agglutination happens, it proves, that the patient has antibodies against the bacterium)
2. PCR
   - culturing (rarely, only in specific laboratories)

Question 12

I. Brucella genus
9C2. What is Wright-tube agglutination?

Answer 12

Wright-tube agglutination: patient serum is mixed with known Brucella bacteria ➡ if agglutination happens, it proves, that the patient has antibodies against the bacterium)

Question 13

I. Brucella genus
10. What is the empirical therapy for Brucella genus?

Answer 13

• tetracyclines + rifampicin
• aminoglycosides

Question 14

I. Brucella genus
10. What is the prevention for Brucella genus?

Answer 14

• vaccination of livestock
• pasteurization of dairy products
• category B bio-weapon!

Question 15

II. Francisella genus
1. What are the features of Francisella genus?

Answer 15

• Gram Negative (-)
• Small rod or coccobacilli
• Facultative intracellular
  (category A bio-weapon!)

Question 16

II. Francisella genus
2. What is the important species of Francisella genus?

Answer 16

Francisella tularensis

Question 17

II. Francisella genus
6A. How should we diagnose Francisella tularensis?

Answer 17

• based on clinical signs and symptoms
• sampling: blood (for serology), conjunctiva swab, lymph node aspirate
• laboratory: tube agglutination, ELISA, IF

Question 18

II. Francisella genus
6B. How should we do laboratory to diagnose Francisella tularensis?

Answer 18

tube agglutination, ELISA, IF

Question 19

II. Francisella genus
3. What is the source of infection of Francisella tularensis?

Answer 19

zoonotic diseases (small rodents for e.g. rabbits)
- animal products
- tick bite

Question 20

II. Francisella genus - Francisella tularensis
4. What is the route of transmission of Francisella tularensis?

Answer 20

Infection through skin/mucous membrane lesion, per os
- intracellular localisation (proliferates in macrophages)

Question 21

II. Francisella genus
2. What is the important species of Francisella genus?

Answer 21

Francisella tularensis

Question 22

II. Francisella genus
7. What is the prevention for Francisella genus

Answer 22

PPE, livestock vaccination

Question 23

II. Francisella genus
8. What is the empirical therapy for Francisella genus

Answer 23

aminoglycosides, tetracyclines