II-A. Systemic Bacteriology | 12. Corynebacterium. Listeria monocytogenes

Question 1

I. Corynebacterium
1. What is the natural habit of Corynebacterium?

Answer 1

only human pathogens: skin, mucosa

Question 2

I. Corynebacterium
1. What is the natural habit of Corynebacterium?

Answer 2

only human pathogens: skin, mucosa

Question 3

I. Corynebacterium
2. What is the morphology of Corynebacterium?

Answer 3

1. Slender pleomorphic Gram-positive rods or club
2. 4 biotypes: gravis, intermedius, belfanti, mitis
3. non spore forming, non motile
4. the cell contain metachromatic granules (Babes-Ernst volutin granules)
5. specific stain: Neisser stain, resembles chines letters

Question 4

I. Corynebacterium
4. What are the biotypes of Corynebacterium?

Answer 4

gravis, intermedius, belfanti, mitis

Question 5

I. Corynebacterium
5. What are the specific stains for Corynebacterium?

Answer 5

Neisser stain, resembles chines letters

Question 6

I. Corynebacterium
6. Describe the cultivation for Corynebacterium

Answer 6

only human pathogens: skin, mucosa

Question 7

I. Corynebacterium
7. Which culture media should we use for Corynebacterium?

Answer 7

Löffler and Clauberg culture media

Question 8

I. Corynebacterium
8. What is the colony morphology of Corynebacterium?

Answer 8

• gravis: 3-4 mm
• mitis – small and smooth
• intermediate
• belfanti

Question 9

I. Corynebacterium
9. Explain the pathogenesis of Corynebacterium

Answer 9

Early manifestations
- Pseudomembrane formation → ripped off bleeding will occur
+) Inflammatory rxn to the multiplying toxigenic C. diptheriae
+) Fluid and leukocytes move from dilated blood vessels to surround necrotic epithelial cells
+) Fluid clots to enmesh dead cells, leukocytes, diphtheria bacilli, cellular debris

Question 10

I. Corynebacterium
10A. What is the virulence factor of Corynebacterium?

Answer 10

diphtheria toxin - 535-amino acid, 62-kDa
(Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make toxin (poison)

Question 11

I. Corynebacterium
10B. What are the features of Diphtheria toxin?

Answer 11

1/ 3 Domains: A (enzymatic), B (binding), T (translocation)
2/ Result: cell death by apoptosis
3/ TOX gene expression is regulated by the bacterial chromosome

Question 12

I. Corynebacterium
11A. What are the pathological changes by Corynebacterium?

Answer 12

Changes can be in the myocardium, peripheral nerves, and kidneys

Question 13

I. Corynebacterium
11B. What are the cardiac changes caused by Corynebacterium?

Answer 13

fatty degeneration of cardiac muscle (myocarditis)

Question 14

I. Corynebacterium
11C. What are the neuritic changes caused by Corynebacterium?

Answer 14

• demyelination and degeneration of both sensory and motor nerves
• nerves to the eye, palate, pharynx, larynx, heart, and limb muscles

Question 15

I. Corynebacterium
12. How can Corynebacterium spread?

Answer 15

• upper respiratory system – by inhalation
• skin – direct contact
• the organism can survive for up to 5 weeks in dust or on fomites

Question 16

I. Corynebacterium
13A. What are the clinical symptoms of Corynebacterium?

Answer 16

• Mild disease → fatal infection
• Incubation period of 2-6 days
• Anterior Nasal
• Tonsillar → Most common
• Tracheolaryngeal
• Malignant

Question 17

I. Corynebacterium
13B. What are the clinical symptoms in Anterior Nasal caused by Corynebacterium?

Answer 17

○ Nasal discharge, initially watery, then purulent and blood stained
○ Nostril may be sore or crusted and a thin pseudomembrane

Question 18

I. Corynebacterium
13B. What are the clinical symptoms in Tonsillar (faucial) caused by Corynebacterium?

Answer 18

1. Malaise, sore throat, moderate fever
2. Small, yellowish pseudomembrane on tonsils…few days pass → cover uvula soft palate, nasopharynx or larynx
3. Cervical lymphadenopathy, nausea, vomiting, and painful dysphagia

Question 19

I. Corynebacterium
13C. What are the Tracheolaryngeal symptoms caused by Corynebacterium?

Answer 19

• Moderate fever, hoarseness and non-productive cough
• 1-2days → pseudomembrane and associated edema spread → increasingly dyspnoeic w/
  severe chest recession, cyanosis
• Tracheostomy

Question 20

I. Corynebacterium
13D. What are the Malignant symptoms caused by Corynebacterium?

Answer 20

• High fever, tachycardia, hypotension, cyanosis
• Pseudomembrane moves from tonsils to nasopharynx
• Gross cervical lymphadenopathy
• Surrounding edema → bull neck
• Bleeding from mouth, nose or skin
• Heart block in a few days
• Acute renal failure – survival in unlikely

Question 21

I. Corynebacterium
14. How can we diagnose diseases caused by Corynebacterium

Answer 21

1. Send to lab for microscope examination and cultivation
2. Elek Test → examination of toxin production
3. Schick test → intradermal

Question 22

I. Corynebacterium
15. What is the therapy for Corynebacterium?

Answer 22

• ampicillin – against bacteria (erythromycin)
• administration of antitoxin – for neutralising of the toxin

Question 23

I. Corynebacterium
16. How do we prevent Corynebacterium?

Answer 23

DTaP active immunisation (toxoid) – since 1938

Question 24

I. Corynebacterium
17. Give example of Diphtheroids

Answer 24

Question 25

II. Listeria monocytogenes 1. What is Listeria monocytogenes?

Answer 25

● Listeria monocytogenes is the species of pathogenic bacteria that causes the infection listeriosis

Question 26

II. Listeria monocytogenes 2. Give examples of Listeria monocytogenes

Answer 26

* the genus Listeria consists of 10 species * Listeria monocytogenes and Listeria ivanovii – pathogens * L. monocytogenes – human pathogen * L. ivanovii - animal pathogen

Question 27

II. Listeria monocytogenes 3. What is the natural habitat of Listeria monocytogenes?

Answer 27

It is ubiquitous, in intestine of animals

Question 28

II. Listeria monocytogenes 4. Describe the morphology of Listeria monocytogenes?

Answer 28

- Gram-positive, facultative anaerobic rod - short: 0.4μm×2μm, nonbranching - non motile at 37oC - only at room temperature - can grow at 1-45oC – cold enrichment

Question 29

II. Listeria monocytogenes 5. Describe the cultivation of Listeria monocytogenes?

Answer 29

1. incubation time: - at 35oC 24-72 hours - at 4oC 7-30 days 2. on blood agar: ß haemolysis

Question 30

II. Listeria monocytogenes 6. What are biochemical properties of Listeria monocytogenes?

Answer 30

- catalase +, can tolerate 10% of NaCl - CAMP positive

Question 31

II. Listeria monocytogenes 7. How do we use Listeria monocytogenes for epidemiological research?

Answer 31

serological identification and phagetyping necessary

Question 32

II. Listeria monocytogenes 8. What are the features and demography of Listeriosis?

Answer 32

Question 33

II. Listeria monocytogenes 9. Describe Pathogenesis and immunity of Listeria monocytogenes

Answer 33

Question 34

II. Listeria monocytogenes 10A. What are the virulence factors of Listeria monocytogenes?

Answer 34

1. internalin - entering in cell 2. listeriolysin - lysis of phagosome 3. ActA - polymerization of actines

Question 35

II. Listeria monocytogenes 10B. What is the role of listeriolysin?

Answer 35

lysis of phagosome

Question 36

II. Listeria monocytogenes 10C. What are the symptoms caused by Listeria monocytogenes?

Answer 36

- asymptomatic - resembling mild flu - meningitis - skin infection – animal breeders

Question 37

II. Listeria monocytogenes 11. How does immunity respond to Listeria monocytogenes?

Answer 37

1. humoral immunity - unimportant (intracellular bacteria) 2. patients with defects in cellular immunity, but not in humoral immunity, are particularly susceptible to severe infections

Question 38

II. Listeria monocytogenes 13. Explain epidemiology of Listeria monocytogenes

Answer 38

Epidemiology: Feces of mammals, birds and fish ● Human to human transmission → mother to child in utero or at birth ● Faecal carriage 1% to 5% of healthy people ● Large outbreaks occur with contaminated foods

Question 39

II. Listeria monocytogenes 14. What are the clinical diseases caused by Listeria monocytogenes

Answer 39

meningitis, sepsis, granulomatosis infantiseptica, endocarditis, GIT problems)

Question 40

II. Listeria monocytogenes 15. Explain neonatal diseases caused by Listeria monocytogenes

Answer 40

- early onset disease - acquired transplacentally in utero - Late-onset disease - acquired at or soon after birth

Question 41

I. Listeria monocytogenes 16. Explain the clinical disease caused by Listeria monocytogenes in pregnant women

Answer 41

● 3rd trimester - cellular immunity is most impaired ● Infected women: nonspecific influenza symptoms -- may resolve without treatment

Question 42

I. Listeria monocytogenes 17. Explain the clinical disease caused by Listeria monocytogenes in healthy adults

Answer 42

● Most common → asymptomatic or mild influenza-like illness ● Acute, self-limited gastroenteritis (fever, headache, nausea, myalgias, and arthralgias)

Question 43

I. Listeria monocytogenes 18. Explain Meningitis caused by Listeria monocytogenes in adults

Answer 43

● Most common form of disseminated listeriosis ● Listeria should be suspected in patients with organ transplants or cancer and in pregnant women

Question 44

I. Listeria monocytogenes 19A. What is the Laboratory Diagnosis for Listeria monocytogenes

Answer 44

- Microscopy - Serology

Question 45

I. Listeria monocytogenes 19B. How do we do microscopy in Laboratory Diagnosis for Listeria monocytogenes

Answer 45

- Gram-stain: cerebrospinal fluid usually negative - Gram-stain shows intracellular and extracellular gram- positive coccobacilli

Question 46

II. Listeria monocytogenes 19C. How do we do serology in Laboratory Diagnosis for Listeria monocytogenes

Answer 46

- 13 serotypes: 1/2a, 1/2b, and 4b are responsible for most infections - serotyping is generally not useful in epidemiologic investigations - Pulsed-field gel electrophoresis (PFGE) is the most commonly used method

Question 47

II. Listeria monocytogenes 20. How do we treat Listeria monocytogenes?

Answer 47

most antibiotics are only bacteriostatic w. L. monocytogenes ● Combination of gentamicin with ampicillin is the treatment of choice ● Naturally resistance: cephalosporins ● Acquired resistance: macrolides, tetracyclines and fluoroquinolones ● Trimethoprim/sulfamethoxazole is bactericidal

Question 48

II. Listeria monocytogenes 21. Do we have vaccine for Listeria monocytogenes?

Answer 48

vaccine is not available