II-A. Systemic Bacteriology | 12. Corynebacterium. Listeria monocytogenes Flashcards
I. Corynebacterium
1. What is the natural habit of Corynebacterium?
only human pathogens: skin, mucosa
I. Corynebacterium
1. What is the natural habit of Corynebacterium?
only human pathogens: skin, mucosa
I. Corynebacterium
2. What is the morphology of Corynebacterium?
- Slender pleomorphic Gram-positive rods or club
- 4 biotypes: gravis, intermedius, belfanti, mitis
- non spore forming, non motile
- the cell contain metachromatic granules (Babes-Ernst volutin granules)
- specific stain: Neisser stain, resembles chines letters
I. Corynebacterium
4. What are the biotypes of Corynebacterium?
gravis, intermedius, belfanti, mitis
I. Corynebacterium
5. What are the specific stains for Corynebacterium?
Neisser stain, resembles chines letters
I. Corynebacterium
6. Describe the cultivation for Corynebacterium
only human pathogens: skin, mucosa
I. Corynebacterium
7. Which culture media should we use for Corynebacterium?
Löffler and Clauberg culture media
I. Corynebacterium
8. What is the colony morphology of Corynebacterium?
- gravis: 3-4 mm
- mitis – small and smooth
- intermediate
- belfanti
I. Corynebacterium
9. Explain the pathogenesis of Corynebacterium
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
I. Corynebacterium
10A. What is the virulence factor of Corynebacterium?
diphtheria toxin - 535-amino acid, 62-kDa
(Diphtheria is a serious infection caused by strains of bacteria called Corynebacterium diphtheriae that make toxin (poison)
I. Corynebacterium
10B. What are the features of Diphtheria toxin?
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
I. Corynebacterium
11A. What are the pathological changes by Corynebacterium?
Changes can be in the myocardium, peripheral nerves, and kidneys
I. Corynebacterium
11B. What are the cardiac changes caused by Corynebacterium?
fatty degeneration of cardiac muscle (myocarditis)
I. Corynebacterium
11C. What are the neuritic changes caused by Corynebacterium?
- demyelination and degeneration of both sensory and motor nerves
- nerves to the eye, palate, pharynx, larynx, heart, and limb muscles
I. Corynebacterium
12. How can Corynebacterium spread?
- upper respiratory system – by inhalation
- skin – direct contact
- the organism can survive for up to 5 weeks in dust or on fomites
I. Corynebacterium
13A. What are the clinical symptoms of Corynebacterium?
- Mild disease → fatal infection
- Incubation period of 2-6 days
- Anterior Nasal
- Tonsillar → Most common
- Tracheolaryngeal
- Malignant
I. Corynebacterium
13B. What are the clinical symptoms in Anterior Nasal caused by Corynebacterium?
○ Nasal discharge, initially watery, then purulent and blood stained
○ Nostril may be sore or crusted and a thin pseudomembrane
I. Corynebacterium
13B. What are the clinical symptoms in Tonsillar (faucial) caused by Corynebacterium?
- Malaise, sore throat, moderate fever
- Small, yellowish pseudomembrane on tonsils…few days pass → cover uvula soft palate, nasopharynx or larynx
- Cervical lymphadenopathy, nausea, vomiting, and painful dysphagia
I. Corynebacterium
13C. What are the Tracheolaryngeal symptoms caused by Corynebacterium?
- Moderate fever, hoarseness and non-productive cough
- 1-2days → pseudomembrane and associated edema spread → increasingly dyspnoeic w/
severe chest recession, cyanosis - Tracheostomy
I. Corynebacterium
13D. What are the Malignant symptoms caused by Corynebacterium?
- 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
I. Corynebacterium
14. How can we diagnose diseases caused by Corynebacterium
- Send to lab for microscope examination and cultivation
- Elek Test → examination of toxin production
- Schick test → intradermal
I. Corynebacterium
15. What is the therapy for Corynebacterium?
- ampicillin – against bacteria (erythromycin)
- administration of antitoxin – for neutralising of the toxin
I. Corynebacterium
16. How do we prevent Corynebacterium?
DTaP active immunisation (toxoid) – since 1938
I. Corynebacterium
17. Give example of Diphtheroids
II. Listeria monocytogenes
1. What is Listeria monocytogenes?
● Listeria monocytogenes is the species of pathogenic bacteria that causes the infection listeriosis
II. Listeria monocytogenes
2. Give examples of Listeria monocytogenes
- the genus Listeria consists of 10 species
- Listeria monocytogenes and Listeria ivanovii – pathogens
- L. monocytogenes – human pathogen
- L. ivanovii - animal pathogen
II. Listeria monocytogenes
3. What is the natural habitat of Listeria monocytogenes?
It is ubiquitous, in intestine of animals
II. Listeria monocytogenes
4. Describe the morphology of Listeria monocytogenes?
- 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
II. Listeria monocytogenes
5. Describe the cultivation of Listeria monocytogenes?
- incubation time:
- at 35oC 24-72 hours
- at 4oC 7-30 days - on blood agar: ß haemolysis
II. Listeria monocytogenes
6. What are biochemical properties of Listeria monocytogenes?
- catalase +, can tolerate 10% of NaCl
- CAMP positive
II. Listeria monocytogenes
7. How do we use Listeria monocytogenes for epidemiological research?
serological identification and phagetyping necessary
II. Listeria monocytogenes
8. What are the features and demography of Listeriosis?
II. Listeria monocytogenes
9. Describe Pathogenesis and immunity of Listeria monocytogenes
II. Listeria monocytogenes
10A. What are the virulence factors of Listeria monocytogenes?
- internalin - entering in cell
- listeriolysin - lysis of phagosome
- ActA - polymerization of actines
II. Listeria monocytogenes
10B. What is the role of listeriolysin?
lysis of phagosome
II. Listeria monocytogenes
10C. What are the symptoms caused by Listeria monocytogenes?
- asymptomatic
- resembling mild flu
- meningitis
- skin infection – animal breeders
II. Listeria monocytogenes
11. How does immunity respond to Listeria monocytogenes?
- humoral immunity - unimportant (intracellular bacteria)
- patients with defects in cellular immunity, but
not in humoral immunity, are particularly susceptible to severe infections
II. Listeria monocytogenes
13. Explain epidemiology of Listeria monocytogenes
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
II. Listeria monocytogenes
14. What are the clinical diseases caused by Listeria monocytogenes
meningitis, sepsis, granulomatosis infantiseptica, endocarditis, GIT problems)
II. Listeria monocytogenes
15. Explain neonatal diseases caused by Listeria monocytogenes
- early onset disease - acquired transplacentally in utero
- Late-onset disease - acquired at or soon after birth
I. Listeria monocytogenes
16. Explain the clinical disease caused by Listeria monocytogenes in pregnant women
● 3rd trimester - cellular immunity is most impaired
● Infected women: nonspecific influenza symptoms – may resolve without treatment
I. Listeria monocytogenes
17. Explain the clinical disease caused by Listeria monocytogenes in healthy adults
● Most common → asymptomatic or mild influenza-like illness
● Acute, self-limited gastroenteritis (fever, headache, nausea, myalgias, and arthralgias)
I. Listeria monocytogenes
18. Explain Meningitis caused by Listeria monocytogenes in adults
● Most common form of disseminated listeriosis
● Listeria should be suspected in patients with organ transplants or cancer and in pregnant women
I. Listeria monocytogenes
19A. What is the Laboratory Diagnosis for Listeria monocytogenes
- Microscopy
- Serology
I. Listeria monocytogenes
19B. How do we do microscopy in Laboratory Diagnosis for Listeria monocytogenes
- Gram-stain: cerebrospinal fluid usually negative
- Gram-stain shows intracellular and extracellular gram- positive coccobacilli
II. Listeria monocytogenes
19C. How do we do serology in Laboratory Diagnosis for Listeria monocytogenes
- 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
II. Listeria monocytogenes
20. How do we treat Listeria monocytogenes?
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
II. Listeria monocytogenes
21. Do we have vaccine for Listeria monocytogenes?
vaccine is not available
