Podcast
Questions and Answers
Which virulence factor of Neisseria gonorrhoeae is responsible for mediating firm attachment to epithelial cells?
Which virulence factor of Neisseria gonorrhoeae is responsible for mediating firm attachment to epithelial cells?
What is the role of Rmp (reduction-modifiable protein) in the virulence of Neisseria gonorrhoeae?
What is the role of Rmp (reduction-modifiable protein) in the virulence of Neisseria gonorrhoeae?
How does the lipooligosaccharide (LOS) of Neisseria gonorrhoeae contribute to its pathogenesis?
How does the lipooligosaccharide (LOS) of Neisseria gonorrhoeae contribute to its pathogenesis?
Which of the following factors does NOT contribute to the high reinfection rates of gonorrhea?
Which of the following factors does NOT contribute to the high reinfection rates of gonorrhea?
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What mechanism allows Neisseria gonorrhoeae to inhibit the entry of certain antibiotics?
What mechanism allows Neisseria gonorrhoeae to inhibit the entry of certain antibiotics?
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What is the primary risk factor associated with Toxic Shock Syndrome Toxin-1 (TSST-1)?
What is the primary risk factor associated with Toxic Shock Syndrome Toxin-1 (TSST-1)?
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Which of the following statements about enterotoxins produced by Staphylococcus aureus is correct?
Which of the following statements about enterotoxins produced by Staphylococcus aureus is correct?
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Which of the following conditions can lead to a higher rate of S. aureus colonization?
Which of the following conditions can lead to a higher rate of S. aureus colonization?
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What is a symptom that occurs 10 days after the initial onset of TSST-1?
What is a symptom that occurs 10 days after the initial onset of TSST-1?
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Which factor explains why certain occupations are more prone to S. aureus colonization?
Which factor explains why certain occupations are more prone to S. aureus colonization?
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Which of the following components of Streptococcus pyogenes contributes to its avoidance of phagocytosis?
Which of the following components of Streptococcus pyogenes contributes to its avoidance of phagocytosis?
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Which virulence factor is responsible for the hemolytic activity of Streptococcus pyogenes?
Which virulence factor is responsible for the hemolytic activity of Streptococcus pyogenes?
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What type of hemolysis is characterized by a complete disruption of red blood cells and a clear zone around colonies?
What type of hemolysis is characterized by a complete disruption of red blood cells and a clear zone around colonies?
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Which of the following is NOT a characteristic of streptococcal toxic shock syndrome?
Which of the following is NOT a characteristic of streptococcal toxic shock syndrome?
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Which group of Streptococcus is now classified as Enterococci?
Which group of Streptococcus is now classified as Enterococci?
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Which of the following streptococcal virulence factors are known as erythrogenic toxins?
Which of the following streptococcal virulence factors are known as erythrogenic toxins?
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Which of the following statements about Streptococcus pneumoniae, an alpha-hemolytic streptococcus, is true?
Which of the following statements about Streptococcus pneumoniae, an alpha-hemolytic streptococcus, is true?
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Streptokinases produced by Streptococcus pyogenes are responsible for what function?
Streptokinases produced by Streptococcus pyogenes are responsible for what function?
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Study Notes
Neisseria Gonorrhoeae
- Only fimbriated cells are virulent
- Por protein prevents phagolysosome fusion and promotes intracellular survival
- Opa protein mediates attachment to epithelial cells and invasion
- Rmp protein protects surface antigens from antibodies
Gonococcal Virulence Factors II
- Tbp 1 and Tbp 2 bind transferrin
- Lbp binds lactoferrin
- Hbp binds hemoglobin
- LOS retains endotoxin activity
- IgA1 protease degrades IgA antibodies
- Antibiotic resistance
- Plasmid-encoded beta-lactamase production
- Chromosomally-mediated changes in cellular permeability
Epidemiology of Gonorrhea
- Transmitted sexually
- Asymptomatic carriers are the major reservoir
- Lack of protective immunity leads to reinfection due to antigenic diversity
- Higher risk of disseminated disease in individuals with complement deficiencies
Pathogenesis of N. aureus: Secretion of Toxins II
- Toxic Shock Syndrome Toxin-1 (TSST-1) is associated with vaginal tampon use
- Ultra-absorbent tampons bind Mg2+ ions
- Low Mg2+ triggers TSST-1 production by vaginal Staphylococci
- TSST-1 stimulates IL-1 production by macrophages, leading to endothelial cell extravasation and fever
- Initial symptoms: high fever, vomiting, diarrhea, myalgia, hypovolemic shock, and multiorgan failure
- 10 days after onset: sunburn-like rash on hands and soles of feet with skin peeling
- Shock caused by hypotension
- Death due to respiratory failure in 2-5% of cases
Virulence Factors of S. aureus: Secretion of Toxins III
- Eight enterotoxins (A-E, G-I) are resistant to gastric and jejunal enzymes
- Enterotoxins are stable at 100ºC for 30 minutes
- Mechanism of enterotoxin activity is not fully understood
- Enterotoxins stimulate intestinal peristalsis and affect the central nervous system, causing vomiting
Epidemiology of S. aureus
- Humans are the major reservoir for S. aureus
- S. aureus colonizes the nose in about 30% of individuals
- S. aureus is found transiently on the skin, oropharynx, and feces
- Transmitted via hand contact and aerosols
- Healthcare workers and individuals with certain medical conditions (diabetes, hemodialysis, drug abuse, HIV) are more prone to colonization
Pathogenesis of S. Hemolysis
- Alpha hemolysis: oxidation of iron in haemoglobin, greenish color
- Beta hemolysis: complete disruption of red cells, clear zone around colonies
- Gamma hemolysis: non-hemolytic streptococci
Streptococci Relevant in Human Disease
- Alpha hemolytic: Streptococcus pneumonia
- Beta hemolytic:
- Group A: Streptococcus pyogenes
- Group B: Streptococcus agalactiae
- Group C
- Group F
- Group G
- Non-hemolytic: Group D (now Enterococci)
Streptococcus pyogenes
- Capsule, M protein, F protein, and lipoteichoic acid help avoid phagocytosis
Virulence Factors of Streptococcus pyogenes II
- Streptolysin O (O2 labile) causes hemolysis of red blood cells, leukocytes, and platelets
- Streptolysin S (O2 stable) causes hemolysis of red blood cells, leukocytes, platelets, and other cells
- Streptococcal pyrogenic exotoxins (A, B, C, and F) are also known as erythrogenic toxins, causing the characteristic red rash in scarlet fever and shock in streptococcal toxic shock syndrome
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Description
This quiz covers the virulence factors of Neisseria gonorrhoeae, including critical proteins involved in pathogenesis and survival. It also explores the epidemiology of gonorrhea and the factors influencing antibiotic resistance. Test your knowledge on this significant pathogen and its implications for human health.
