Podcast
Questions and Answers
What are the general characteristics of Staphylococcus?
What are the general characteristics of Staphylococcus?
Staphylococcus is a motile organism.
Staphylococcus is a motile organism.
False
What is Protein A known for in Staphylococcus?
What is Protein A known for in Staphylococcus?
Antiphagocytic
Which of the following is a virulence factor of Staphylococcus?
Which of the following is a virulence factor of Staphylococcus?
Signup and view all the answers
What skin lesion is characterized by a change in color and is flat?
What skin lesion is characterized by a change in color and is flat?
Signup and view all the answers
What is a characteristic of a pustule?
What is a characteristic of a pustule?
Signup and view all the answers
Staphylococcus aureus can cause __________, characterized by small, superficial abscesses.
Staphylococcus aureus can cause __________, characterized by small, superficial abscesses.
Signup and view all the answers
What syndrome is caused by exfoliative toxin in Staphylococcus?
What syndrome is caused by exfoliative toxin in Staphylococcus?
Signup and view all the answers
Which Staphylococcus species is associated with urinary tract infections?
Which Staphylococcus species is associated with urinary tract infections?
Signup and view all the answers
Toxic shock syndrome is common in menstruating women due to tampon use.
Toxic shock syndrome is common in menstruating women due to tampon use.
Signup and view all the answers
What is the short incubation period for Staphylococcal gastroenteritis?
What is the short incubation period for Staphylococcal gastroenteritis?
Signup and view all the answers
Study Notes
General Characteristics
- Staphylococcus is a Gram-positive bacterium with spherical cells arranged in grape-like clusters.
- Commonly found on skin and mucous membranes; it is non-motile and non-spore forming.
- Facultative anaerobes, capable of aerobic and anaerobic respiration, and active fermenters.
- Colonies produce pigments resulting in white to deep yellow appearances.
- Known for easily acquiring antibiotic resistance and producing catalase, differentiating it from Streptococci, which are catalase negative.
Virulence Factors
-
Cell Wall Components:
- Protein A: Anti-phagocytic, helps evade immune response.
- Fibronectin-binding protein (PnBP): Promotes adhesion to tissues.
-
Exotoxins:
- Cytolytic exotoxins like hemolysin can lyse red blood cells.
- Superantigen exotoxins heighten T lymphocyte activity, including enterotoxins and toxic shock syndrome toxin.
- Exfoliative toxin leads to scalded skin syndrome.
-
Enzymatic Factors:
- Coagulase: Clots plasma, aiding in localizing infection.
- Catalase: Converts hydrogen peroxide to water and oxygen.
- Other enzymes include hyaluronidase, staphylokinase, lipases, and nucleases which facilitate spreading.
Types of Skin Lesions
- Macules: Flat, discolored lesions.
- Papules: Raised lesions, solid, <5 mm in diameter.
- Plaques: Elevated flat lesions, >5 mm in diameter.
- Nodules: Rounded raised lesions, >5 mm in diameter.
- Urticaria: Pinkish annular papules or plaques, also known as hives.
- Vesicles: Fluid-filled lesions, <5 mm in diameter.
- Bullae: Larger fluid-filled lesions, >5 mm in diameter.
- Pustules: Lesions filled with exudate.
-
Purpura: Skin bleeds resulting in:
- Petechiae: <3 mm.
- Ecchymosis: >3 mm.
- Ulcer: Crater-like lesions affecting deeper skin layers.
- Eschar: Necrotic ulcer covered with blackened scab.
Staphylococcus aureus Pathology
-
Localized Skin Infections:
- STY: Small abscesses around hair follicles or glands.
- FURUNCLES/BOILS: Subcutaneous abscesses, often secondary to foreign bodies.
- CARBUNCLE: Deep, multiloculated infections that can spread systemically.
- IMPETIGO: Superficial, spreading crusted lesions.
- Staphylococcal scalded skin syndrome (Ritter’s disease): Common in infants; characterized by perioral erythema, Nikolsky sign, blistering, and desquamation.
Complications of Staphylococcus aureus
- Localized infections may lead to:
- Osteomyelitis (bone infection).
- Arthritis.
- Acute endocarditis (infection of heart valves).
- Septicemia (blood infection).
- Pneumonia and potential empyema (lung abscess).
Toxic Shock Syndrome
- Associated with tampons in menstruating women (first identified in the 1970s).
- Symptoms include fever, vomiting, diarrhea, hypotension, rash, and multi-organ involvement.
Staphylococcal Gastroenteritis
- Symptoms involve nausea, vomiting, and diarrhea without fever, with a quick onset (30 minutes to 8 hours post-exposure).
Coagulase Negative Staphylococcus
- Staphylococcus epidermidis: Infects prosthetic devices.
- Staphylococcus saprophyticus: Common cause of urinary tract infections.
Epidemiology
- Staphylococcus species are ubiquitous in the environment.
- Transmission occurs through droplets and drainage from lesions.
- Hygiene, cleanliness, and aseptic management are vital for control, alongside methods like aerosols, ultraviolet irradiation, and antiseptics.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the general characteristics and virulence factors of Staphylococcus, focusing on its structure, growth conditions, and antibiotic resistance. It highlights unique features like Protein A and the significance of catalase production. Test your knowledge about this important bacterial genus.
