Skin Infections Types
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Questions and Answers

What is the main difference between coagulase-negative Staphylococcus epidermidis and coagulase-positive S. aureus?

  • Coagulase-positive is less virulent
  • Coagulase-positive can enter the body through natural openings (correct)
  • Coagulase-negative is more pathogenic
  • Coagulase-negative is more resistant to antibiotics
  • Which of the following is a type of acne characterized by inflammatory papules and pustules?

  • Impetigo
  • Seborrheic dermatitis
  • Folliculitis
  • Acne vulgaris (correct)
  • What is the primary mode of transmission of impetigo?

  • Airborne transmission
  • Vector-borne transmission
  • Direct contact (correct)
  • Contaminated food and water
  • Which of the following bacteria is commonly associated with streptococcal skin infections?

    <p>Streptococcus pyogenes</p> Signup and view all the answers

    What is the name of the yeast that is associated with the scaling skin condition known as dandruff?

    <p>Malassezia furfur</p> Signup and view all the answers

    What is the name of the bacteria that produces propionic acid, which helps maintain the low pH of the skin?

    <p>Propionibacterium acnes</p> Signup and view all the answers

    What is the primary route of entry for the pathogen that causes impetigo?

    <p>Through minor breaks in the skin</p> Signup and view all the answers

    What is the characteristic of bullous impetigo?

    <p>It is a form of staphylococcal scalded skin syndrome</p> Signup and view all the answers

    What is the primary cause of inflammatory acne?

    <p>Infection by Propionibacterium acnes</p> Signup and view all the answers

    What is the characteristic of erysipelas, a type of streptococcal skin infection?

    <p>It can cause sepsis</p> Signup and view all the answers

    What is the primary cause of viral warts?

    <p>Papillomavirus</p> Signup and view all the answers

    What is the characteristic of nodular cystic acne?

    <p>It is a severe form of acne that leaves scars</p> Signup and view all the answers

    How does the tetanus neurotoxin affect the muscles?

    <p>It causes muscle spasms</p> Signup and view all the answers

    What is the primary mode of transmission for poliomyelitis?

    <p>Ingestion</p> Signup and view all the answers

    What type of bacteria causes botulism?

    <p>Obligately anaerobic</p> Signup and view all the answers

    What is the effect of the botulinal toxin on the nervous system?

    <p>It blocks the release of acetylcholine</p> Signup and view all the answers

    What is the characteristic symptom of tetanus?

    <p>Muscle spasms</p> Signup and view all the answers

    What is the prevention method for tetanus?

    <p>Vaccination</p> Signup and view all the answers

    What is the mortality rate of Haemophilus influenzae Meningitis?

    <p>6%</p> Signup and view all the answers

    Which of the following bacteria is a gram-positive, encapsulated diplococcus?

    <p>Streptococcus pneumoniae</p> Signup and view all the answers

    What is the mode of transmission for Neisseria meningitidis Meningitis?

    <p>Droplet aerosols or direct contact with secretions</p> Signup and view all the answers

    What is the primary habitat of Listeria monocytogenes?

    <p>Soil and water</p> Signup and view all the answers

    Which of the following is a common inhabitant of the nasopharyngeal region?

    <p>Streptococcus pneumoniae</p> Signup and view all the answers

    What is the primary treatment for Neisseria meningitidis Meningitis?

    <p>Penicillin and cephalosporins</p> Signup and view all the answers

    What is the primary characteristic of Listeria monocytogenes that allows it to grow at low temperatures?

    <p>Psychrotrophic</p> Signup and view all the answers

    Study Notes

    Bacterial Skin Infections

    • Staphylococcal skin infections:
      • Caused by Staphylococcus aureus, a coagulase-positive bacterium
      • Can enter the body through natural openings such as hair follicles and cause folliculitis or furuncles
      • Impetigo is a type of staphylococcal skin infection, mostly affecting children aged 2-5 years
      • Symptoms: fever, headache, stiff neck, nausea, and vomiting
      • Treatment: Cephalosporins, vancomycin
    • Streptococcal skin infections:
      • Caused by Streptococcus pyogenes, a Group A beta-hemolytic streptococcus
      • Can cause impetigo and erysipelas
      • Erysipelas can cause sepsis
      • Necrotizing fasciitis is a serious complication of streptococcal skin infections
      • Streptococcal toxic shock syndrome can cause bacteremia and organ damage

    Viral Skin Infections

    • Warts:
      • Caused by Papillomavirus
      • More than 50 types of papillomavirus can cause different types of warts
      • Incubation period: several weeks
      • Treatment: cryotherapy, electrodesiccation, and salicylic acid
    • Smallpox:
      • Caused by Orthopoxvirus
      • Variola major has a mortality rate of 20-60%, while variola minor has a mortality rate of less than 1%
      • Transmitted by the respiratory route
      • Eradicated in 1977 by vaccination
    • Chickenpox:
      • Caused by Varicellazoster virus (human herpesvirus 3)
      • Transmitted by the respiratory route
      • Causes pus-filled vesicles
      • Lesions on the face, lower back, chest, and shoulders
      • Prevention: Live attenuated vaccine
    • Herpes Simplex:
      • Caused by Human herpesvirus 1 (HSV-1) and 2 (HSV-2)
      • Causes cold sores and fever blisters
      • Herpes gladiatorum is a common manifestation among wrestlers
      • Herpes encephalitis can occur
      • HSV-1 can remain latent in trigeminal nerve ganglia

    Microbial Diseases of the Eye

    • Conjunctivitis:
      • Inflammation of the conjunctiva
      • Haemophilus influenzae is the most common bacterial cause
      • Viral conjunctivitis is usually caused by adenoviruses
      • Swimming pool conjunctivitis is caused by Chlamydia trachomatis
      • Trachoma is an eye infection caused by Chlamydia trachomatis
    • Herpetic Keratitis:
      • Caused by Herpes Simplex virus type 1
      • Acanthamoeba Keratitis is caused by an ameba found in fresh water, tap water, hot tubs, and soil

    Infectious Diseases of the Nervous System

    • Tetanus:
      • Caused by Clostridium tetani
      • Obligately anaerobic, endospore-forming, gram-positive rod
      • Growth in deep wounds
      • Prevention: vaccination
      • Treatment: tetanus immune globulin
    • Botulism:
      • Caused by Clostridium botulinum
      • Obligately anaerobic, endospore-forming, gram-positive rod
      • Found in soil and many aquatic sediments
      • Food poisoning occurs in anaerobic environments, such as sealed cans
      • Intoxication occurs from ingesting botulinal toxin
      • Toxin blocks release of neurotransmitter acetylcholine, causing flaccid paralysis
    • Poliomyelitis:
      • Caused by Poliovirus
      • Transmitted by ingestion
      • Initial symptoms: sore throat and nausea
      • Viremia may occur, and if persistent, the virus can enter the CNS and cause destruction of motor cells and paralysis

    Normal Microbiota of the Skin

    • The epidermis is the thin outer portion of the skin, composed of several layers of epithelial cells
    • The dermis is the inner, relatively thick portion of skin, composed mainly of connective tissue
    • Normal microbiota of the skin includes:
      • Staphylococcus epidermidis
      • Staphylococcus aureus
      • Micrococcus species
      • α-Hemolytic and nonhemolytic streptococci
      • Corynebacterium species
      • Propionibacterium species
      • Peptostreptococcus species
      • Acinetobacter species
      • Small numbers of other organisms (Candida species, Pseudomonas aeruginosa, etc.)

    Acne

    • Classification of acne:
      • Comedonal (mild) acne: caused by blocked sebum channels with shed cells
      • Inflammatory (moderate) acne: caused by Propionibacterium acnes
      • Nodular cystic (severe) acne: characterized by nodules or cysts filled with pus
    • Treatment of acne:
      • Azelaic acid
      • Salicylic acid preparations
      • Retinoids (derivatives of vitamin A)
      • Isotretinoin for severe acne

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    Description

    This quiz covers different types of skin infections, including impetigo and erysipelas, caused by staphylococcal and streptococcal toxins and bacteria.

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