Textbook Question
Use the following choices to answer questions 8–10:
a. Apicomplexa
b. Ciliates
c. Dinoflagellates
d. Microsporidia
These are nonmotile parasites with special organelles for penetrating host tissue.
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Ch. 21 - Microbial Diseases of the Skin and Eyes
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398
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Table of contents
- Ch. 1 - The Microbial World and You18
- Ch. 2 - Chemical Principles20
- Ch. 3 - Observing Microorganisms Through a Microscope18
- Ch. 4 - Functional Anatomy of Prokaryotic and Eukaryotic Cells21
- Ch. 5 - Microbial Metabolism20
- Ch. 6 - Microbial Growth20
- Ch. 7 - The Control of Microbial Growth20
- Ch. 8 - Microbial Genetics19
- Ch. 9 - Biotechnology & DNA Technology20
- Ch. 10 - Classification of Microorganisms15
- Ch. 11 - The Prokaryotes: Domains Bacteria and Archaea14
- Ch. 12 - The Eukaryotes: Fungi, Algae, Protozoa, and Helminths17
- Ch. 13 - Viruses, Viroids, and Prions20
- Ch. 14 - Principles of Disease and Epidemiology21
- Ch. 15 - Microbial Mechanisms of Pathogenicity19
- Ch. 16 - Innate Immunity: Nonspecific Defenses of the Host20
- Ch. 17 - Adaptive Immunity: Specific Defenses of the Host20
- Ch. 18 - Practical Applications of Immunology20
- Ch. 19 - Disorders Associated with the Immune System19
- Ch. 20 - Antimicrobial Drugs19
- Ch. 21 - Microbial Diseases of the Skin and Eyes21
- Ch. 22 - Microbial Diseases of the Nervous System19
- Ch. 23 - Microbial Diseases of the Cardiovascular and Lymphatic Systems20
- Ch. 24 - Microbial Diseases of the Respiratory System20
- Ch. 25 - Microbial Diseases of the Digestive System20
- Ch. 26 - Microbial Diseases of the Urinary and Reproductive Systems19
- Ch. 27 - Environmental Microbiology20
- Ch. 28 - Applied and Industrial Microbiology19
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook
Chapter 21, Problem 8
Use the following choices to answer the question given below.
a. Pseudomonas
b. Staphylococcus aureus
c. Scabies
d. Sporothrix
e. Virus
Microscopic examination of the patient’s ulcer reveals 10μm ovoid cells.
Verified step by step guidance1
Step 1: Identify the size and shape of the cells observed under the microscope. The problem states the cells are ovoid and approximately 10μm in size.
Step 2: Recall the typical size ranges and shapes of the organisms listed in the choices: Pseudomonas (bacteria, usually smaller than 5μm), Staphylococcus aureus (cocci bacteria, about 1μm), scabies (a mite, much larger than 10μm), Sporothrix (a fungus with yeast-like ovoid cells around 3-10μm), and viruses (much smaller than 1μm).
Step 3: Compare the observed cell size and shape to the known characteristics of each organism. Since the cells are ovoid and about 10μm, this size fits best with fungal yeast cells like Sporothrix.
Step 4: Exclude options that do not match the microscopic features: bacteria and viruses are too small, and scabies is a mite, which is much larger and not described as ovoid cells.
Step 5: Conclude that the microscopic description most likely corresponds to Sporothrix, a dimorphic fungus known to produce ovoid yeast cells of this size in tissue.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Microscopic Cell Morphology
Understanding the size and shape of cells under the microscope is crucial for identifying microorganisms. Ovoid cells measuring around 10μm suggest a eukaryotic organism, as most bacteria are smaller (1-5μm). This helps differentiate between bacteria, fungi, and other pathogens.
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02:44
Types of Bacterial Cell Morphology
Characteristics of Common Pathogens
Familiarity with the typical features of pathogens like Pseudomonas, Staphylococcus aureus, Sporothrix, viruses, and scabies is essential. For example, Sporothrix is a fungus with ovoid yeast cells about 10μm, while bacteria and viruses differ in size and morphology.
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Diagnostic Relevance of Ulcer Examination
Examining ulcers microscopically helps identify the causative agent by revealing cell type and morphology. This guides diagnosis and treatment, as different pathogens require specific therapies, making microscopic findings a key diagnostic tool.
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Related Practice
Textbook Question
Use the following choices to answer the question given below.
a. Pseudomonas
b. Staphylococcus aureus
c. Scabies
d. Sporothrix
e. Virus
Microscopic examination of scrapings from the patient’s rash shows gram-negative rods.
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Textbook Question
Use the following choices to answer the question given below.
a. Pseudomonas
b. Staphylococcus aureus
c. Scabies
d. Sporothrix
e. Virus
Nothing is seen in microscopic examination of a scraping from the patient’s rash.
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Textbook Question
What is in the MMR vaccine?
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Textbook Question
A patient exhibits inflammatory skin lesions that itch intensely. Microscopic examination of skin scrapings reveals an eight-legged arthropod. What is your diagnosis? How is the disease treated? What would you conclude if you saw a six-legged arthropod?
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Textbook Question
What complications can occur from HSV-1 infections?
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