Textbook Question
Identify the diseases based on the symptoms in the following chart.
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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 6
You microscopically examine scrapings from a case of Acanthamoeba keratitis. You expect to see
a. Nothing.
b. Viruses.
c. Gram-positive cocci.
d. Eukaryotic cells.
e. Gram-negative cocci.
Verified step by step guidance1
Step 1: Understand the organism involved. Acanthamoeba is a genus of free-living amoebae, which are eukaryotic protozoa, not bacteria or viruses.
Step 2: Recall the characteristics of eukaryotic cells. They have a defined nucleus and other membrane-bound organelles, which can be seen under a microscope when examining scrapings.
Step 3: Consider what you would expect to see microscopically in a case of Acanthamoeba keratitis. Since Acanthamoeba is a eukaryote, you would expect to see eukaryotic cells rather than bacteria (which are prokaryotic) or viruses (which are not visible by light microscopy).
Step 4: Eliminate options that do not fit. Viruses are too small to be seen with a light microscope, and gram-positive or gram-negative cocci are types of bacteria, which are not the causative agent here.
Step 5: Conclude that the correct microscopic observation would be eukaryotic cells, consistent with the presence of Acanthamoeba.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acanthamoeba Biology
Acanthamoeba is a genus of free-living amoebae that are eukaryotic microorganisms. They have a nucleus and membrane-bound organelles, distinguishing them from bacteria and viruses. Acanthamoeba can cause keratitis, an infection of the cornea, especially in contact lens users.
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Basic Theories of Biology
Microscopic Identification of Microorganisms
Microscopic examination helps differentiate microorganisms based on size, structure, and staining properties. Eukaryotic cells like Acanthamoeba are larger and have visible nuclei, unlike bacteria which are smaller and prokaryotic. Viruses are too small to be seen with a light microscope.
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Gram Staining and Microbial Classification
Gram staining differentiates bacteria into gram-positive (purple) and gram-negative (pink) based on cell wall structure. Cocci refer to spherical bacteria. Since Acanthamoeba is a eukaryote, it does not stain with Gram stain and is not classified as gram-positive or gram-negative cocci.
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Related Practice
Textbook Question
A patient has conjunctivitis. If you isolated Pseudomonas from the patient’s mascara, you would most likely conclude all of the following except that
a. The mascara was the source of the infection.
b. Pseudomonas is causing the infection.
c. Pseudomonas has been growing in the mascara.
d. The mascara was contaminated by the manufacturer.
e. All of the above are valid conclusions.
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Textbook Question
Before 2005, why was a test for antibodies against rubella required for females under age 50 before issuing a marriage license?
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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 complications can occur from HSV-1 infections?
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Textbook Question
A 12-year old boy had a fever, rash, headache, sore throat, and cough. He also had a macular rash on his trunk, face, and arms. A throat culture was negative for Streptococcus pyogenes.
All of the following are complications of this disease except
a. Middle ear infections.
b. Pneumonia.
c. Birth defects.
d. Encephalitis.
e. All are complications of this disease.
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