Textbook Question
Mycobacterium avium-intracellulare was considered relatively harmless until the late 20th century, when it became common in certain infections. Explain how this bacterium’s pathogenicity changed.
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Ch. 19 - Pathogenic Gram-Positive Bacteria
Bauman6th EditionMicrobiology with Diseases by TaxonomyISBN: 9780134832302
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Table of contents
- Ch. 1 - A Brief History of Microbiology31
- Ch. 2 - The Chemistry of Microbiology28
- Ch. 3 - Cell Structure and Function39
- Ch. 4 - Microscopy, Staining, and Classification25
- Ch. 5 - Microbial Metabolism51
- Ch. 6 - Microbial Nutrition and Growth37
- Ch. 7 - Microbial Genetics51
- Ch. 8 - Recombinant DNA Technology21
- Ch. 9 - Controlling Microbial Growth in the Environment36
- Ch. 10 - Controlling Microbial Growth in the Body: Antimicrobial Drugs21
- Ch. 11 - Characterizing and Classifying Prokaryotes29
- Ch. 12 - Characterizing and Classifying Eukaryotes34
- Ch. 13 - Characterizing and Classifying Viruses, Viroids, and Prions23
- Ch. 14 - Infection, Infectious Diseases, and Epidemiology35
- Ch. 15 - Innate Immunity34
- Ch. 16 - Adaptive Immunity21
- Ch. 17 - Immunization and Immune Testing29
- Ch. 18 - Immune Disorders22
- Ch. 19 - Pathogenic Gram-Positive Bacteria25
- Ch. 20 - Pathogenic Gram-Negative Cocci and Bacilli28
- Ch. 21 - Rickettsias, Chlamydias, Spirochetes, and Vibrios25
- Ch. 22 - Pathogenic Fungi47
- Ch. 23 - Parasitic Protozoa, Helminths, and Arthropod Vectors44
- Ch. 24 - Pathogenic DNA Viruses23
- Ch. 25 - Pathogenic RNA Viruses30
- Ch. 26 - Applied and Industrial Microbiology29
- Ch. 27 - Microbial Ecology and Microbiomes22
Bauman6th EditionMicrobiology with Diseases by TaxonomyISBN: 9780134832302Not the one you use?Change textbook
Chapter 19, Problem 2
How does Staphylococcus aureus affect the matrix between cells in the human body?
a. S. aureus triggers blood clotting, which coats the matrix and inhibits cellular
communication.
b. S. aureus produces an enzyme that dissolves hyaluronic acid and thus enables it to pass between the cells.
c. S. aureus possesses a hyaluronic acid capsule that causes leukocytes to ignore the bacterium as if it were camouflaged.
d. S. aureus does not affect the matrix but instead produces a necrotizing agent that dissolves body cells.
Verified step by step guidance1
Understand that the extracellular matrix (ECM) between cells is composed of various substances, including hyaluronic acid, which helps maintain tissue structure and acts as a barrier to pathogens.
Recognize that some bacteria produce enzymes called hyaluronidases, which break down hyaluronic acid in the ECM, allowing the bacteria to spread through tissues more easily.
Recall that Staphylococcus aureus is known to produce such an enzyme, hyaluronidase, which degrades hyaluronic acid and facilitates bacterial movement between cells.
Evaluate the answer choices by matching this knowledge: the option describing S. aureus producing an enzyme that dissolves hyaluronic acid aligns with its mechanism to penetrate the matrix.
Conclude that the correct understanding is that S. aureus affects the matrix by producing an enzyme that breaks down hyaluronic acid, enabling it to pass between cells.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Extracellular Matrix and Hyaluronic Acid
The extracellular matrix (ECM) is a network of molecules like proteins and polysaccharides, including hyaluronic acid, that provide structural support between cells. Hyaluronic acid helps maintain tissue hydration and acts as a barrier to microbial invasion. Some bacteria produce enzymes that degrade hyaluronic acid to penetrate tissues.
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Hyaluronidase Enzyme Produced by Staphylococcus aureus
Staphylococcus aureus secretes hyaluronidase, an enzyme that breaks down hyaluronic acid in the ECM. This degradation allows the bacteria to spread more easily between cells by disrupting the matrix, facilitating tissue invasion and infection progression.
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03:48Environmental Factors Affecting Enzyme Activity
Bacterial Evasion of Host Immune Response
S. aureus can evade immune detection using mechanisms like a hyaluronic acid capsule that mimics host tissues, helping it avoid leukocyte attack. This camouflage allows the bacteria to persist in the host by reducing immune system recognition and clearance.
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Related Practice
Textbook Question
Why are mycoplasmas able to survive a relatively wide range of osmotic conditions, even though these bacteria lack cell walls?
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Textbook Question
Which of the following conditions is a systemic disease caused by Staphylococcus?
a. Impetigo
b. Folliculitis
c. Carbuncle
d. Toxic shock syndrome
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Textbook Question
Which of the following bacteria causes a common type of food poisoning?
a. Streptococcus sanguis
b. Clostridium tetani
c. Staphylococcus aureus
d. Streptococcus pyogenes
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Textbook Question
Label acetylcholine. Color the sites of action of botulism toxin on a nerve cell.
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Textbook Question
Match the genera of pathogens to their appearance in stained smears: Actinomyces, Bacillus, Clostridium, Mycobacterium, Staphylococcus, Streptococcus.
(a) Methenamine silver <IMAGE>
(b) Gram <IMAGE>
(c) Gram <IMAGE>
(d) Acid fast <IMAGE>
(e) Gram <IMAGE>
(f) Gram <IMAGE>
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