Textbook Question
Shown is a MacConkey agar plate. Describe the Gram reaction and lactose fermentation of the two different bacteria shown.
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Ch. 20 - Pathogenic Gram-Negative Cocci and Bacilli
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 20, Problem 3
Which of the following bacterial cells is most likely to be virulent?
a. A cell with fimbriae and LOS
b. A cell with a polysaccharide capsule and lipooligosaccharide
c. A cell with fimbriae, lipooligosaccharide, and a polysaccharide capsule
d. A cell with fimbriae but no capsule
Verified step by step guidance1
Step 1: Understand the key virulence factors mentioned in the options: fimbriae, lipooligosaccharide (LOS), and polysaccharide capsule. Each of these contributes differently to bacterial pathogenicity.
Step 2: Recall that fimbriae help bacteria adhere to host cells, which is important for colonization but alone may not confer high virulence.
Step 3: Recognize that lipooligosaccharide (LOS) is an endotoxin found in the outer membrane of some Gram-negative bacteria, contributing to immune evasion and inflammation.
Step 4: Know that a polysaccharide capsule protects bacteria from phagocytosis by host immune cells, significantly enhancing virulence.
Step 5: Compare the options by combining these factors: the most virulent bacterial cell is likely the one possessing fimbriae (for adhesion), LOS (for immune interaction), and a polysaccharide capsule (for protection), which corresponds to option c.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Virulence Factors in Bacteria
Virulence factors are molecules produced by bacteria that enhance their ability to cause disease. These include structures like fimbriae for attachment, capsules for evading immune responses, and components like lipooligosaccharide that trigger inflammation. Understanding these factors helps determine which bacterial cells are more likely to be virulent.
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Virulence
Polysaccharide Capsule
A polysaccharide capsule is a protective layer surrounding some bacterial cells that helps them evade phagocytosis by host immune cells. This capsule increases bacterial survival in the host and is often associated with increased virulence, making bacteria more resistant to immune defenses.
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Lipooligosaccharide (LOS)
Lipooligosaccharide is a component of the outer membrane of certain Gram-negative bacteria, similar to lipopolysaccharide but with a shorter polysaccharide chain. LOS can trigger strong immune responses and contribute to bacterial pathogenicity by inducing inflammation and damaging host tissues.
Related Practice
Textbook Question
The only genus of Gram-negative cocci that causes significant disease in humans is
a. Pasteurella
b. Salmonella
c. Klebsiella
d. Neisseria
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Textbook Question
Why do nurses place antimicrobial agents in babies’ eyes at birth?
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Textbook Question
Statistics show that meningococcal diseases are more frequent in college dormitories and military barracks than in the population at large. Suggest an explanation of this observation.
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Textbook Question
Which of the following statements is true?
a. PID is a severe type of diarrhea in which infection spreads from the intestines to
the bloodstream.
b. PID can result from Neisseria infection.
c. PID is more common in men than women.
d. Members of the family Enterobacteriaceae usually cause PID.
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Textbook Question
Distinguish among the pathogenicity of coliforms, noncoliforms, and truly pathogenic enteric bacteria.
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