FR4- Bacterial Growth

Question 1

What are facultative intracellulra pathogens?

Answer 1

• Those organisms that can reside within the cells of the host or in the environment.
• A bacterial example is Brucella abortus, which is capable of growth and replication within macrophages, neutrophils, and trophoblast cells.

Question 2

What are obligate intracellular pathogens?

Answer 2

• They are incapable of growth and multiplication outside a host cell. By definition, all viruses are obligate intracellular pathogens in that they require a host cell for replication, often to the detriment of that cell.
• Some bacteria are also obligate intracellular bacterial pathogens, such as Chlamydia spp

Question 3

What is the presence of viable bacteria in the bloodstream called?

Answer 3

bacteremia

Question 4

What ia the infectious disease process caused by bacterial or fungal toxins in the blood termed?

Answer 4

septicemia

Question 5

Why is Clostridium tetani (the cause of tetanus) considered noninvasive?

Answer 5

It does not spread from one tissue to anothe

Question 6

Give examples of Bacterial Virulence Factors Involved in Bacterial Pathogen Invasion and Dissemination

Answer 6

Question 7

Give examples of well known disease causing bacteria

Answer 7

• Clostridium tetani (the cause of tetanus) is considered noninvasive because it does not spread from one tissue to another, but its toxin becomes blood-borne, thereby causing disease.
• Bacillus anthracis (the cause of anthrax) and Yersinia pestis (the cause of plague) also produce toxins but the bacteria are also highly invasive.
• Microsporidia spp. use a novel polar tubule to bore into host cells whereas many other fungi use hydrolytic enzymes to invade cells and tissues

Question 8

Explain the properties of exotoxins

Answer 8

• Exotoxins are soluble, heat-labile proteins (inactivated at 60 to 80°C) that usually are released into the surroundings as the bacterial pathogen grows.
• Often exotoxins travel from the site of infection to other body tissues or target cells, where they exert their effects.
• Exotoxins are often encoded by genes carried on plasmids or prophages carried by specific bacteria.
• They are associated with specific diseases and often are named for the disease they produce (e.g., the diphtheria toxin). Some are among the most lethal substances known— toxic in nanogram-per-kilogram of body weight concentrations (e.g., botulinum toxin).

Question 9

How do exotoxins exert their biological activity?