Intro to Microbiology & Infectious Diseases

Question 1

Explain the historical changes in the significance of infectious diseases in medicine

Answer 1

• infectious diseases decline due to improved nutrition, antibiotics, and vaccinations
• infectious diseases increase due to changing ethics concerning sex, drug abuse, & food choice; travel; medicine such as immunosuppressive therapy and transplants
• zoonotic pathogens come about through increased interactions with animals

Question 2

Compare and contrast the distinctive features of prokaryotic and eukaryotic cells

Answer 2

Eukaryotic: nucleus, membranous compartments, liner DNA, multiple copies, larger
Prokaryotic: no nucleus, no membrane-bound organelles, 1 circular DNA, 1000x smaller

Question 3

Differentiate the major classes of microorganisms: viruses, bacteria, fungi, and parasites

Answer 3

Viruses: piece of genetic information capable of copying itself using cellular machines, packaging itself, and transmitting between cells
Bacteria: unicellular prokaryotes
Fungi: multicellular eukaryotes, immotile, nonphotosynthetic
Parasites: organism that feeds off of another organism

Question 4

Explain symbiosis, amensalism, commensalism, mutualism, and parasitism

Answer 4

Symbiosis: the relationship between organisms living together
Amensalism: 1 hurts, the other is unaffected
Commensalism: 1 benefits, the other is unaffected
Mutualism: both benefit
Parasitism: 1 benefits, the other hurts

Question 5

Describe major anatomical sites that are rich in normal flora

Answer 5

skin: Staphylococcus epidermidis, Propionibacterium acnes
saliva: Streptococcus mutans and Streptococcus salivarius
colon: Escherichia coli, but most are anaerobes
vagina: E. Coli (prepubescent and postmenopausal) and lactobacilli (reproductove age)

Question 6

Explain factors that affect the vaginal flora

Answer 6

• reproductive timing
• insufficient lactobacillus causes overgrowth of other bacteria - UTI and bacterial vaginosis
• too much estrogen/carbohydrate - candida albicans take over (vaginal thrush)

Question 7

Describe the characteristics of microparasites and macroparasites

Answer 7

microparasites: can multiply in 1 host
macroparasites: cannot multiply in 1 host

Question 8

Explain the host conditions that may turn normal flora to pathogens

Answer 8

changed location

compromised host defense (floral imbalance)

Question 9

Explain Koch’s postulates

Answer 9

• microbe must be present in every case
• microbe must be isolated from host and cultured.
• microbe must cause disease when introduced to a host organism
• microbe must be isolated from the inoculated host

Question 10

What happens when too much estrogen is released in reproductive women?

Answer 10

vaginal thrush