Portage Learning BIOD 171 Module 5
Exam Module 5
1. Define the concept of universal precautions.
Universal precautions means any and all samples,
... [Show More] whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials.
2. List at least 3 observations a researcher would be sure to note while assessing an unknown microbial sample.
A lab researcher would be certain to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
4. The presence of any chemical reactions
5. Changes in color localized to the organism or the surrounding media
6. Capture (or draw) images of any of the characteristics described above
3. While observing an unknown sample of limited amounts, a researcher must determine the following observations: (1) the presence of any motility and (2) its Gram status using the same sample—the liquid sample cannot be divided. Which would you determine first and why?
You must determine motility before determining the Gram status. Motility requires a wet mount, while Gram staining requires heat fixing the sample. If one were to begin with the Gram stain the heat fixation process would kill the organism, making any observations regarding motility impossible. The correct approach would be to place the liquid culture on a glass slide and determine its motility status. Next, the same liquid culture can be heat fixed and Gram stained.
4. A facultative anaerobe is a microorganism capable of growth under what conditions?
A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic (without oxygen) conditions.
5. True or False. The Lancefield groups are used to subdivide antigenic groups of alpha-hemolytic Streptococcus.
False. The Lancefield groupings are used to subdivide beta-hemolytic Strep.
6. The distinctions for Lancefield subgroupings lie in its: (select all that apply)
A. Catalase activity
B. Carbohydrate composition of antigens
C. Hemolytic activity
D. All of the above
B. Carbohydrate composition of antigens present in the cell wall determines the Lancefield groupings (A, B, C, etc). Note, ALL strep under Lancefield groupings are (by definition) catalase negative and beta-hemolytic. Thus, answers A and C cannot be used to subdivide streptococcal species.
7. Rheumatic fever displays hemolytic activity and occurs when is left untreated.
A. Beta; Strep. Pharyngitis
B. Gamma; Strep. Septicemia
C. Beta; Rheumatic fever
D. Alpha; Strep. Pharyngitis
A. Strep throat (also known as strep. Pharyngitis) can lead to Rheumatic fever if left untreated and displays beta-hemolytic activity.
8. True or False. Under most circumstances, staphylococcus can be found in ~80% of human population where it remains non-symptomatic.
False. Staphylococcus in only found (non-symptomatic) in ~30% of the human population.
9. Define commensal bacteria.
The bacterium neither harms nor benefits from the host from which it obtains nutrients.
10. How can Staphylococcus be differentially tested?
Staphylococcus species are capable of growth in the presence of bile salts.
11. Match the following symptoms with their respective diseases:
1. Folliculitis
D A. Childhood skin disease near mouth/nose
2. Scalded-skin syndrome
E B. Infection of thin, transparent scleral tissue
3. Impetigo
A C. Infection occurs at time of birth
4. Conjunctivitis
B D. Pus-filled lesions on skin or hair
5. Ophthalmia Neonatorum
C E. Ruptured pustules; treated with Penicillin
12. True or False. The causative agent of conjunctivitis can be either bacterial or viral.
True. There are bacterial (staph) and viral forms of conjunctivitis, both resulting in the inflammation of the conjunctiva and ‘pink eye.’
13. True or False. Tuberculosis is best identified by a Gram stain.
False. Mycobacterium show poor Gram staining and show be screened via an acid-fast stain.
14. True or False. You can become infected with TB simply by sharing a drink with someone who is currently infected with TB.
False. As per the Center for Disease Control (CDC) guidelines, simply shaking someone's hand, sharing a drink or even kissing cannot spread TB.
15. Identify the disease based on the following (select all that apply):
It is a small, acid-fast rod usually remaining asymptomatic for up to 20 years. It affects the skin, nerves, upper respiratory tract and eyes of infected individuals.
A. Tuberculosis
B. Leprosy
C. Scalded-skin syndrome
D. Hansen’s disease
E. Bacterial conjunctivitis
B and D. Hansen’s disease is simply another name for Leprosy. Leprosy is characterized by its ability to remain dormant for up to 20 years as well as the effects observed relative to the patient’s skin, nerves, lungs and eyes.
16. Only directly ingesting the pre-formed Clostridium toxin (neither the bacteria nor its spores) will cause disease in adults.
True. The mature (adult) microbiota is capable of killing the bacteria/spores.
17. While visiting his grandparents, a 10-year-old child has green beans for dinner that were harvested from his grandparents’ garden and canned the previous year. Severe illness sets in and the child is taken to the hospital. Botulism is suspected, but what form? Explain your answer.
Foodborne botulism. The child is too old (> 6 months) to be considered for infant botulism and wounds were not present. The green beans were likely improperly canned and under the low-acidic, anaerobic conditions, bacterial growth was encouraged.
18. True or False. Although there is no cure for tetanus, it can be prevented through vaccination.
True. There is no cure for tetanus. However, tetanus is entirely preventable through vaccination.
19. Describe the symptoms and treatment regimen for someone infected with Clostridium perfringens
Clostridium perfringens (also known as Gas gangrene) presents with muscle necrosis, swelling of infected areas, fever and intense gas production. Treatment entails removal of all infected tissue, often resulting in amputation of the affected areas, in conjunction with heavy antibiotic therapies.
20. Why does the alpha toxin (perfringolysin) produced during an infection of gas gangrene cause cell death?
The toxin perforates the membrane. It forms pores in the plasma membrane of host cells resulting in uncontrolled ion fluxes and eventually cell lysis and death.
21. You develop a fever, chills and pneumonia after recently using a warm midst vaporizer in an attempt to open your sinuses. What bacterial disease would a doctor suspect is causing your symptoms? Would the doctor suspect you contracted it from touching (potentially) contaminated doorknobs?
Legionnaires. No—legionella cannot be spread simply by direct contact between people. Legionella can only be transmitted through droplets small enough to be breathed in.
22. True or False. Bubonic plague is often characterized by painfully swollen lymph nodes.
True.
23. Which form of the plague is highly virulent? What does it target?
Pneumonic plague is highly virulent and targets the respiratory (lungs) system.
24. Identify the following disease:
A. Tetanus
B. Anthrax
C. Gas gangrene
D. Frost bite
B. Anthrax—the distinct black center at the site of infection is a hallmark of anthrax infection.
25. Gonnorrhea is caused by:
A. Diplococcic bacteria
B. Staphylococcus bacteria
C. Gram-Negative spirochete
D. RNA virus
A. Diplococcic bacteria.
26. True or False. Chlamydia trachomatis can be grown on an agar plate alone.
False. Chlyamdia is an obligate parasite and requires a host (viable cells) for its growth.
27. Match the following diseases with their respective symptoms if left untreated:
Gonorrhea
C
Syphilis
A
Chlamydia
E
A. Paralysis, blindness and dementia
B. Painfully swollen lymph nodes
C. Cardiac and neurological complications
D. Respiratory failure associated with lock-jaw
E. Infertility and pelvic inflammatory disease.
F. Sore throat, ocular discharge and fever [Show Less]