Portage Microbiology Module 5 Exam

The concept of treating all samples, whether known or unknown, as potentially hazardous (or pathogenic) materials is known as __________

universal precautions

List at least 3 observations a researcher would be sure to note while assessing an unknown microbial sample.

1. any motility

2. size/shape

3. gram status (gram-positive or gram-negative)

4. presence of any chemical reactions

5. changes in color

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 would need to determine the motility before gram status. You can observe motility on a wet mount and then heat fix your sample to gram stain your sample. If you were to

begin with using gram staining, you would kill your sample with heat fixing, you would not be able to observe any motility.

A facultative anaerobe is a microorganism capable of growth under what conditions?

aerobic and anaerobic conditions

As Streptococcus is catalase negative would it thrive or die in the presence of peroxides? Why?

It would thrive because it does not bubble when it comes in contact. Streptococcus is gram negative, anaerobic.

Catalase negative = no bubble formation

Catalase positive = bubble formation

Streptococcus is most often streaked onto:

Blood agar

True or False. The Lancefield groups are used to subdivide antigenic groups of gamma-hemolytic Streptococcus

False

The distinctions for Lancefield subgroupings lie in its: (select all that apply)

Carbohydrate composition of antigens

Left untreated, strep throat can progress to ______ , which displays _____ hemolytic activity.

Rheumatic fever; beta

True or False. Under most circumstances, staphylococcus can be found in ~80% of human population where it remains non-symptomatic.

False

Define commensal bacteria.

The bacterium neither harms nor benefits from the host from which it obtains nutrients.

Match the step of infection to its description.

Invasion: Pathogen passes through or between cells to access deeper tissues and nutrients

Evasion: Pathogen suppresses host's immune system so it can continue replicating

Transmission: Pathogen is passed to another host to restart lifecycle.

Match the following diseases with their respective symptoms:

D - Pus-filled lesions on skin or hai

E - Ruptured pustules; treated with penicillin

A - Childhood skin disease near mouth/nose

B - Infection of thin, transparent scleral tissue

C - Infection occurs at time of birth

True or False. The causative agent of conjunctivitis can be either bacterial or viral.

True

True or False. An acid-fast stain is best suited to identify tuberculosis (as opposed to a gram-stain).

True

True or False. Although TB must be inhaled and reside in the lung in order to cause infection, TB can also spread to the brain, spine, and kidneys.

True

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.

Leprosy

Hansen's Disease

True or False. Directly ingesting clostridium or its associated spores will not cause illness in adults.

True

A 5-month-old child is given honey at breakfast and begins showing symptoms consistent with botulism. Would the child's illness be classified as foodborne, infant, or wound botulism? Explain why you chose this answer.

Infant botulism. The honey was improperly canned/jarred and is a low acid food under anaerobic conditions. Honey is a potential carrier of clostridium. The GI tract of infants is not developed enough to ingest honey.

True or False. Although there is no cure for tetanus, it can be prevented through vaccination.

True

Identify the medical condition characterized by robust carbohydrate fermentation under anaerobic conditions, swelling of the infected areas and fever.

Gas gangrene. It presents with muscle necrosis, swelling of the infected areas, and fever. Treatment

options include removal of the infected areas and amputation

Why does the alpha toxin (perfringolysin) produced during an infection of gas gangrene cause cell death?

It causes cell death because the toxin perforates the membrane. It forms pores in the plasma membrane of the host cells.

You develop a fever, chills, and pneumonia after recently returning from a getaway weekend where you sat in a hot tub. What bacterial disease would a doctor suspect is causing your symptoms? Would the doctor suspect you contracted it from another person?

Legionarres. You cannot contract Legionarres from direct contract with another person. It is transmitted through droplets small enough to be inhaled.

True or False. Bubonic plague is often characterized by painfully swollen lymph nodes.

True

Which form of the plague is the most rare? What does it target?

The most rare type of plague is septicmetic, which targets the blood system.

Identify the following disease:

Lyme disease. The trademark 'bulls-eye' rash is a clear indicator.

Syphilis is caused by:

Gram-Negative spirochete

True or False. Chlyamida is an obligate parasite and as such can be grown on agar plates alone.

False

Match the following diseases with their respective symptoms if left untreated:

1. Gonorrhea

2. Syphilis

3. Chlamydia

1. C. - Cardiac and neurological complications

2. A. - Paralysis, blindness, dementia

3. E. - Infertility and pelvic inflammatory disease