Practice questions

A carbuncle lesion is the result of an infection with ____________. Etiology?

Boils and carbuncles are caused by a bacterial infection, usually Staphylococcus aureus, which is often found on the skin or in the nose. The bacteria can enter the skin if there's a small injury, bug bite or shaving nick.

What are the morphological features associated with anthrax?

· B. anthracis is a Gram-positive spore-forming bacillus. · It is a very large bacillus measuring 1-1.2 mm in width and 3-5 mm in length. · In smears from infected tissues, the bacteria are found as single, in pairs, and in short chains, the entire chain being surrounded by a capsule. · In culture, B. anthracis grows as long chains and may appear similar to streptobacilli. In these chains, the bacilli are arranged end-to-end and the ends of the bacilli are truncated, not rounded, or often concave and somewhat swollen. This gives the chain of bacilli a "bamboo-stick" appearance

A 35-year-old woman has a red, raised rash on the inside of her thighs. Gram-stained skin scrapings show large budding cells with pseudohyphae. The infection is caused by _____. A) Candida albicans. B) Herpes simplex virus. C) Staphylococcus aureus. D) Streptococcus pyogenes. E) Varicella-zoster virus.

A) Candida albicans.

Which of the following is NOT a characteristic used to identify Streptococcus pyogenes? A) Coagulase-positive B) Group A cell wall antigen C) Group M proteins D) Beta-hemolytic E) Cocci

A) Coagulase-positive

What's the etiological agent of Anthrax?

Anthrax is a serious infectious disease caused by gram-positive, rod-shaped bacteria known as Bacillus anthracis. It occurs naturally in soil and commonly affects domestic and wild animals around the world. People can get sick with anthrax if they come in contact with infected animals or contaminated animal products. Anthrax can cause severe illness in both humans and animals.

What are the virulence factors associated with anthrax?

Bacillus anthracis possesses three primary virulence factors: capsule, lethal toxin, and edema toxin.

The symptoms of meningitis include

Early meningitis symptoms may mimic the flu (influenza). Symptoms may develop over several hours or over a few days. Possible signs and symptoms in anyone older than the age of 2 include: Sudden high fever Stiff neck Severe headache that seems different from normal Headache with nausea or vomiting Confusion or difficulty concentrating Seizures Sleepiness or difficulty waking Sensitivity to light No appetite or thirst Skin rash (sometimes, such as in meningococcal meningitis)

Someone with irregular heart valves would have an increased risk for developing

Heart valve stenosis is also linked to a higher risk for atrial fibrillation. For example, mitral valve stenosis results in an obstruction to blood flow from the left atrium to the left ventricle causing the pressure to increase in the left atrium. As a result, the heart enlarges, and atrial fibrillation can occur.

List two diseases that have vector transmission in chapter 23 that were covered in the PPt notes.

Other viral diseases transmitted by vectors include chikungunya fever, Zika virus fever, yellow fever, West Nile fever, Japanese encephalitis (all transmitted by mosquitoes), tick-borne encephalitis (transmitted by ticks). Many of vector-borne diseases are preventable, through protective measures, and community mobilisation.

Which microbes are known to cause meningitis? How can you distinguish them?

Several types of bacteria can cause meningitis. Leading causes in the United States include: Streptococcus pneumoniae Group B Streptococcus Neisseria meningitidis Haemophilus influenzae Listeria monocytogenes Escherichia coli

What characteristics can be used to identify S. pyogenes?

Streptococcus pyogenes possess a wide variety of virulence factors and can cause severe invasive infections. Streptococcal sore throat (Strep throat) features. The sample for the isolation/identification of S. pyogenes is either pharyngeal exudates, pus, blood, tissue, or body fluids depending on the sites and nature of infection.

A baby arrives at an emergency room suffering from violent muscles spasms and difficulty breathing. The baby's body is so rigid a proper exam is difficult, but the staff note the baby is only a few weeks old and the umbilicus has not healed properly. The signs are consistent with which microbe we studied during this unit?

The signs are consistent with the mirobe Tetanus. Tetanus is a bacterial infection caused by Clostridium tetani, commonly found in the manure, soil, dust and saliva. This disease is characterized by muscle spasms, which begin at the jaw and travels to rest of the body and can also cause muscle fractures. Other symptoms of this infection include headache, fever, abnormally high heart rate, difficulty in breathing, sweating, trouble swallowing and high blood pressure. Therefore, the baby is most likely suffering from tetanus.

What are the three forms of Anthrax? Which is potentially most deadly?

There are three forms of anthrax infection: cutaneous (skin), inhalation (lungs) and gastrointestinal (stomach and intestine). If people have been intentionally exposed, as in a bioterrorist release, contact with skin would be the most likely route of exposure. Inhalation anthrax is considered to be the most deadly form of anthrax. Infection usually develops within a week after exposure, but it can take up to 2 months.

What's the etiological agent of rabbit fever?

Tularemia is a rare infectious disease. Also known as rabbit fever or deer fly fever, it typically attacks the skin, eyes, lymph nodes and lungs. Tularemia is caused by the bacterium Francisella tularensis. The disease mainly affects rabbits, hares, and rodents, such as muskrats and squirrels.