Microbiology Chapter 19 Flashcards

Questions and Answers

Which of the following bacteria is a genus of high G+C Gram-positive bacteria?

Mycobacterium (correct)

Staphylococcus

Escherichia

Clostridium

Which of the following has been historically classified as Gram-negative bacteria but is genetically more similar to low G+C Gram-positive bacteria?

Escherichia

Mycoplasmas (correct)

Salmonella

Shigella

What is one feature that differentiates Staphylococcus aureus from other species of staphylococci?

It can produce coagulase.

Over 90% of Staphylococcus aureus bacteria can withstand the effect of penicillin. Why?

They produce beta-lactamase Signup and view all the answers

A woman comes to the ER with fever and vomiting. She soon develops a red rash all over her body, and her blood pressure begins to drop. What is one possible diagnosis?

Toxic shock syndrome Signup and view all the answers

What type of bacteria are most likely found in a severe inflammation wound showing Gram-positive cocci in irregular clusters, kinase and coagulase positive, and able to grow in the presence of most antibiotics except vancomycin?

MRSA Signup and view all the answers

Streptococci are frequently classified by?

The bacteria's Lancefield antigen Signup and view all the answers

How do group A streptococci camouflage themselves from white blood cells?

They have hyaluronic acid capsules. Signup and view all the answers

Which of the following diseases is considered an autoimmune disease triggered by bacterial infection?

Rheumatic fever Signup and view all the answers

Which of the following statements about 'flesh-eating' streptococci is FALSE?

It is considered a common complication of pyoderma Signup and view all the answers

Streptococcus agalactiae is associated with which of the following diseases?

Neonatal bacteremia, neonatal meningitis, and neonatal pneumonia. Signup and view all the answers

Which of the following statements regarding Streptococcus pyogenes is FALSE?

It produces protein A, which inhibits opsonization Signup and view all the answers

What differentiates virulent strains of Streptococcus pneumoniae from nonvirulent strains?

The presence of a polysaccharide capsule that protects it from digestion after endocytosis. Signup and view all the answers

Untreated streptococcal pharyngitis may progress to?

Scarlet fever or rheumatic fever Signup and view all the answers

The Quellung reaction is used to diagnose?

Streptococcus pneumoniae. Signup and view all the answers

Otitis media may lead to dangerous meningitis in children due to infection with?

Streptococcus pneumoniae. Signup and view all the answers

Which of the following staphylococcal virulence factors produce the signs and symptoms of scalded skin syndrome?

Exfoliative toxin. Signup and view all the answers

During a stay in the hospital, an accident victim develops symptoms of bacteremia. A blood sample shows the presence of Gram-positive cocci in pairs. Lab tests determine that the bacteria are nonhemolytic and bile salt tolerant. The bacteremia is likely due to?

Enterococcus. Signup and view all the answers

Which of the following streptococci is associated with dental caries?

Viridans streptococci. Signup and view all the answers

Anthrax, which means 'charcoal', derives its name from?

The black eschars it produces on human skin. Signup and view all the answers

Which of the following statements about Bacillus anthracis is FALSE?

It is primarily a disease of humans. Signup and view all the answers

Which of the following bacteria produce one of the most deadly bacterial toxins known?

Clostridium botulinum. Signup and view all the answers

Which of the following bacteria can cause life-threatening pseudomembranous colitis?

Clostridium difficile. Signup and view all the answers

How does the toxin from Clostridium tetani produce its action?

The smaller polypeptide of its toxin can block the release of inhibitory neurotransmitters by inhibitory neurons in the central nervous system, causing simultaneous contraction of both muscles in an antagonistic pair. Signup and view all the answers

Which of the following statements concerning tetanus is FALSE?

Its only source is from deep puncture wounds from rusty nails. Signup and view all the answers

Listeria's virulence is directly related to its ability to?

Live within cells and thus avoid exposure to the immune system of its host. Signup and view all the answers

Which of the following bacteria divide by 'snapping division' in which daughter cells remain attached in characteristic V-shapes?

Corynebacterium. Signup and view all the answers

Study Notes

Bacteria Characteristics and Classification

Mycobacterium is a genus of high G+C Gram-positive bacteria.
Mycoplasmas have been historically classified as Gram-negative but are genetically similar to low G+C Gram-positive bacteria.
Staphylococcus aureus is differentiated from other staphylococci by its ability to produce coagulase.
MRSA (Methicillin-resistant Staphylococcus aureus) displays Gram-positive cocci in irregular clusters, positive for kinase and coagulase, resistant to most antibiotics except vancomycin.

Staphylococcus and Streptococcus Infections

Over 90% of Staphylococcus aureus can resist penicillin due to beta-lactamase production.
Symptoms like fever, vomiting, and a sudden drop in blood pressure can indicate toxic shock syndrome.
Streptococci are classified based on the Lancefield antigen; group A streptococci use hyaluronic acid capsules to evade white blood cell detection.
Rheumatic fever is an autoimmune disease triggered by bacterial infection.

Diseases and Complications

Streptococcus agalactiae is associated with neonatal illnesses, including bacteremia, meningitis, and pneumonia.
Streptococcus pyogenes does not produce protein A, which would inhibit opsonization; its virulent strains have a protective polysaccharide capsule.
Untreated streptococcal pharyngitis can lead to scarlet fever or rheumatic fever.
The Quellung reaction is a diagnostic test for Streptococcus pneumoniae.

Miscellaneous Bacteria and Their Effects

Otitis media due to Streptococcus pneumoniae can lead to severe meningitis.
Exfoliative toxin from Staphylococcus causes the symptoms of scalded skin syndrome.
Enterococcus is indicated in cases of bacteremia characterized by Gram-positive cocci in pairs, nonhemolytic, and bile salt tolerant.
Viridans streptococci are associated with dental caries.

Toxins and Other Pathogens

Anthrax, translated as "charcoal," is named for the black eschars it produces on the skin.
Clostridium botulinum produces one of the most potent bacterial toxins.
Clostridium difficile is linked to life-threatening pseudomembranous colitis.
Clostridium tetani's toxin blocks inhibitory neurotransmitter release, causing unopposed muscle contractions.
Tetanus can be contracted from sources beyond just rusty nails, contradicting the idea of puncture wounds as the sole cause.

Additional Microbial Characteristics

Listeria can evade the immune system by living within host cells, enhancing its virulence.
Corynebacterium divides through "snapping division," resulting in daughter cells maintaining a V-shape formation.

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Description

Test your knowledge with these flashcards from Microbiology Chapter 19. Focus on the characteristics and classifications of different bacterial genera. This quiz covers key concepts such as Gram-positive and Gram-negative bacteria as well as specific traits of Staphylococcus aureus.