Microbiology Chapter 18 Flashcards
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Questions and Answers

What enzyme digests connective tissue of the host? (also known as the 'spreading factor')

hyaluronidase

What systemic infection, caused by S.aureus, results in abscess formation in the bone?

osteomyelitis

What toxin (a virulence factor of S.aureus) damages the cell membrane of neutrophils and macrophages, causing them to lyse?

leukocidin

A patient has symptoms of fever, vomiting, rash, and organ failure. The patient recently used tampons for the first time. What could be the cause of this disease?

<p>toxic shock syndrome</p> Signup and view all the answers

S.aureus is grown typically on what type of agar?

<p>blood agar</p> Signup and view all the answers

What test is used to differentiate S.aureus from other strains of Staphylococcus?

<p>coagulase test</p> Signup and view all the answers

What toxin (common virulence factor of S.aureus) induces nausea, vomiting, and diarrhea, and acts upon the gastrointestinal tract of humans?

<p>enterotoxins</p> Signup and view all the answers

Which strain of Staphylococci are commonly found in the anterior nares and in the skin, nasopharynx, and intestine? (Hint: This bacteria can cause furuncles, carbuncles, and impetigo)

<p>S.aureus</p> Signup and view all the answers

What disease would you consider the cause of an infant's red, peeling skin (desquamation)?

<p>Staphylococcal Scalded Skin Syndrome (SSSS)</p> Signup and view all the answers

What strain of Staphylococcus epidermidis populates the scalp, face, and external ear?

<p>Staphylococcus capitis</p> Signup and view all the answers

An erythrogenic toxin is responsible for the bright red rash typical of this disease.

<p>scarlet fever</p> Signup and view all the answers

This is a member of the alpha-hemolytic streptococci group, producing a green coloration on blood agar plates. They can be found in the oral cavity, nasopharynx, genital tract, and skin. These species can cause serious systemic infections, although most of them are opportunists.

<p>viridians streptococci</p> Signup and view all the answers

This is the most serious infection from viridians streptococci group. In this condition, blood-borne bacteria settle on areas of the heart lining or valves that have previously been injured by rheumatic fever or valve surgery.

<p>subacute endocarditis</p> Signup and view all the answers

This bacteria is in the beta-hemolytic group B streptococci and is the most prevalent cause of neonatal pneumonia, sepsis, and meningitis in the United States and Europe.

<p>S.agalactiae</p> Signup and view all the answers

This beta-hemolytic streptococcus not only causes scarlet fever. It also causes the skin infections impetigo and erysipelas.

<p>S.pyogenes</p> Signup and view all the answers

The name of the disease that follows overt or subclinical pharyngitis in children. This disease can cause carditis with extensive valve damage, arthritis, and chorea.

<p>rheumatic fever</p> Signup and view all the answers

This is a member of the Viridans group that produces slime layers that adhere to teeth. They are the basis for plaque and are involved in dental caries.

<p>S.mutans</p> Signup and view all the answers

It is an extracellular enzyme from beta-hemolytic S.pyogenes that is similar to staphylokinase that activates a pathway leading to the digestion of fibrin clots and may play a role in invasion.

<p>streptokinase</p> Signup and view all the answers

This bacterium is involved in 60% to 70% of bacterial pneumonias and is also a major cause of meningitis and otitis media in young children.

<p>S.pneumonia</p> Signup and view all the answers

The antibiotic test used to distinguish streptococcus pyogenes from other members of streptococci?

<p>Bacitracin</p> Signup and view all the answers

What cell is gram negative, no flagella or spores, has capsules, bean-shaped and paired with flat sides touching; and has an outer membrane with lipopolysaccharides in the cell wall?

<p>Neisseriae</p> Signup and view all the answers

What is the name of the sexually transmitted disease that is named after the Greek physician Claudius Galen, who thought it was caused by an excess flow of semen?

<p>Gonorrhea</p> Signup and view all the answers

A contributing factor in the pathogenicity of Gonococcal is a protease that cleaves what mucosal surfaces and stops their protective effects?

<p>secretory antigen IgA</p> Signup and view all the answers

What is one disease found in females when an infection ascends from the vagina and cervix to higher reproductive structures such as the uterus and fallopian tubes? Also, it is characterized by fever, abdominal pain, and tenderness.

<p>Pelvic Inflammatory Disease (PID)</p> Signup and view all the answers

What is a serious human pathogen that is usually associated with cerebrospinal meningitis? It has a polysaccharide capsule, adhesive fimbriae, and IgA protease.

<p>Neisseria meningitidis</p> Signup and view all the answers

One of the virulence factors of N.meningitides with pathologic effects is the lipopolysaccharide released from the cell wall when the microbe lyses?

<p>endotoxin</p> Signup and view all the answers

One clinical sign of meningococcemia are small, non-raised spots called what, and are due to subcutaneous hemorrhages?

<p>petechiae</p> Signup and view all the answers

What vaccine is used for meningococcal infection and is a meningococcal conjugate vaccine recommended for persons between 2 and 55 years of age?

<p>MCV4 (Menactra)</p> Signup and view all the answers

What test is used to differentiate true pathogens from normal Neisseria species that live in the human body and can be present in infections in the fluid? The specimens are taken after collection and streaked on this medium and incubated in a high CO2 atmosphere.

<p>Thayer-Martin (MTM) medium</p> Signup and view all the answers

What species is found in the normal human nasopharynx and is associated with several clinical syndromes such as meningitis, endocarditis, otitis media, bronchopulmonary infections, and neonatal conjunctivitis?

<p>Branhamella (Moraxella) catarrhalis</p> Signup and view all the answers

Study Notes

Enzymes and Toxins

  • Hyaluronidase: Enzyme that digests host connective tissue, also called "spreading factor."
  • Leukocidin: Toxin from S.aureus that damages and lyses neutrophils and macrophages.
  • Enterotoxins: Toxin from S.aureus that induces gastrointestinal symptoms like nausea and diarrhea.

Infections and Diseases

  • Osteomyelitis: Systemic infection caused by S.aureus leading to abscess formation in bones.
  • Toxic Shock Syndrome: Disease characterized by fever, vomiting, rash, and organ failure, often associated with tampon use.
  • Staphylococcal Scalded Skin Syndrome (SSSS): Disease causing red, peeling skin in infants.
  • Subacute Endocarditis: Serious infection from viridians streptococci affecting the heart lining or valves.
  • Rheumatic Fever: Follows pharyngitis and can cause valvular heart damage, arthritis, and chorea.

Bacterial Identification

  • S.aureus Growth Medium: Typically grown on blood agar.
  • Coagulase Test: Used to differentiate S.aureus from other Staphylococcus strains.
  • Bacitracin Test: Distinguishes S.pyogenes from other streptococci species.
  • Thayer-Martin Medium (MTM): Test medium for differentiating true pathogens from normal Neisseria species.

Streptococci Types

  • Viridians Streptococci: Alpha-hemolytic group causing opportunistic infections; produces a green coloration on blood agar.
  • S.agalactiae: Beta-hemolytic streptococcus and leading cause of neonatal pneumonia, sepsis, and meningitis.
  • S.pyogenes: Causes scarlet fever and skin infections, including impetigo and erysipelas.

Neisseria General Information

  • Neisseriae: Gram-negative, bean-shaped bacteria with a polysaccharide capsule.
  • Neisseria Meningitidis: Associated with cerebrospinal meningitis, possesses virulence factors such as IgA protease and endotoxin.
  • Gonorrhea: Sexually transmitted disease linked to ancient medical theories about semen flow.
  • Endotoxin: Released from N.meningitidis upon lysis, contributing to pathogenicity.
  • Petechiae: Clinical signs of meningococcemia, presenting as small, nonraised spots due to hemorrhages.

Clinical Syndromes

  • Branhamella (Moraxella) catarrhalis: Present in the nasopharynx, linked to various infections such as meningitis and otitis media.
  • Pelvic Inflammatory Disease (PID): Infection in females during ascent from vagina to reproductive structures, characterized by fever and abdominal symptoms.

Vaccination

  • MCV4 (Menactra): Conjugate vaccine for meningococcal infection, recommended for ages 2 to 55.

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Test your knowledge of key concepts from Microbiology Chapter 18 with these flashcards. This quiz covers important terms and definitions, including enzymes, infections, and toxins. Perfect for students looking to reinforce their understanding of microbiological principles.

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