Microbiology: Pseudomonas and Bordetella
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Questions and Answers

What is responsible for the fever and shock associated with sepsis caused by Pseudomonas aeruginosa?

  • Endotoxin (correct)
  • Lipid A
  • Peptidoglycan
  • Exotoxin A

What is the effect of exotoxin A produced by Pseudomonas aeruginosa?

  • Inactivates EF-2 (correct)
  • Activates EF-2
  • Stimulates immune response
  • Causes apoptosis in host cells

Which of the following is a characteristic of Pseudomonas aeruginosa's pathogenesis?

  • Endotoxin leading to fever (correct)
  • Production of necrotizing enzymes
  • Production of a capsular polysaccharide
  • Formation of biofilms exclusively

What role does EF-2 play in the pathogenesis of Pseudomonas aeruginosa?

<p>Inhibits protein synthesis (B)</p> Signup and view all the answers

In the context of Pseudomonas aeruginosa, what does the term 'exotoxin' refer to?

<p>A toxin produced and secreted by living bacteria (D)</p> Signup and view all the answers

What is the primary habitat for Legionella pneumophila?

<p>Environmental water sources (C)</p> Signup and view all the answers

How is Legionella pneumophila transmitted?

<p>Aerosol from the water source (B)</p> Signup and view all the answers

Which of the following is false regarding Legionella pneumophila?

<p>It can be spread through contaminated food. (C)</p> Signup and view all the answers

What role does endotoxin play in Legionella pneumophila?

<p>It is a factor in the pathogenesis of infection. (D)</p> Signup and view all the answers

What type of transmission is not associated with Legionella pneumophila?

<p>Person-to-person transmission (A)</p> Signup and view all the answers

What disease is associated with Bordetella pertussis?

<p>Whooping cough (D)</p> Signup and view all the answers

Which of the following best describes the morphology of Bordetella pertussis?

<p>Small gram-negative rods (A)</p> Signup and view all the answers

In which part of the human body does Bordetella pertussis primarily reside?

<p>Respiratory tract (C)</p> Signup and view all the answers

How is Bordetella pertussis transmitted from one person to another?

<p>Via respiratory droplets (C)</p> Signup and view all the answers

Which characteristic does NOT apply to Bordetella pertussis?

<p>Large spherical shape (B)</p> Signup and view all the answers

What component of Bordetella pertussis damages the ciliated epithelium?

<p>Tracheal cytotoxin (D)</p> Signup and view all the answers

Which part of the respiratory tract is primarily affected by Bordetella pertussis?

<p>Trachea (A)</p> Signup and view all the answers

What is the primary effect of the tracheal cytotoxin in Bordetella pertussis infection?

<p>Damages ciliated epithelium (B)</p> Signup and view all the answers

Which type of pathogen is Bordetella pertussis?

<p>Bacterium (D)</p> Signup and view all the answers

How does Bordetella pertussis primarily affect respiratory function?

<p>Damages respiratory epithelium (D)</p> Signup and view all the answers

What is a predisposing factor for certain health conditions?

<p>Smoking (C)</p> Signup and view all the answers

How does smoking affect health according to the predisposition factors?

<p>Damages alveolar macrophages (C)</p> Signup and view all the answers

Which age group is considered a predisposing factor?

<p>Older than 55 years (C)</p> Signup and view all the answers

What is the impact of high alcohol intake as a predisposing factor?

<p>Increases risk of health issues (A)</p> Signup and view all the answers

Which combination of factors is likely to predispose individuals to health issues?

<p>High alcohol intake and smoking (D)</p> Signup and view all the answers

What type of stain was used for the lung sections in the study?

<p>H &amp; E stain (B)</p> Signup and view all the answers

Which organism was isolated from the patient in the study?

<p>Legionella pneumophila (C)</p> Signup and view all the answers

What was the modification used to stain the lung sections effectively?

<p>CDC's modification of Dieterle silver impregnation procedure (A)</p> Signup and view all the answers

In what type of specimen were Legionella pneumophila isolated from?

<p>Lung sections (D)</p> Signup and view all the answers

What can the isolation of Legionella pneumophila suggest about the patient's condition?

<p>The patient is experiencing a bacterial respiratory infection (C)</p> Signup and view all the answers

Flashcards

Pseudomonas aeruginosa

A type of bacteria that can cause infections in humans, particularly in individuals with weakened immune systems.

Endotoxin

A toxin released by bacteria that can cause fever and shock, often associated with sepsis.

Exotoxin A

A protein produced by Pseudomonas aeruginosa that can inactivate a key protein involved in protein synthesis.

EF-2

A protein involved in translation, the process of making proteins.

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Sepsis

A serious condition caused by the body's immune system overreacting in response to an infection.

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Whooping cough

A bacterial disease that causes the characteristic coughing fits known as 'whooping cough'. It is highly contagious and primarily affects children.

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Bordetella pertussis

A type of bacteria responsible for causing whooping cough. It's small and has a rod-like shape.

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Habitat of Bordetella pertussis

The primary location where Bordetella pertussis bacteria live and multiply in the body.

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Transmission of Bordetella pertussis

The primary method by which Bordetella pertussis bacteria spread from person to person.

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Gram-negative rods

A classification for bacteria based on their appearance under a microscope. They appear as small rods under staining.

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Legionella pneumophila habitat

Environmental water sources, such as lakes, rivers, or even showerheads.

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Legionella transmission

Spreading through tiny droplets of water in the air, like mist or spray.

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Legionella pneumophila

A type of bacteria that can cause Legionnaires' disease.

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Pathogenesis

The process by which a disease develops and progresses within the body.

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Tracheal Cytotoxin

A toxin produced by Bordetella pertussis that specifically damages the ciliated epithelial cells in the respiratory tract.

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Ciliated epithelium

Tiny, hair-like projections that line the respiratory tract and help move mucus and foreign substances out of the body.

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Whooping Cough (Pertussis)

The condition characterized by a severe, hacking cough followed by a whooping sound, usually caused by Bordetella pertussis infection.

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Age as a Predisposing Factor

Individuals aged 55 and above are at an increased risk for developing certain health conditions, including lung infections.

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Smoking's Impact on Alveolar Macrophages

Smoking damages alveolar macrophages, specialized cells in the lungs that engulf and destroy harmful substances.

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Alcohol and Immune System

Excessive alcohol consumption can weaken the immune system, making individuals more susceptible to infections.

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What are Predisposing Factors?

Predisposing factors are conditions or characteristics that increase the likelihood of developing a particular disease or condition.

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Predisposing Factors Examples

Factors that increase risk of developing a disease can include age, lifestyle habits (like smoking or alcohol consumption), and underlying health conditions.

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Dieterle silver impregnation

A staining technique that uses silver ions to highlight the bacteria Legionella pneumophila.

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CDC's modification of Dieterle silver impregnation

A procedure used to identify Legionella pneumophila in samples, often used in clinical settings.

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H & E stained lung sections

A histological section of lung tissue, prepared for microscopic examination.

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H & E stained lung sections of patient from whom legionella pneumophila was isolated

A specimen of lung tissue taken from a patient infected with Legionella pneumophila.

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Study Notes

Gram-Negative Rods

  • Pseudomonas aeruginosa

    • Diseases: wound infection, UTI, pneumonia, sepsis, nosocomial infections (especially in burn patients), endocarditis in intravenous drug users.
    • Characteristics: aerobic gram-negative rods, non-lactose-fermenting, pyocyanin (blue-green) pigment, oxidase-positive.
    • Habitat & Transmission: environmental water sources, inhabits skin, upper respiratory tract & colon, transmission via water aerosols, aspiration & fecal contamination.
    • Pathogenesis: endotoxin responsible for fever and shock with sepsis; exotoxin A inactivates EF-2; pili and capsule mediate attachment and inhibit phagocytosis; glycocalyx-producing strains predominate in chronic infections in cystic fibrosis patients; severe burns & neutropenia are predisposing factors
    • Prevention: disinfection of water-related equipment in hospitals, handwashing, prompt removal of urinary and intravenous catheters; no vaccine.
  • Haemophilus influenzae

    • Diseases: sinusitis, otitis media, pneumonia are common; epiglottitis is uncommon; meningitis was a leading cause but vaccination greatly reduced cases.
    • Characteristics: small gram-negative (coccobacillary) rods, requires factors X (hemin) and V (NAD) for growth; of six capsular polysaccharide types, type b causes 95% of invasive disease; type b capsule is polyribitol phosphate.
    • Habitat & Transmission: upper respiratory tract, transmission via respiratory droplets.
    • Pathogenesis: polysaccharide capsule is the most important determinant of virulence; unencapsulated ("untypeable") strains cause mucosal infections but not invasive infections; IgA protease is produced; most cases of meningitis occur in children younger than 2 years due to waning maternal antibody & inadequate immune response to capsular polysaccharides.
    • Treatment: Ceftriaxone is the treatment of choice for meningitis; approximately 25% of strains produce β-lactamase.
    • Prevention: vaccine containing type b capsular polysaccharide conjugated to diphtheria toxoid or other protein, given between 2 & 18 months of age; rifampin can prevent meningitis in close contacts.
  • Bordetella pertussis

    • Diseases: whooping cough (pertussis).
    • Characteristics: small gram-negative rods.
    • Habitat & Transmission: human respiratory tract, transmission via respiratory droplets.
    • Pathogenesis: pertussis toxin stimulates adenylate cyclase by adding ADP-ribose onto inhibitory G protein; toxin has two components (subunit A has ADP-ribosylating activity, subunit B binds toxin to cell surface receptors); pertussis toxin causes lymphocytosis in blood, preventing lymphocytes from entering tissue, leading to retention in blood; tracheal cytotoxin damages ciliated epithelium of respiratory tract.
    • Clinical presentation: whooping cough is acute tracheobronchitis, starting with mild upper respiratory symptoms, followed by severe paroxysmal cough lasting 1-4 weeks; paroxysmal cough involves hacking coughs with copious mucus, ending with an inspiratory whoop; in adults, paroxysmal cough of varying severity, lasting weeks, with characteristic whoop often absent.
    • Treatment: erythromycin.
    • Prevention: acellular vaccine containing pertussis toxoid (recommended); killed vaccine contains whole organisms, given to children in combination with diphtheria & tetanus toxoids (DTaP).
  • Legionella pneumophila

    • Diseases: Legionnaires' disease ("atypical" pneumonia; mild influenzalike illness to severe pneumonia, accompanied by mental confusion, nonbloody diarrhea and microscopic hematuria, cough with scanty and nonpurulent sputum; most cases resolve spontaneously in 7 to 10 days; infection can be fatal in older or immunocompromised patients; Pontiac fever is mild, flu-like form that does not result in pneumonia.
    • Characteristics: gram-negative rods (stain poorly with standard Gram stain), require iron & cysteine for growth in culture.
    • Habitat & Transmission: environmental water sources, transmission via aerosol from water source; person-to-person transmission is not present
    • Pathogenesis: has endotoxin; predisposing factors include age over 55, smoking (damages alveolar macrophages), high alcohol intake, and immunosuppression (renal transplant recipients); replicates intracellularly, so cell-mediated immunity is important host defense

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Test your knowledge on the pathogenesis, characteristics, and transmission of Pseudomonas aeruginosa and Bordetella pertussis. This quiz covers exotoxins, habitats, and disease associations linked to these bacteria. Ideal for microbiology students wanting to enhance their understanding of these pathogens.

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