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

    What is the primary habitat for Legionella pneumophila?

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

    How is Legionella pneumophila transmitted?

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

    Which of the following is false regarding Legionella pneumophila?

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

    What type of transmission is not associated with Legionella pneumophila?

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

    What disease is associated with Bordetella pertussis?

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

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

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

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

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

    How is Bordetella pertussis transmitted from one person to another?

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

    Which characteristic does NOT apply to Bordetella pertussis?

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

    What component of Bordetella pertussis damages the ciliated epithelium?

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

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

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

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

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

    Which type of pathogen is Bordetella pertussis?

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

    How does Bordetella pertussis primarily affect respiratory function?

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

    What is a predisposing factor for certain health conditions?

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

    How does smoking affect health according to the predisposition factors?

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

    Which age group is considered a predisposing factor?

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

    Which organism was isolated from the patient in the study?

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

    In what type of specimen were Legionella pneumophila isolated from?

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

    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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    8L-Pseudomonas-Haemophilus-Bordetella -Legionella pneumophila PDF

    Description

    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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