Pseudomonas Aeruginosa
Staphylococcus aureus and Pseudomonas aeruginosa are the most likely organisms to be found with a history of injection drug use.
What our notes say
- Staphylococcus aureus and Pseudomonas aeruginosa are the most likely organisms to be found with a history of injection drug use. (CARDIOVASCULAR PATHOLOGY — Past Paper Questions & Answers)
- Associated with formation of a bacterial biofilm: classic example is airway colonization in a cystic fibrosis patient with a mucoid (alginate-producing) strain of *Pseudomonas aeruginosa* (this exact scenario is used to test biofilm concept generally, not just Staph) (Streptococcus Classification, S. pyogenes, Rheumatic Fever, AGN)
- *Green-tinged, fruity/grape-like odoured sputum is a classic clinical clue for Pseudomonas aeruginosa, a leading cause of ventilator-associated pneumonia.* (End Sem Cat: Respiratory Pathology: Emphysema, ARDS, Pneumoconiosis)
- Sputum: culture for *Haemophilus influenzae*, *Pseudomonas aeruginosa*, *Staph aureus*; AFB/GeneXpert for TB and non-tuberculous mycobacteria; fungal culture. (Bronchiectasis)
- Airway colonization in a cystic fibrosis patient with a mucoid (alginate-producing) strain of Pseudomonas aeruginosa (Bacteriology and Entomology Supplementary Exam)
- He has had a series of upper respiratory tract infections, with organisms including Staphylococcus aureus, Streptococcus pneumoniae, and Pseudomonas aeruginosa cultured. (Immunopathology complete mcqs — Past Paper Questions & Answers)
Study material on Pseudomonas Aeruginosa
- End Sem Cat: Respiratory Pathology: Emphysema, ARDS, Pneumoconiosis
- CARDIOVASCULAR PATHOLOGY
- Streptococcus Classification, S. pyogenes, Rheumatic Fever, AGN
Practice questions on Pseudomonas Aeruginosa
Which of the following β-lactam antibiotics is active against Pseudomonas aeruginosa?
- Amoxicillin
- Piperacillin
- Cephalexin
- Penicillin V
- Pseudomonas requires specific β-lactams with structural features allowing penetration through its outer membrane porins.
Answer: B. Piperacillin is an extended-spectrum penicillin with anti-pseudomonal activity. It's often combined with tazobactam (a β-lactamase inhibitor) for broader coverage. Pseudomonas requires specific β-lactams with structural features allowing penetration through its outer membrane porins. --- ---
Which of the following β-lactam antibiotics is active against Pseudomonas aeruginosa?
- Amoxicillin
- Piperacillin
- Cephalexin
- Penicillin V
- Pseudomonas requires specific β-lactams with structural features allowing penetration through its outer membrane porins.
Answer: B. Piperacillin is an extended-spectrum penicillin with anti-pseudomonal activity. It's often combined with tazobactam (a β-lactamase inhibitor) for broader coverage. Pseudomonas requires specific β-lactams with structural features allowing penetration through its outer membrane porins. --- ---
Green-blue pus with a fruity odor in a burn patient is characteristic of an infection with Pseudomonas aeruginosa. The green color is due to pyocyanin and the fruity odor is due to pyrazinamide production.
- A) Pseudomonas aeruginosa
- B) Staphylococcus aureus
- C) Streptococcus pyogenes
- D) Proteus mirabilis
Answer: A. Pseudomonas aeruginosa is an opportunistic pathogen often associated with hospital-acquired infections, particularly in burn patients. It is known for producing characteristic pigments like pyocyanin (blue-green) and elastase, which contribute to the color and odor of the wound exudate.
A 72-year-old man is admitted to the hospital from a nursing home with severe pneumonia. He was discharged from the hospital 1 week ago after open heart surgery. The patient has no known allergies. Which of the following regimens is most appropriate for empiric coverage of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa in this patient?
- Vancomycin plus Piperacillin-tazobactam
- Ceftriaxone plus Azithromycin
- Levofloxacin monotherapy
- Linezolid plus Cefepime
Answer: A. This patient is at high risk for healthcare-associated pneumonia (HAP) with resistant pathogens. Vancomycin provides MRSA coverage, and piperacillin-tazobactam provides broad-spectrum Gram-negative coverage, including Pseudomonas. Levofloxacin alone may not adequately cover MRSA, and ceftriaxone/azithromycin is insufficient for MRSA and Pseudomonas.
A 72-year-old man is admitted to the hospital from a nursing home with severe pneumonia. He was discharged from the hospital 1 week ago after open heart surgery. The patient has no known allergies. Which of the following regimens is most appropriate for empiric coverage of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa in this patient with hospital-acquired pneumonia
- Amoxicillin-clavulanate + Doxycycline
- Ceftriaxone + Azithromycin
- Piperacillin-tazobactam + Vancomycin
- Levofloxacin monotherapy
Answer: C. This patient has risk factors for hospital-acquired pneumonia, including recent hospitalization and nursing home residence. Empiric coverage for MRSA (Vancomycin) and Pseudomonas aeruginosa (Piperacillin-tazobactam is an antipseudomonal beta-lactam) is appropriate for severe cases.
Which of the following statements regarding Pseudomonas aeruginosa is correct?
- It is an obligate intracellular pathogen.
- It is a common cause of opportunistic infections in immunocompromised individuals.
- It is most commonly acquired through ingestion of contaminated food.
- It is characterized by its inability to grow in the presence of oxygen.
Answer: B. Pseudomonas aeruginosa is an opportunistic, Gram-negative rod that is ubiquitous in the environment. It frequently causes infections in patients with weakened immune systems, such as those with cystic fibrosis, burns, or prolonged hospitalization, often in healthcare settings.