A patient with pneumonia has negative H2S and positive urease on culture, what is the likely organism?

A patient with pneumonia has negative H2S and positive urease on culture, what is the likely organism?

• A. Klebsiella pneumoniae
• B. Escherichia coli
• C. Proteus mirabilis
• D. Enterobacter cloacae

Answer: (A)

The organism most likely responsible for the patient’s pneumonia, given the laboratory results of negative H2S and positive urease, is Klebsiella pneumoniae. This organism is known for causing pneumonia, particularly in individuals with underlying health issues or those who are immunocompromised. Klebsiella pneumoniae typically tests negative for hydrogen sulfide (H2S) production, which helps differentiate it from certain other bacteria that can produce H2S, such as Proteus mirabilis. Additionally, Klebsiella is positive for urease, meaning it can hydrolyze urea to produce ammonia and increase the pH of its environment. This urease activity is a distinguishing feature that supports its identification. In clinical microbiology, these biochemical tests are crucial for narrowing down the possible causative agents of infections, particularly those affecting the respiratory tract. The positive urease result reinforces the identification of Klebsiella over other potential options that may have different urease activity patterns or H2S production.

The organism most likely responsible for the patient’s pneumonia, given the laboratory results of negative H2S and positive urease, is Klebsiella pneumoniae. This organism is known for causing pneumonia, particularly in individuals with underlying health issues or those who are immunocompromised.

Klebsiella pneumoniae typically tests negative for hydrogen sulfide (H2S) production, which helps differentiate it from certain other bacteria that can produce H2S, such as Proteus mirabilis. Additionally, Klebsiella is positive for urease, meaning it can hydrolyze urea to produce ammonia and increase the pH of its environment. This urease activity is a distinguishing feature that supports its identification.

In clinical microbiology, these biochemical tests are crucial for narrowing down the possible causative agents of infections, particularly those affecting the respiratory tract. The positive urease result reinforces the identification of Klebsiella over other potential options that may have different urease activity patterns or H2S production.