Question

A patient presented with 70% burns. A test was done on a sample collected from the burnt site as shown in the picture in suspicion of the probable causative organism which is an obligate aerobe. What's the microbe?

• A. Pseudomonas aeruginosa
• B. Meningococcus
• C. Streptococcus pyogenes
• D. Pneumococcus

Hint:

Think of the obligate aerobe that commonly colonizes burn wounds and produces a characteristic blue-green pigment.

Answer 1

The Correct Option is A

Step 1: Identify the clinical context. The patient has 70% burns -- a major risk factor for secondary bacterial infection. The question specifies the causative organism is an obligate aerobe.

Step 2: Recall organisms associated with burn wound infections. Burn wounds are particularly susceptible to Pseudomonas aeruginosa, which thrives in moist environments, is gram-negative, motile, and an obligate aerobe.

Step 3: Eliminate other options. Meningococcus is a gram-negative diplococcus that causes meningitis and is a facultative anaerobe. Streptococcus pyogenes (Group A Strep) is a facultative anaerobe. Pneumococcus (Streptococcus pneumoniae) is also a facultative anaerobe. None of these is an obligate aerobe.

Step 4: Confirm the answer. Pseudomonas aeruginosa (Bacillus pyocyaneus) is an obligate aerobe, gram-negative, motile rod. It is a normal inhabitant of burns and surgical wounds, and under suitable host conditions, it can become a life-threatening pathogen causing invasive burn wound sepsis.

Answer: Pseudomonas aeruginosa