Question

A truck driver comes with complaints of a painless indurated genital ulcer after unsafe intercourse. Which of the following investigations can be used to diagnose the causative organism?

• A. Dark Field microscopy
• B. HSV 2 antibody
• C. Albert Stain
• D. Acid-fast Stain

Hint:

For the diagnosis of chancroid, Dark Field microscopy is the gold standard. It is used to identify Haemophilus ducreyi by observing the bacteria in fluid from the ulcer.

Answer 1

The Correct Option is A

A painless, indurated genital ulcer is characteristic of Haemophilus ducreyi, the causative agent of chancroid. The most effective diagnostic method for chancroid is Dark Field microscopy. This method is used to visualize the causative organisms from a sample taken from the ulcer. The organisms appear as gram-negative coccobacilli, and this method allows for a quick, direct visualization of the bacteria. In contrast, HSV 2 antibody testing is used to diagnose herpes simplex virus infections, which present with painful genital ulcers, not painless ones. The Albert stain and Acid-fast stain are used to detect other organisms, such as Corynebacterium and Mycobacterium species, respectively, but are not suitable for diagnosing chancroid.