Chapter 18.L2, Problem 1CT

You have been handed the problem of diagnosing gonorrhea from a single test. Which one will you choose and why?

Summary Introduction

To analyze:

Which diagnostic test is to be used, if gonorrhea must be diagnosed using one test only.

Introduction:

Gonorrhea is caused by a Gram negative bacterium - Neisseria gonorrhoeae. There is a need to differentiate it from other Gram negative bacteria during diagnosis.

Explanation of Solution

N. gonorrhoeae can be identified by a series of differentiating tests, beginning with the Gram stain, followed by analysis of oxidase production, sugar fermentation, growth patterns, nitrogen reduction and pigment production. However, more rapid methods are preferred for early diagnosis.

One property of this pathogen that allows a reasonably accurate diagnosis is that it tends to get engulfed by phagocytes, and remain viable in them. So collecting neutrophils from the urethra, vaginal, or exudates from the eyes of any of aforementioned parts, and performing a Gram stain to identify Gram-negative diplococci is a single test that can diagnose gonorrhea.

To identify N. gonorrhoeae with high precision in a single test, PCR analysis is used on urine samples.

Conclusion

A Gram stain on neutrophils from the urethra, vaginal, or exudates from the eyes of any of aforementioned part, to identify Gram-negative diplococci, can diagnose gonorrhea with reasonable accuracy.