Use the following choices to answer questions 2–5:
a. Candida
b. Chlamydia
c. Gardnerella
d. Neisseria
e. Trichomonas
Microscopic examination of vaginal smear shows gram-negative cocci in phagocytes.

Verified step by step guidance

Step 1: Identify the key observation in the problem, which is the presence of gram-negative cocci inside phagocytes in a vaginal smear. This indicates that the bacteria are being engulfed by immune cells, suggesting an active infection.

Step 2: Recall the characteristics of the organisms listed: Candida is a fungus, Chlamydia is an obligate intracellular bacterium but not typically seen as gram-negative cocci, Gardnerella is a gram-variable rod, Neisseria is a gram-negative diplococcus, and Trichomonas is a protozoan parasite.

Step 3: Understand that gram-negative cocci inside phagocytes are characteristic of Neisseria species, particularly Neisseria gonorrhoeae, which is known to infect the genital tract and appear as gram-negative diplococci within neutrophils.

Step 4: Use the process of elimination based on morphology and staining: since the problem specifies gram-negative cocci and their presence inside phagocytes, Neisseria is the most appropriate choice.

Step 5: Conclude that the microscopic finding corresponds to Neisseria, which is consistent with the clinical presentation of gonorrhea, a common sexually transmitted infection.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Gram Staining and Bacterial Morphology

Gram staining differentiates bacteria into gram-positive or gram-negative based on their cell wall structure. Gram-negative bacteria appear pink/red under a microscope and have a thin peptidoglycan layer. Cocci are spherical bacteria, and identifying their shape and gram reaction helps narrow down the bacterial species.

Phagocytosis and Intracellular Bacteria

Phagocytes are immune cells that engulf pathogens. Finding bacteria inside phagocytes indicates the organism can survive or be detected within host immune cells. This helps identify pathogens like Neisseria, which are known to be gram-negative cocci found inside phagocytes in infections.

Common Vaginal Pathogens and Their Characteristics

Different pathogens cause vaginal infections, each with distinct features: Candida is a fungus, Chlamydia is an intracellular bacterium, Gardnerella is a gram-variable rod, Neisseria gonorrhoeae is a gram-negative diplococcus found in phagocytes, and Trichomonas is a protozoan. Recognizing these traits aids in diagnosis.

Recommended video:

Guided course