## Core Concept
Chlamydia trachomatis is a gram-negative, obligate intracellular bacterium that causes various infections, including sexually transmitted infections (STIs) and trachoma. It has a unique life cycle involving two main forms: the infectious elementary body (EB) and the replicative reticulate body (RB). Understanding its characteristics is crucial for diagnosing and managing infections.

## Why the Correct Answer is Right
The correct answer, which is not provided, would relate to a statement about Chlamydia trachomatis that is not true. Typically, true statements might include its role in causing STIs, its obligate intracellular nature, and its unique life cycle. Without the specific statements, we focus on general principles that could make one option incorrect.

## Why Each Wrong Option is Incorrect
- **Option A:** Without specific details on each option, we consider a hypothetical scenario where option A might state something like "Chlamydia trachomatis can be cultured on routine bacterial media." This would be incorrect because Chlamydia trachomatis is an obligate intracellular pathogen that requires cell culture or specialized media for growth, not routine bacterial media.
- **Option B:** If option B claims "Chlamydia trachomatis infections are often asymptomatic," this would generally be true, especially in women, making it not the incorrect statement we're looking for.
- **Option C:** If option C mentions "Chlamydia trachomatis is a common cause of sexually transmitted infections worldwide," this is true and not the incorrect statement.
- **Option D:** If option D suggests "Chlamydia trachomatis can be effectively treated with penicillin," this would be incorrect because Chlamydia trachomatis is not effectively treated with penicillin; azithromycin and doxycycline are commonly recommended.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **Chlamydia trachomatis** infections are often asymptomatic, particularly in women, which can lead to undiagnosed and untreated infections, potentially causing complications like pelvic inflammatory disease (PID). Screening for Chlamydia is recommended for sexually active women aged 25 and younger.

## Correct Answer: D.