Which description accurately reflects Lawsonia intracellularis?

Which description accurately reflects Lawsonia intracellularis?

• A. Gram-positive cocci forming clusters
• B. Filamentous anaerobe with extracellular lifestyle
• C. Gram-negative slender curved rod, microaerophilic, obligate intracellular pathogen
• D. Spore-forming obligate aerobe

Answer: (C)

Lawsonia intracellularis is an obligate intracellular bacterium that causes proliferative enteropathy, mainly in pigs. It is described as a Gram-negative, slender curved rod, and it cannot be cultured on routine media because it must grow inside host cells. Its growth is favored in environments with reduced oxygen, often described as microaerophilic. This combination—Gram-negative slender curved rod, dependency on intracellular replication, and non-spore-forming nature—fits best with the description of an obligate intracellular pathogen rather than extracellular, Gram-positive cocci, filamentous anaerobe, or spore-forming aerobes.

Lawsonia intracellularis is an obligate intracellular bacterium that causes proliferative enteropathy, mainly in pigs. It is described as a Gram-negative, slender curved rod, and it cannot be cultured on routine media because it must grow inside host cells. Its growth is favored in environments with reduced oxygen, often described as microaerophilic. This combination—Gram-negative slender curved rod, dependency on intracellular replication, and non-spore-forming nature—fits best with the description of an obligate intracellular pathogen rather than extracellular, Gram-positive cocci, filamentous anaerobe, or spore-forming aerobes.