Which of the following organisms can penetrate an intact cornea?

Haemophilus influenzae is capable of penetrating an intact cornea, primarily due to its virulence factors and ability to cause acute infections. It is a small, non-motile, Gram-negative bacillus that can adhere to and invade epithelial cells. When it does penetrate the cornea, it can lead to conditions such as keratitis. This organism is particularly adept at causing infections in immunocompromised patients or those with pre-existing ocular conditions, which can facilitate its entry through the cornea.

Other organisms, while they can be associated with ocular infections, typically require some form of disruption to the corneal surface for penetration. For example, Staphylococcus aureus and Staphylococcus epidermidis are usually found in association with compromised skin or mucous membranes. Thus, they generally do not penetrate an intact cornea without prior injury. Similarly, Salmonella enterica is primarily associated with gastrointestinal infections and does not penetrate healthy corneal epithelium under normal circumstances. Therefore, Haemophilus influenzae stands out as the organism most likely to penetrate an intact cornea.