Which Enterobacteriaceae species is known for causing nosocomial infections?

• A. Escherichia coli
• B. Salmonella enterica
• C. Klebsiella pneumoniae
• D. Shigella dysenteriae

Answer: (C)

Klebsiella pneumoniae is particularly well-known for its role in nosocomial infections, which are infections acquired in healthcare settings. This organism can cause a variety of infections, including pneumonia, bloodstream infections, and urinary tract infections, particularly in patients who are hospitalized or have compromised immune systems.

Klebsiella pneumoniae has the ability to produce a thick capsule that aids in its virulence, allowing it to evade the host's immune response and adhere to surfaces within the body. Its association with invasive procedures, such as catheterization or ventilator use, further increases the risk of infection in hospitalized patients.

In contrast, while Escherichia coli can also cause healthcare-associated infections, it is more commonly known for causing community-acquired infections such as urinary tract infections. Salmonella enterica is typically associated with foodborne illnesses rather than nosocomial infections, and Shigella dysenteriae is primarily known for causing dysentery, particularly in uncontrolled environments rather than in hospitals. Thus, Klebsiella pneumoniae stands out as a prominent pathogen in the context of hospital-acquired infections.