Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which organism is frequently associated with central line infections?

1. Staphylococcus Epidermidis

2. Escherichia Coli

3. Klebsiella Pneumoniae

4. Streptococcus Pneumoniae

The correct answer is: Staphylococcus Epidermidis

Staphylococcus epidermidis is a coagulase-negative staphylococcus that is well-known for its role in central line infections. This organism is part of the normal skin flora but can become pathogenic, especially in immunocompromised patients or those with indwelling medical devices. Central venous catheters (central lines) provide a direct route for bacteria to enter the bloodstream, and because Staphylococcus epidermidis is adept at forming biofilms on the surfaces of these devices, it often causes infections that are difficult to treat. The other organisms listed are associated with infections but do not have the same strong link to central line infections as Staphylococcus epidermidis. Escherichia coli and Klebsiella pneumoniae are more commonly associated with urinary tract and intra-abdominal infections. Streptococcus pneumoniae is primarily known for respiratory infections, such as pneumonia and meningitis, rather than healthcare-associated infections related to central lines. Thus, Staphylococcus epidermidis is recognized specifically for its frequent association with infections related to central venous catheters.