Certification Board of Infection Control and Epidemiology (CBIC) Practice Exam 2026 – The All-in-One Guide for Exam Success

Bullous impetigo is primarily related to Staphylococcus aureus, particularly the strains that produce toxins that lead to the characteristic vesicular (blistering) lesions associated with this condition. Staphylococcus aureus is a common cause of skin infections, and its strains can lead to both non-bullous and bullous forms of impetigo. The bullous form, in particular, is distinguished by larger, fluid-filled blisters that can easily rupture, leading to the classic honey-colored crust seen in this type of skin infection.

The other bacteria listed are associated with different clinical conditions. Group A streptococcus is known for causing pharyngitis, cellulitis, and other forms of skin infection but is rarely the cause of bullous impetigo. Enterococcus faecalis is primarily involved in enteric infections and is not associated with skin infections like impetigo. Clostridium difficile is known for causing antibiotic-associated diarrhea and colitis and has no direct link to skin conditions such as impetigo. Thus, Staphylococcus aureus is correctly identified as the primary bacterium responsible for bullous impetigo.