Certification Board of Infection Control and Epidemiology (CBIC) 2025 – 400 Free Practice Questions to Pass the Exam

Enterococcus species are classified as facultative gram-positive cocci because they have specific characteristics that fit this classification. As gram-positive organisms, Enterococcus species retain the crystal violet stain used in gram staining, which results in a purple coloration under a microscope. This characteristic is due to their thick peptidoglycan layer in the cell wall.

Additionally, being facultative means that these organisms can grow in both aerobic and anaerobic environments, allowing them flexibility in different conditions. This adaptability is vital since Enterococcus can often be found in various environments, including the human gastrointestinal tract, where oxygen levels can fluctuate.

Understanding the classification of Enterococcus is critical in infection control, as their properties influence how they survive in hospital settings, their resistance to antibiotics, and their overall role in various infections.