NCLEX Review Guide: Adult Infectious Diseases - MRSA, VRE, and C. difficile

Key Characteristics and Transmission

• MRSA is a gram-positive bacteria resistant to methicillin and other beta-lactam antibiotics, commonly found in healthcare settings and community environments.
• Transmission occurs through direct contact with infected wounds, contaminated hands, or contaminated surfaces, making hand hygiene the most critical prevention measure.
• High-risk populations include immunocompromised patients, those with chronic wounds, indwelling devices, or prolonged antibiotic use.

Pathophysiology and Risk Factors

• VRE is a gram-positive bacteria that has developed resistance to vancomycin, typically affecting the urinary tract, bloodstream, and surgical sites.
• Major risk factors include prolonged hospitalization, intensive care unit stay, immunosuppression, and previous antibiotic exposure, particularly vancomycin and broad-spectrum antibiotics.
• VRE colonization in the GI tract can persist for months and serves as a reservoir for transmission to other patients.

Pathogenesis and Clinical Presentation

• C. diff is a spore-forming, gram-positive anaerobic bacteria that causes antibiotic-associated colitis when normal gut flora is disrupted.
• Clinical presentation ranges from mild diarrhea to life-threatening pseudomembranous colitis with toxic megacolon, characterized by watery, foul-smelling stools.
• Spores are highly resistant to alcohol-based sanitizers and most disinfectants, requiring soap and water handwashing and bleach-based cleaning solutions.

C. diff Management Protocol

1. Discontinue inciting antibiotics immediately if clinically appropriate
2. Initiate contact precautions with private room and dedicated equipment
3. Start oral vancomycin or fidaxomicin for severe cases
4. Monitor for complications: toxic megacolon, perforation, sepsis
5. Consider fecal microbiota transplantation for recurrent infections