Microbiology Pseudomembranous colitis is caused by: September 2005, 2010 & 2011 A Pneumocystis carinii B Clostridium difficile C Escherichia coli D Streptococcus pneumoniae 💡 Explanation Pseudomembranous colitis is caused by: September 2005, 2010 & 2011 ✓ Correct Answer: B. Clostridium difficile