This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
In a surgical patient, the causes of non surgical infection are all, except 
Select and explain. 
A. Lower respiratory tract infection, B. Wound infection, C. Clostridium difficile diarrhea, D. UTI
B: Wound infection
Answer: B: Wound infection 
Explanation: Surgical site infections (SSIs)  are the third most frequently reported nosocomial infection, first one being pneumonia and the second,  catheter-related  (including urinary  tract infection).
SSI within 24 hours is caused by clostridia and streptococci.
SSI  after 48  hours  (5  days)  is  caused  by  gram -ve  and other  bacteria.
Clostridium diﬃcile diarrhea occurrence is due to administration of various antibiotics.

​Reference:  Manipal Manual of Surgery 4th ed page no 26, 28