What is the most common source of patient infection in the operating room?

The most common source of patient infection in the operating room is the patient's own endogenous flora. This refers to the naturally occurring bacteria and microorganisms that live on and within the patient's body. During surgical procedures, especially when incisions are made, these microorganisms can enter sterile areas and potentially lead to postoperative infections.

Endogenous flora can be a significant risk factor for surgical site infections because the body’s normal microbial colonies, which are typically harmless, may become pathogenic once there is an opportunity for them to enter deeper tissues or enter the bloodstream. This transition from being harmless to potentially harmful can occur if the skin and mucosal barriers are compromised during surgery.

Other sources of infection, while important, are generally less common than endogenous flora. For instance, the surgical team adheres to strict protocols to minimize their role in infection transmission, environmental surfaces are regularly cleaned, and instruments are sterilized to reduce contamination risk. However, because the patient's own flora is always present, it poses a more pervasive risk during surgery, especially if the correct measures aren’t taken to prevent their introduction into sterile sites.