Final answer:
If the nurse touches the IV tubing insertion spike, the best action is to discard the tubing and obtain a new one to maintain sterility and ensure patient safety.
Step-by-step explanation:
When the nurse is preparing an IV infusion and contamination of the tubing insertion spike occurs by accidental touch, the most appropriate action to maintain sterility is option C: Discard IV tubing and obtain a new one. Touching the spike compromises the sterility of the system, therefore using an alcohol swab as suggested in option A is not acceptable in this scenario as it does not ensure complete sterility. The integrity of both the IV tubing and fluids are essential for patient safety, and while option D mentions discarding both the tubing and fluids, this is only necessary if the fluids were also compromised. In this case, since only the spike was touched, only the tubing needs to be replaced.