Final answer:
The priority nursing action is to contact the health care provider due to signs of potential infection, with immediate medical attention required.
Step-by-step explanation:
The priority nursing action when monitoring a newborn infant who has been circumcised and is displaying symptoms such as a fever of 100.6° F and foul-smelling drainage at the dressing site is c) Contact the health care provider. These symptoms suggest a potential infection, and prompt medical attention is required to treat any possible complications.
The infant's condition warrants immediate communication with a health care provider to determine the appropriate interventions, which may include antibiotic treatment and further medical evaluation. While reinforcing the dressing (option a) and swabbing for a culture (option d) could be subsequent actions, and documenting the findings (option b) is part of the process, they are secondary to the immediate need to seek medical intervention. It is crucial to recognize the signs of a potential infection and act swiftly to ensure the health and safety of the newborn.