Final answer:
Among the given options, a wound culture is the most definitive indicator of a bacterial infection as it allows for specific identification and effective treatment.
Step-by-step explanation:
Indicators of a bacterial infection can include a fever, an increase in White Blood Cell (WBC) count, an elevated sedimentation rate (sed rate), and the results of a wound culture. Fever is a common systemic response to infection. An increased WBC count occurs because the body is producing more white blood cells to fight off infection. The sed rate may increase due to inflammation caused by the infection. However, the most definitive indicator among the options provided is a wound culture, which allows for the specific identification of the bacteria causing an infection, critical for choosing the appropriate treatment or antibiotics. Indeed, the cases described such as Cindy's wound and Roberta's urinary symptoms, support the use of cultures together with blood work for accurate diagnosis and treatment of bacterial infections.