Which of the following statements about diagnosing pneumonia in nursing home residents are true?

The statement regarding urinary antigen tests for Streptococcus pneumoniae remaining positive even after treatment is accurate. These tests are designed to detect specific antigens from the bacteria in the urine and can remain positive for some time following the initiation of antibiotic therapy. This persistence is due to the fact that the antigens may continue to be present in the urine even if the infection is being effectively treated, thereby making this test useful for diagnosis even after treatment has begun.

In contrast, other statements such as those regarding the role of chest X-rays and cough are not supported by clinical practice. Chest X-rays are a valuable diagnostic tool for pneumonia, as they can help visualize consolidation in the lungs and provide evidence of infection. A cough, while a common symptom of pneumonia, is not a definitive method for diagnosis since many respiratory conditions can produce similar symptoms. As for urinary antigen tests after treatment, they do not become negative immediately after antibiotics are administered, thus the reasoning regarding their continued positivity is crucial in understanding the diagnostic process in nursing home residents with pneumonia.