For the past week, Susan has felt a burning sensation in the area of her urethra when she urinates. She checks her temperature and finds that she has a low-grade fever. What is likely occurring, and...

For the past week, Susan has felt a burning sensation in the area of her urethra when she urinates. She checks her temperature and finds that she has a low-grade fever. What is likely occurring, and what unusual substances are likely to be in her urine?