My 6 year old has a history of vesicoureteral reflux and has had corrective surgery over 2 years ago. The last 7 months she has had symptoms of a UTI, fever, body aches, and urine analysis comes back with WBC elevated enough to diagnose as UTI but then the culture doesn't grow anything. 3 weeks ago she had a 107 fever, body aches, tested pos. for UTI then started diarrhea, vomiting. tested neg. for strep, neg for flu and blood and urine analysis show bacterial infection but neither cultures grew anything. What could be going on?