A 70 year old lady of recurrent ischaemic stroke on a chronic urinary catheter presented with purple discoloration of her catheter bag. Clinically, she was febrile. The urinary catheter drainage bag (Panel A) was purple stained. Her urine pH was alkaline at 7.5 with leucocytes present. The urine culture grew Klebsiella pneumoniae. She was treated with ampicillin/sulbactam which led to the resol...