Experience of UTI 6 weeks following anterior resection and antibiotics causing nausea and diarrhoea. Anyone else go through this?

My husband developed had stinging on peeing following his anterior resection  He saw the surgeon who said this was to be expected. He now has a urinary infection and had IV antibiotics yesterday in A&E followed by Nitrofuradentoin orally. This is causing diarrhoea and nausea and he is feeling miserable. Has anyone else had this experience following this surgery. He does not have a stoma and would appear to have healed well  The resected specimen has clear marginx so that's all good news but between bowel issues and now husband's urinary infection  there does not seem to be any respite for him. Any similar experience stories and resolution would be comforting.