How Can Chronic UTI Be Treated?

My 19 year old daughter is currently in the hospital;. She was diagnosed with a UTI during her last period a month ago which became very serious. She was moved from the emergency room to the ICU for 2 days. Symptoms were High fever (spiked up to 105) nausea, aches in her joints and her blood pressure dropped to 72 over 37. With lots of antibiotics and fluids her symptoms calmed and after 4 days she was released. She started her period this past Friday and Sunday she began vomiting and ran a low grade fever. Her white blood cell count which was normal on Friday (she was tested as a follow up) had jumped to 30,000 on Monday. She is in the hospital now receiving heavy antibiotics and fluids but her blood pressure is dropping again. It s presently 90 over 39. I am very concerned that there is more to this than a virus, which is the present assumption by the medical staff. The stiffness and joint pain is fairly severe. She can barely extend her arms above her shoulders. She said it feels just like it did a month ago which was diagnosed as a bacterial UTI that may have gone Sepsis or possibly Septic Shock. I am very concerned and just looking for other possible causes.