<s>[INST] My partner has a catheter. Why don't they prescribe an antibiotic to prevent urine infection? [/INST] It is impossible to keep a probe in a sterile environment. Whether the use of antibiotics is necessary in this situation has been carefully studied, and evidence has been found that their use is counterproductive. They should be used only when the doctor treating the catheterised person deems it necessary: in the presence of an active urinary tract infection, which is different from a positive urine culture.  Source: Hospital Clinic Barcelona. Link: https://www.clinicbarcelona.org/en/assistance/diseases/urinary-tract-infection/frequently-asked-questions. Field: Urology. Disease: Urinary Tract Infection  </s>