A. This is either an infection that isn't responding to this specific antibiotic or more probably a bladder inflammation.
Bladder inflammation (FLUTD) is a common condition in cats, it is caused by stressful situation (could be a new pet in the house, new human, new neighbor, an aggressive cat outside...). This causes an inflammation of the bladder (the mechanism is not fully understood) and so the bleeding begins.
The treatment is to remove the stress factor if possible, give the cat calming agents (EX. Feliway diffuser), and supportive treatment with Cystophan, special urinary food and bladder muscles relaxants (valium and prazosin.).
You will need to go back to the vet as the antibiotic treatment is not enough in this case.
A. Have her rechecked by your veterinarian. The infection may not have been completely resolved. Have your vet collect a sterile urine sample for a culture and sensitivity panel. This test should identify the bacteria responsible as well as the most effective antibiotic to use in treatment. You may need to treat for more than 2 weeks. A repeat urine culture afterwards is crucial in confirming resolution. Rule out other causes such as bladder or kidney stones. This can be done with an abdominal xray in most cases.
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