Antibiotics

• Patients may develop a continuing bladder infection because they do not take all of their antibiotics, according to MedlinePlus (See Reference 1). Medications that are used to treat bladder infections contain a specific number of doses, which are needed to kill bacteria causing the infection.
  
  

Kidney Infections

• A bladder infection will likely continue and become worse if it is left untreated because it will spread to the kidneys. Untreated bladder infections can cause pyelonephritis, a type of kidney infection that can cause major kidney problems, according to the Mayo Clinic (See Reference 2).
  
  

Diseases

• Sometimes patients with chronic and/or debilitating diseases, such as HIV, AIDS, cancer, sickle cell anemia or diabetes, develop a prolonged bladder infection because the diseases affect the ability of their immune system to function correctly.
  
  

Other Illnesses

• People who use catheters for long periods of time because of nervous system disorders are at risk for developing a prolonged bladder infection, according to the National Institute of Diabetes and Digestive and Kidney Diseases (See Reference 3). Kidney stones, an enlarged prostate and vesicoureteral reflux can cause a long-lasting bladder infection because they can disrupt the natural flow of urine.
  
  

Female Body

• Women who have gone through menopause have an increased risk of developing a continuing bladder infection because as they age, tissue in their vagina and bladder thins. Hormonal changes cause pregnant females to have an increased risk of developing a prolonged bladder infection.