instruction: Given a reference text about the adverse affects of Foley catheters, please list the main risks.
context: Catheterized bladders become colonized by microorganisms very quickly, with a daily incidence of 3-10%; after four days, between 10-30% of patients develop bacteriuria. Whilst the presence of a catheter does increase the incidence of bloodstream infections secondary to a urinary origin, there is a huge amount of unnecessary, and likely harmful, antimicrobial prescribing on the basis of detection of asymptomatic bacteriuria. The industry is moving to silver-coated catheters in an attempt to reduce the incidence of urinary tract infections, although there is limited evidence of efficacy. An additional problem is that Foley catheters tend to become coated over time with a biofilm that can obstruct the drainage. This increases the amount of stagnant urine left in the bladder, which further contributes to urinary tract infections. When a Foley catheter becomes clogged, it must be flushed or replaced. There is currently not enough adequate evidence to conclude whether washouts are beneficial or harmful.
  https://en.wikipedia.org/wiki/Foley_catheter
response: The risks of a Foley catheter include urinary tract and bloodstream infections. In addition, overprescribing of medications to treat infections leads to what is likely additional risk.