Antibiotics for Urinary Tract Infections – Emerging Resistance

January 23, 2021

Antibiotics are a great way to fight bacterial infection, saving many lives since their discovery by Sir Alexander Fleming in the early part of the last century. Unfortunately, evolution mitigates against their effectiveness after a number of bacterial generations. Like all living things, bacteria have mutations, or changes in DNA. Some of these changes confer resistance to certain antibiotics, making these antibiotics harmless to given strains of bacteria. This is why the use of antibiotics should be limited only to likely bacterial infections.

Urinary tract infections were successfully treated with ampicillin for a number of years, until Escherichia coli and its relatives, the chief causative bacteria, developed resistance. Then Bactrim (trimethoprim and sulfamethoxazole) became the mainstay of treatment. In 1999 the Journal of General Internal Medicine published a study of 448 patients seen for urinary tract infections in an emergency room. A total of 15 per cent had bacteria resistant to Bactrim. In 2018 the Journal of Microbial Chemotherapy published a study showing resistance to trimethoprim in 28% of bacteria found in urinary tract infections in children. The article went on to document resistance to the antibiotic Augmentin (co-amoxiclav), and a combination of drugs. 43% of the bacteria were resistant to at least one type of antibiotic. UTIs can of course be caused by lots of different bacteria, in all of which we see the same concerning development as with E. coli.

Which antibiotics are prescribed may depend on local and regional resistance patterns. Therefore, if a treatment with antibiotics is not effective, a different antibiotic may be needed and a urine culture can be obtained to see which bacteria is causing the infection, and what the bacteria is resistant to.

Antibiotics for UTI:

These are the most commonly prescribed antibiotics for urinary tract infections:

  • Macrobid (nitrofurantoin)
  • Keflex (cephalexin)
  • Ciprofloxacin
  • Bactrim
  • Levofloxacin

Future development:

Research is aimed at immunizations against urinary tract infections—especially for patients with recurrent infections—but their practical use is some time down the road. In the meantime, try to prevent urinary tract infections by drinking plenty of water and practicing good hygiene. Only request antibiotics when they are truly needed and if your doctor feels you do not need them, remember, that they want the best for you. Antibiotics won’t do a thing for viral infections, and will only help to grow bacteria with resistance in you and have side effects like diarrhea and changing your gut flora.


Did you know? QuickMD can treat urinary tract infections from the comfort of your own home, and we can prescribe antibiotics for your UTI online. Want to order your own urine testing? You can order your own labs here.

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