What is the best antibiotic for a UTI?

Let’s start with some basics.

What is a UTI?

A urinary tract infection (UTI) is an infection in any part of the urinary tract (system). The system includes the kidneys, ureters, bladder and urethra (and prostate in a man).

Urinary tract

So. What is the best antibiotic for a UTI?

There is not one single ‘best’ one. But these 5 antibiotics are commonly used (and are effective) for uncomplicated urinary tract infections (UTIs):

Combination antibiotics – e.g.
- Cotrimoxazole (‘Septrin’; trimethoprim and sulfamethoxazole)
- Amoxicillin/clavulanic acid (Augmentin)
Trimethoprim
Penicillins – e.g. amoxycillin
Cephalosporins – e.g. cephalexin
Nitrofurantoin.

Other antibiotics

Fluoroquinolones – e.g. ciprofloxacin, now rarely used.

What bacteria cause UTIs?

The most common bacterium is Escherichia coli (in 70 to 95% of cases)
Less commonly organisms include Staphylococcus saprophyticus (approximately 5-10% of cases), Proteus mirabilis (more common in males, associated with urinary tract abnormalities, particularly stones), and Klebsiella species.

Other resources

CKD patient information (CKDEx’s 30+ core articles about CKD)
What is a UTI?
10 UTI facts
10 recurrent UTI facts

Last Reviewed on 20 April 2024