What is the drug of choice for E. coli UTIs, given the resistance to Amoxicillin?

The drug of choice for Escherichia coli urinary tract infections (UTIs), particularly in the context of resistance to Amoxicillin, is Trimethoprim. This is due to its effectiveness against E. coli, which is a common pathogen in urinary infections.

Trimethoprim inhibits bacterial synthesis of folate, which is essential for their growth. It has good oral bioavailability and achieves adequate concentrations in the urine, making it particularly suitable for treating UTIs. The growing resistance to Amoxicillin, a penicillin-type antibiotic, makes it less effective against E. coli infections.

Other options, while they may have some effectiveness, are not considered first-line treatments in this specific scenario. Augmentin, which combines amoxicillin with clavulanic acid, may not be effective against resistant E. coli strains. Ceftriaxone is a cephalosporin antibiotic typically reserved for more severe infections or those requiring intravenous treatment due to its broader spectrum. Metronidazole is indicated for anaerobic infections and protozoal infections but is not typically used for UTI caused by E. coli.

Thus, Trimethoprim is favored for empirical treatment of uncomplicated UTIs when there is concern about bacterial resistance to first-line