What is the difference between the antibiotic Bactrim and the antibiotic nitrofurantoin

I was diagnosed with a bladder infection. One doctor prescribed me Bactrim and another doctor prescribed me with nitrofurantoin?

Bactrim is in the classification of anti-infectives called sulfonamides and is a combination of sulfamethoxazole and trimethoprim called co-trimoxazole. It's used to treat UTIs caused by strains of E. coli, Proteus, Klebsiella or Enterocobacter.

Nitrofurantoin (Macrobid, Macrodantin) is a miscellaneous anti-infective, no specific calssification, and is also used to treat UTIs caused by E. coli, certain strains of Klebsiella and Enterocobacter and also Staph a. and enterococci.

If you had a urine culture and the organism was identified as E. coli, Kelbsiella or Enterocobacter, then either one will work. Find out what is causing the infection.