I would first check with your vet to make sure that the pH of the urine is where it is supposed to be. Normal is anywhere from 6.2-6.5. You can also test the urine at home with pH test strips you can get at health food stores. If the pH of the urine is too high it can contribute to vaginitis and UTI's. I would not be comfortable keeping a puppy on antibiotics either, maybe you could get a second opinion also...
One option that is listed in "The Veterinarians' Guide to Natural Remedies for Dogs", by Martin Zucker is using a combination of the amino acid methionine and cranberry extract, both found in health food stores.
*Methionine: Give 2x daily. Small and med dogs, 100 mg each time; larger dogs, 200 mg. If the urine is not acidic on two doses of methionine, increase to three times.
*Cranberry extract: Give 3x daily. Small dogs, 100mg each time; medium dogs 200mg; large dogs 300mg; giant breeds, 400 mg
Bonnie ~ Ellsworth Labradors
Home to Ellsworth's Playing For Keeps CGC, U-CH SHR Ellsorth's Absolut Pleasure, Ellsworth's Good Luck Charm
Gone but not forgotten: Franklin's Lucy of Ellsworth; Franklin's Rare Treat; U-CD Franklin's Rockin' Robin CDX, WC, CGC; Alpha-Omega's Mustang Salli CDX, CGC