How do I get rid of a persistent fungal toe nail infection?

Laser treatment. The best treatment is laser with topical bid, steri shoe for all shoe gear.
See below. See a doctor for either oral medication, removal of the nail, or laser treatment.
TREATMENT OPTIONS. First, is it fungus? Other infections can cause the same appearance; a yeast, for example. A doctor should test for fungus. Then, there are topicals and orals, the most popular being terbinafine for 3 months. I quote 70% success w/ pills. Need bloodwork to check your liver. Be careful with statins; coordinate w/ your PCP. I find topicals very disappointing. Old wive's tale-Vicks Vaporub. Dr. Latva.
Many ways... Topical solutions, oral medications, laser treatments, surgical removal, homeopathic remedies, etc. The most used treatment is oral Lamisil (terbinafine) tablets once daily for 90 days. See a podiatrist for what may be best for your specific needs and expectations. Tea tree oil is one of the home remedies that has been shown to work and some have tried Vicks vaporub.
Seebelow. The most effective treatment is oral terbinafine, taken for 6 weeks for fingernail infections, and 12 weeks for toenail infections.