Erythromycin

I grew-up in a family that tended to overuse medicines--treated the first symptoms of an affliction without waiting to see if the body's own immunity might prevent illness from taking hold. The overuse of antibotics first by my mother and, more recently, the tendency of my physician to use them to treat even minor infections has left me a little gun shy. Also, I have read numerous studies, which suggest overuse of antibiotics can weaken immunity--though results vary about the extent of their affect. Still, I believe these drugs should be used when they are truly needed, but only under those circumstances.

My son, who is now 34 gestational weeks old began developing a very light mucousy condition a few days ago. Notably, we originally refused erythromycin right after he was born. To examine the condition, his eye was swabbed and the material cultured, with results indicating there was "no obvious infection", but he was "at risk for infection". The doctors began using erythromycin right away and a day later all of the mucousy material appeared to be gone, he is now on his third day of treatment. I'd like to discontinue this treatment immediately to limit his exposure to the drug--especially after considering his age and the quickly developing ability of his tear ducts to naturally deal with infection. The doctor, on the other hand, has demanded he remain on the treatment for an entire week, arguing it is standard practice.

I understand the medical standard is six to eight days of treatment, but is this necessary? If the infection appears gone why should he be treated for an additional four days? Is there a reasonable way to shorten the treatment or at decrease the dosage? If the infection was affecting only one eye, is it necessary to treat the other?