Vitamin D deficient?

Reading this forum has certainly opened my eyes to more than 'just' a deficiency.  I was diagnosed with MRSA about 6 months ago, and underwent a barage of antibiotic treatments. Doxycycline, 10 days, Septra DS,2 tabs twice daily 10 day, Levoquin 750 mg 10 days.  I am concerned that this insult to my system may be the cause of my deficience. Living near the ocean , I do spend lots of time in the outdoors.  My home life also encourages outdoor living.  I take very few medications, eat well and take vitamins and minerals.  I am infrequently sick.  Last time was 3 years ago. How does antibioti treatment actually affect Vitamin D in the body?