Impetigo -- again....ARG!

To all you fabulous Peds nurses out there.....

my 3 y.o daughter is experiencing her 5th outbreak of impetigo since she was 2. It's on her left nostril this time (been here once before) and was on her lower lip 2 weeks ago, we also had a vesicle come up on her index finger last year..... little more Hx: my husband is also very susceptible to skin infections, had impetigo a lot as a kid, drove my MIL crazy

of course this comes up Friday afternoon, can't make it to the pediatrician, and don't really think this warrants 8+ hours in our level 2 ED in town, so we slap on the Bactrim ointment and try to keep it covered with a band-aid and wash hands like crazy....the spots are small this time ~0.5 cm X 3

So I guess what I am mostly curious about is:

1) as a nursing student with tons of books and internet access, I know this is very common with toddlers, am I over-concerned that it recurred 2 weeks after a ped. visit and 10 days of sulfa-ABX?

2) do I need to request culture and sensitivity when we go back monday to see what bacteria we're dealing with?

3) Is she harboring this creature or are we picking this bug up somewhere?

BTW, she stays home, no daycare.....

Any help anyone could lend would be great...I know impetigo is really "no big deal", but I understand the rarity of glomerulonephritis, we are watching the "tee-tee" but if she's contagious that means no playground, and that's like telling her not to breathe!

thanks, I take Peds next semester :)