Another concern would be rabies.
http://pediatrics.about.com/od/weeklyquestion/a/0407_cat_bite.htm
"rabies - surprisingly,more reported rabies cases in the United States involve cats than dogs, although those cases are still much lower than the incidence of rabies in wild animals."
Probably a good idea to ask your neighbors if the cat is up-to-date on its vaccines.
In addition, the entire web link above (even for adults) has good info regarding cat bites, especially since you're immunosupressed.
Good luck,
Jan