what is quellung test all about, which organisms are positive for?

Answer 1

I guess it is used for people.

" Neu·feld capsular swelling (noi'fĕlt)
n.

An increase in the opacity and visibility of the capsule of encapsulated organisms resulting from exposure to specific, agglutinating, anticapsular antibodies. Also called Neufeld reaction, quellung phenomenon, quellung test."
http://www.answers.com/topic/neufeld-capsular-swelling
http://www.biology-online.org/dictionary/Quellung_test