(S (S (NP (BASENP (NN Staphylococcus) (NN aureus)) (PRN (COMMA ,) (VP (ADVP (RB commonly)) (VP (VBN known) (PP (IN as) (BASENP (NN staph))))) (COMMA ,))) (VP (VBZ is) (NP (BASENP (DT a) (NN bacteria)) (SBAR (WHNP (WDT that)) (S (VP (ADVP (RB commonly)) (VP (VP (VBZ causes) (BASENP (NN skin) (NNS infections))) (PP (IN in) (BASENP (ADJP (RB otherwise) (JJ healthy)) (NNS people)))))))))) (PERIOD .))