Pt has hx of MRSA infection in this wound. .
 The patient has no history of infection. 
(ROOT (S (NP (NN Pt)) (VP (VBZ has) (NP (NP (NN hx)) (PP (IN of) (NP (NN MRSA) (NN infection)))) (PP (IN in) (NP (DT this) (NN wound)))) (. .) (. .)))
(ROOT (S (NP (DT The) (NN patient)) (VP (VBZ has) (NP (NP (DT no) (NN history)) (PP (IN of) (NP (NN infection))))) (. .)))
( Pt ( ( ( ( has ( hx ( of ( MRSA infection ) ) ) ) ( in ( this wound ) ) ) . ) . ) )
( ( The patient ) ( ( has ( ( no history ) ( of infection ) ) ) . ) )