(S (S (S (BASENP (NNS Doctors)) (VP (VBP have) (VP (ADVP (RB already)) (VP (VP (VBN battled) (PP (IN for) (BASENP (NNS years)))) (PP (IN against) (NP (BASENP (JJ drug-resistant) (NNS strains)) (PP (IN of) (BASENP (DT the) (NNS bacteria))))))))) (CONJP (COMMA ,) (CC but)) (S (BASENP (DT the) (NN struggle)) (VP (VBZ has) (VP (ADVP (RB generally)) (VP (VBN been) (VP (VBN confined) (PP (TO to) (BASENP (NNS hospitals))))))))) (PERIOD .))