革兰氏阳性球菌引起的感染性心内膜炎颇多,而革兰氏阴性细菌感染性心内膜炎却很少报道,形成鲜明的对比。考虑到泌尿生殖道及肠道感染或操作导致革兰氏阴性菌血症的机会很多(且这些病人主要为常有动脉粥样硬化或心瓣膜疾病的老年人),伤寒病人均有菌血症,沙门氏菌胃肠炎亦常有细菌侵入血液,而发生心内膜炎者罕见,这就更为突 Gram-positive cocci cause a lot of infective endocarditis, and Gram-negative bacterial endocarditis are rarely reported, in stark contrast. Taking into account the genitourinary tract and intestinal infections or the operation has a great chance of causing Gram-negative bacteremia (and these patients are mainly elderly people with atherosclerosis or heart valve disease), the typhoid patients have bacteremia , Salmonella gastroenteritis bacteria often invade the bloodstream, and the occurrence of endocarditis are rare, which is even more sudden