患者，男性，43岁，3个月前出现发作性头痛，为左侧枕部尖锐、针刺样疼痛，可自行缓解，伴言语不清，右侧上肢麻木。头颅CT示左侧颞叶出血合并左侧蛛网膜下腔少量出血，头颅数字减影血管造影示左侧颈内动脉虹吸部动脉瘤可能性大。1个月前患者出现间断发热，体温最高39 ℃，20天前再次出现头痛，疼痛部位、性质、持续时间、缓解方式均较前相似。内科系统查体：心尖区可闻及收缩期2/6级吹风样杂音。神经系统查体：右侧Babinski症（+）。住院第4天超声心动图发现二尖瓣前叶赘生物，考虑感染性心内膜炎菌栓脱落导致脑栓塞，立即给予万古霉素治疗。住院期间3次血培养均阴性，采血标本送至中国疾病预防控制中心传染病预防控制所，行间接免疫荧光法IgG抗体检测，结果提示汉赛巴尔通体IgG抗体阳性，因此，临床诊断考虑汉赛巴尔通体感染所致感染性心内膜炎并发蛛网膜下腔出血和脑栓塞。巴尔通体是一种需要复杂营养的细胞内革兰氏阴性杆菌，1993年首次作为导致心内膜炎的原因被记载，此后作为血培养阴性感染性心内膜炎的一个重要病原体日益得到公认。对于明确的巴尔通体心内膜炎, 美国传染病协会指南建议2周的庆大霉素联合6周的强力霉素治疗，以获得更高的治愈率。

The patient, a 43-year-old man, had paroxysmal headache three months ago, and he had complained the left occipital sharp pain, which could be alleviated by itself, with alalia and the right side of the upper limb numbness. Head computed tomography (CT) revealed a left temporal lobe intraparenchymal hemorrhage with the left side of the subarachnoid hemorrhage in small quantities. Digital subtraction angiography (DSA) revealed a suspicious aneurysm on the left internal carotid artery siphon. He had intermittent fever 1 month ago, with maximum body temperature 39 ℃. He suffered headache again 20 days ago, with pain nature, duration and the way of easing up similar to the earlier onset. General examination demonstrated 2/6 grade blowing systolic murmurs at apex area. Neurological examination revealed that Babinski’s sign was positive on the right side. Echocardiographic found an anterior mitral valve ve-getation on the 4th day in hospital. So his clinical diagnosis was infective endocarditis with cerebral embolism. He received vancomycin treatment immediately. His three blood cultures remained negative in hospital. His blood specimens were sent to Chinese Center for Disease Control and Prevention, indirect immunofluorescence method (IFA) IgG antibody detection revealed that the Bartonella henselae IgG antibody was positive. Therefore the clinical diagnosis was Bartonella endocarditis complicated with subarachnoid hemorrhage and cerebral embolism. Bartonella, an intracellular fastidious, gram-negative bacilli, was first documented as a cause of endocarditis in 1993 and since then has been increasingly recognized as an important etiology of infective culture-negative endocarditis. In cases of documented Bartonella endocarditis, the Infectious Diseases Society of America (IDSA) guidelines recommended 2 weeks of gentamicin plus 6 weeks of doxycycline treatment, to achieve a higher cure rate.