Infective endocarditis in paediatrics

Infective endocarditis is a result of infection of the endocardium, particularly of the heart valves (native or prosthetic valves). The most common causative organisms in the paediatric population are: Streptococci, Staphylococci and Enterococci. The classical signs of infective endocarditis like Roth spots, Janeway lesions, splinter haemorrhages and Osler's nodes are relatively rare in children. A high index of suspicion in a febrile child with a new murmur, detailed history, meticulous examination, repeated blood cultures, and echocardiography are essential in establishing the diagnosis. Management of infective endocarditis involves a prolonged course of antibiotics, at least for 4–6 weeks depending upon the causative organism and underlying heart condition. Complications of infective endocarditis include congestive heart failure resulting from valvular damage/regurgitation, infective emboli leading to abscesses in other organs and abnormal host immunological responses. Prophylactic antibiotics for dental and other medical procedures like genitourinary tract procedures are no longer recommended in the UK. The emphasis should be on educating children and their parents in early recognition of infective endocarditis. Children at high risk of developing endocarditis should be assessed urgently after clinical suspicion.     

Late prosthetic valve endocarditis due to Cardiobacterium hominis, an unusual complication

We report a case of prosthetic valve endocarditis caused by Cardiobacterium hominis in a patient who had undergone atrial septal defect closure and mitral valve replacement of the heart in 1978. He presented with pyrexia of unknown origin and congestive cardiac failure. Investigations revealed infective endocarditis of prosthetic valve in mitral portion. Blood culture samples grew C. hominis. The patient was empirically started on vancomycin and gentamicin intravenously and ceftriaxone was added after isolation of the organism. Though subsequent blood cultures were negative, patient remained in congestive cardiac failure and died due to complications.     

HACEK endocarditis: state-of-the-art

The HACEK group of bacteria – Haemophilus parainfluenzae, Aggregatibacter spp. (A. actinomycetemcomitans, A. aphrophilus, A. paraphrophilus, and A. segnis), Cardiobacterium spp. (C. hominis, C. valvarum), Eikenella corrodens, and Kingella spp. (K. kingae, K. denitrificans) – are fastidious gram-negative bacteria, part of the normal microbiota of oral and upper respiratory tract in humans. Although their pathogenicity is limited, they are responsible for 1-3% of all infective endocarditis. HACEK endocarditis mostly affect patients with underlying heart disease or prosthetic valves, and are characterized by an insidious course, with a mean diagnosis delay of 1 month (Haemophilus spp.) to 3 months (Aggregatibacter and Cardiobacterium spp.). The advent of continuously monitored blood culture systems with enriched media has erased the need for extended incubation for the diagnosis of HACEK endocarditis. Medical treatment relies on third-generation cephalosporin, with a favorable outcome in 80-90% of cases, with or without cardiac surgery.     

Cardiobacterium valvarum临床分离株的生物学特性研究及16S rRNA鉴定

目的 采用不同的方-法描述Cardiobacterium valvarum(C. valvarum)临床分离株的生物学特性,利用16S rRNA基因测序技术进行分子鉴定。 方-法 转种阳性血培养标本到血琼脂平板上进行细菌培育,革兰染色涂片镜检,用VITEK 2 Compact全自动微生物鉴定分析仪对临床分离株进行细菌鉴定,基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)对分离株的蛋白质进行高通量测定,E-test法对分离株作药敏试验。提取分离株的DNA,采用16S rRNA基因测序技术对PCR的产物进行测序,在NCBI的BLAST网站上与GenBank数据库上的序列做相似性比较,用MEGA7.0.26软件构建该分离株的系统进化树。结果 经细菌培养发现小而圆、光滑、不透明,灰色的菌落;经革兰染色后镜下见到小、两端圆形、革兰阴性的多形性杆菌;VITEK 2 Compact上机、MALDI-TOF-MS技术均未得到该分离株的鉴定结-果;16S rRNA基因测序技术测得该菌株基因全序列约为1 450 bp,与C. valvarum F0432的16S rRNA同源性为99.59%,鉴定为C. valvarum。结论该菌的形态、生化反应均无代表性,采用16S rRNA基因测序技术可以对C. valvarum进行鉴定,对该疾病的诊断具有重要意义。     

人心杆菌败血症1例

患者男,64岁,公务员。因左下腹疼痛伴肛门停止排便、排气1月余,在当地医院住院,腹部X线片显示肠梗阻,后腹痛缓解,予保守治疗后大便通畅,但出现左腰部疼痛。CT检查发现左输尿管中段狭窄合并左肾积水,行左输尿管镜检查并插双J管引流。2周后复查,肾积水减轻,遂于膀胱镜下拔除双J管。拔管后患者出现寒战、高热,体温高达39．9℃,无其他不适。予右美沙芬（美林）治疗后,体温降至正常,但过后仍持续发热。     

Late aortic homograft valve endocarditis caused by Cardiobacterium hominis: a case report and review of the literature

An unusual case of Cardiobacterium hominis endocarditis involving an aortic homograft valve is presented. Although the patient was young (a 17 year old man) and showed few of the characteristic features of the disease, the report does illustrate a number of the problems associated with this illness and highlights the need for the careful assessment of apparent culture negative endocarditis. The organism itself is susceptible to most antibiotics but further treatment, including surgery, may be necessary. Patients must therefore be examined repeatedly and assessed for haemodynamic deterioration, valve destruction or embolic phenomena. Homograft valve replacement may offer some benefits in the setting of aortic valve endocarditis and is therefore an attractive option in this situation.


Keywords: Cardiobacterium hominis; endocarditis; valve replacement     

Cardiobacterium hominis endocarditis presenting as acute embolic stroke: A case report and review of the literature

We report on a case of endocarditis attributable to Cardiobacterium hominis in a 31-year-old man who presented with acute-onset, left-sided hemiparesthesia. Magnetic resonance imaging of the brain showed acute infarctions in 2 areas of the right cerebral cortex, and a transesophageal echocardiogram revealed vegetation in a previously unrecognized bicuspid aortic valve. The patient completed a 6-week course of ceftriaxone and aspirin, with resolution of the vegetation and neurological complications. Our literature review of C. hominis endocarditis suggests that aortic-valve involvement is associated with high stroke and valve-surgery rates. Favorable outcomes and treatment success are evident with either penicillin or ceftriaxone, in combination with (if indicated) valve surgery in patients with neurological complications.     

Prosthetic valve endocarditis

Prosthetic valve endocarditis is a catastrophic complication of cardiac valve replacement, associated with high mortality rates. Medical treatment is effective in a few instances of endocarditis involving the leaflets alone in bioprostheses. However, accurate diagnosis, better myocardial protection, and improved surgical strategies have led to better survival in patients undergoing surgery after failed conservative therapy. This comprehensive review addresses various issues involved in the management of this complication.     

Subacute bacterial endocarditis caused by Cardiobacterium hominis: A case report

Cardiobacterium hominis, a member of the HACEK group of organisms, is an uncommon but important cause of subacute bacterial endocarditis. First-line therapy is a third-generation cephalosporin due to rare beta-lactamase production. The authors report a case involving endovascular infection due to C hominis that initially tested resistant to third-generation cephalosporins using an antibiotic gradient strip susceptibility method (nitrocephin negative), but later proved to be susceptible using broth microdilution reference methods (a ‘major’ error). There are limited studies to guide susceptibility testing and interpretive breakpoints for C hominis in the medical literature, and the present case illustrates some of the issues that may arise when performing susceptibility testing for fastidious organisms in the clinical microbiology laboratory.