Cardiobacterium hominis endocarditis: Two cases and a review of the literature

Association Between Healthy Eating Index-2020 and Oral Microbiome Among Postmenopausal Women

BACKGROUND

Dietary intake has been suggested to be associated with the oral microbiome, but no study has examined the association between overall diet quality and the oral microbiome.

OBJECTIVES

This study aimed to investigate the cross-sectional association between the Healthy Eating Index-2020 (HEI-2020) and the diversity and composition of the oral microbiome among participants in the Buffalo Osteoporosis and Periodontal Disease (OsteoPerio) Study.

METHODS

In 1175 postmenopausal women (mean age: 67 ± 7.0 y), we estimated the HEI-2020 scores for each woman from a food frequency questionnaire administered from 1997 to 2000. Bacterial DNA was extracted from subgingival plaque samples and analyzed using 16S ribosomal RNA sequencing. The alpha-diversity (within-sample diversity) and β-diversity (between-sample diversity) across HEI-2020 quartiles were examined using analysis of covariance and permutational multivariate analysis of variance, respectively. The associations between the HEI-2020 score and the relative abundance of microbial taxa were examined by linear regression models. The analyses were further conducted for individual components of the HEI-2020.

RESULTS

No statistically significant associations were observed between the HEI-2020 scores and alpha- or beta-diversity. However, greater consumption of seafood, plant proteins, and total protein and lower consumption of added sugars were positively associated with alpha-diversity. After we applied a false detection rate (FDR) correction, higher HEI-2020 scores were significantly associated with decreased abundance of Lautropia, Streptococcus gordonii, Cardiobacterium valvarum, and Cardiobacterium hominis, and increased abundance of Selenomonas sp. oral taxon 133 and Selenomonas dianae (FDR-adjusted P values < 0.10). Additionally, 28 other taxa were identified as being associated with HEI-2020 components.

CONCLUSIONS

Although the HEI-2020 was associated with the composition, but not the diversity, of the oral microbiome, individual HEI-2020 components were associated with both its diversity and composition. Specific dietary components may have more impact on the diversity and composition of oral microbiome than overall diet quality assessed by the HEI-2020.

Plaque Microbiome in Caries-Active and Caries-Free Teeth by Dentition

OBJECTIVE

Describe associations between dental caries and dental plaque microbiome, by dentition and family membership.

METHODS

This cross-sectional analysis included 584 participants in the Center for Oral Health Research in Appalachia Cohort 1 (COHRA1). We sequenced the 16S ribosomal RNA gene (V4 region) of frozen supragingival plaque, collected 10 y prior, from 185 caries-active (enamel and dentinal) and 565 caries-free (no lesions) teeth using the Illumina MiSeq platform. Sequences were filtered using the R DADA2 package and assigned taxonomy using the Human Oral Microbiome Database.

RESULTS

Microbiomes of caries-active and caries-free teeth were most similar in primary dentition and least similar in permanent dentition, but caries-active teeth were significantly less diverse than caries-free teeth in all dentition types. Streptococcus mutans had greater relative abundance in caries-active than caries-free teeth in all dentition types (P < 0.01), as did Veillonella dispar in primary and mixed dentition (P < 0.01). Fusobacterium sp. HMT 203 had significantly higher relative abundance in caries-free than caries-active teeth in all dentition types (P < 0.01). In a linear mixed model adjusted for confounders, the relative abundance of S. mutans was significantly greater in plaque from caries-active than caries-free teeth (P < 0.001), and the relative abundance of Fusobacterium sp. HMT 203 was significantly lower in plaque from caries-active than caries-free teeth (P < 0.001). Adding an effect for family improved model fit for Fusobacterium sp. HMT 203 but notS. mutans.

CONCLUSIONS

The diversity of supragingival plaque composition from caries-active and caries-free teeth changed with dentition, but S. mutans was positively and Fusobacterium sp. HMT 203 was negatively associated with caries regardless of dentition. There was a strong effect of family on the associations of Fusobacterium sp. HMT 203 with the caries-free state, but this was not true for S. mutans and the caries-active state.

KNOWLEDGE TRANSFER STATEMENT

Patients' and dentists' concerns about transmission of bacteria within families causing caries should be tempered by the evidence that some shared bacteria may contribute to good oral health.

Ceftriaxone-induced neutropenia successfully overcome by a switch to penicillin G in Cardiobacterium hominis endocarditis

Leukopenia, including agranulocytosis, is a severe complication of treatment with all β-lactam antibiotics. Its incidence increases with age. Cardiobacterium hominis endocarditis after implantation of an aortic valve bio-prosthesis in a 77-year-old woman was treated with ceftriaxone 2 g/day plus gentamicin 160 mg/day intravenously. On Day 25 of treatment, blood leukocytes had decreased to 1800/μl (neutrophils 370/μl). Antibiotic therapy was switched to penicillin G 20 million international units (IU)/day. Thereafter, blood leukocytes including neutrophils normalized suggesting that penicillin G was less bone marrow-toxic than ceftriaxone. High-dose ciprofloxacin, the alternative to penicillin G, was avoided because of the risk of cognitive and behavioral side effects. The present case suggests that with close laboratory monitoring a β-lactam with differing side chains should not be considered contraindicated after β-lactam antibiotic-induced neutropenia.

Infective endocarditis after transcatheter pulmonary valve implantation in patients with congenital heart disease: Distinctive features

The introduction of transcatheter pulmonary valve implantation (TPVI) has greatly benefited the management of right ventricular outflow tract dysfunction. Infective endocarditis (IE) is a feared complication of TPVI that affects valve durability and patient outcomes. Current recommendations provide only limited guidance on the management of IE after TPVI (TPVI-IE). This article, by a group of experts in congenital heart disease in children and adults, interventional cardiology, infectious diseases including IE, and microbiology, provides a comprehensive review of the current evidence on TPVI-IE, including its incidence, risk factors, causative organisms, diagnosis, and treatment. The incidence of TPVI-IE varies from 13-91/1000 person-years for Melody valves to 8-17/1000 person-years for SAPIEN valves. Risk factors include history of IE, DiGeorge syndrome, immunosuppression, male sex, high residual transpulmonary gradient and portal of bacteria entry. Staphylococci and streptococci are the most common culprits, whereas Staphylococcus aureus is associated with the most severe disease. In addition to the modified Duke criteria, a high residual gradient warrants a strong suspicion. Imaging studies are helpful for the diagnosis. Intravenous antibiotics guided by blood culture results are the mainstay of treatment. Invasive re-intervention may be required. TPVI-IE in patients with congenital heart disease exhibits several distinctive features. Whether specific valve types are associated with a higher risk of TPVI-IE requires further investigation. Patient and parent education regarding IE prevention may have a role to play and should be offered to all patients.

Cardiobacterium hominis infective endocarditis: A literature review

Background

Cardiobacterium hominis is a member of the HACEK group, which causes infective endocarditis (IE) but is rarely associated with other infections. It is difficult to biologically identify C. hominis because of its slow growth in culture. However, the clinical features of C. hominis IE remain unclear.

Method

We searched the PubMed database for all articles of C. hominis IE published between January 2000 and July 2022.

Results

The major clinical features of 44 previously reported cases of C. hominis IE were as follows: the median age was 59 years, of which 36 were men; the initial presenting symptoms were chest discomfort (30 %), followed by fever (27 %), night sweats (20 %), fatigability (18 %), weight loss (16 %), and dyspnea (16 %). Almost half of the patients were febrile upon admission. The major predisposing factors were postsurgical valve treatment (57 %), dental treatment or caries (20 %), and congenital valve abnormality (5 %). The median time to identify C. hominis in the blood culture was 4 days, but the longest time was 42 days. The most commonly infected valve was the aortic valve, and the most common complication was systemic embolism. Surgical treatment was performed in 23 (52 %) patients. The most frequent initial treatment regimen was cephem antibiotics, with a median treatment duration of 6 weeks. The overall mortality and recovery rates of C. hominis IE were 9 % and 91 %, respectively.

Conclusion

If C. hominis infection is confirmed, physicians should check for the presence of vegetations of the heart valves and understand these characteristics.

Metaproteomic Analysis of an Oral Squamous Cell Carcinoma Dataset Suggests Diagnostic Potential of the Mycobiome

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy, with an estimated 5-year survival rate of only 40-50%, largely due to late detection and diagnosis. Emerging evidence suggests that the human microbiome may be implicated in OSCC, with oral microbiome studies putatively identifying relevant bacterial species. As the impact of other microbial organisms, such as fungi and viruses, has largely been neglected, a bioinformatic approach utilizing the Trans-Proteomic Pipeline (TPP) and the R statistical programming language was implemented here to investigate not only bacteria, but also viruses and fungi in the context of a publicly available, OSCC, mass spectrometry (MS) dataset. Overall viral, bacterial, and fungal composition was inferred in control and OSCC patient tissue from protein data, with a range of proteins observed to be differentially enriched between healthy and OSCC conditions, of which the fungal protein profile presented as the best potential discriminator of OSCC within the analysed dataset. While the current project sheds new light on the fungal and viral spheres of the oral microbiome in cancer in silico, further research will be required to validate these findings in an experimental setting.

Bacterial endocarditis with AACEK (HACEK) organisms

INTRODUCTION

Gram-negative organisms of the AACEK group, formerly known as HACEK, rarely cause endocarditis.

CASE SERIES

We present three cases of bacterial endocarditis, involving native and prosthetic valves, caused by AACEK organisms. In two patients, Cardiobacterium hominis was the responsible organism, and in a third, Aggregatibacter aphrophilus was implicated. A dental source of infection was identified in two patients, and in all three patients, the presentation of endocarditis was subacute.

DISCUSSION

This case series highlights the indolent nature of infection with the AACEK organisms. It also demonstrates the crucial role of multimodality imaging, especially transesophageal echocardiography, in the diagnosis of AACEk endocarditis of both native and prosthetic valves, and in delineating the extent of abscess in those with prosthetic valve infection.

Apyretic pulmonary oedema revealing Cardiobacterium hominis endocarditis: case report and review of literature

Cardiobacterium hominis is a member of the HACEK group of bacteria, responsible for infective endocarditis, mainly in patients with damaged or prosthetic valves. The low virulence of this organism can explain the insidious presentation and subacute or chronic progression of C. hominis infective endocarditis. Here, a 41-year-old man with a past history of surgery for a Waldhausen type aortic coarctation was hospitalised with dyspnea and chest pains revealing an acute pulmonary oedema, without fever. Transesophageal echocardiography indicated a 20 mm vegetation on biscuspid aortic valve. Six sets of blood culture were positive with Cardiobacterium hominis. In case of lack of fever, the diagnosis of infectious endocarditis is difficult because other symptoms are non-specific and biological markers of inflammatory syndrome are quiet or non-existent. This is the first case of C. hominis infectious endocarditis with a clinical presentation of acute pulmonary oedema in the literature. We report here an apyretic pulmonary oedema revealing C. hominis endocarditis and a review of the literature on apyretic infective endocarditis due to C. hominis.

Staphylococcus lugdunensis Infectious Endocarditis Complicated by Embolic Stroke After Colonoscopy in a 58-Year-Old Female

There are a significant number of colonoscopies and esophagogastroduodenoscopies (EGDs) done in the United States every year and post-endoscopic infections are frequently seen. Data demonstrating causality between endoscopic procedures and infectious endocarditis (IE) or that antibiotic prophylaxis prior to endoscopic procedures protects against IE is still lacking. Here we have presented the case of a patient who underwent diagnostic colonoscopy as part of a malignancy workup and was later found to be septic with Staphylococcus lugdunensis bacteremia and had IE. We hypothesized that the infection was most likely contracted during colonoscopy as a result of bacterial translocation from the perineal region to the bloodstream. This case report highlights the need for further studies investigating the efficacy of prophylactic antibiotics in reducing the risk of IE after colonoscopies.

Cardiobacterium hominis endocarditis incidentally diagnosed following an aortic valve replacement surgery

Background

Cardiobacterum hominis (C. hominis) is the part of the HACEK group (Haemophilus spp, Actinobacillus spp, C. hominis, Eikenella, and Kingella spp) that accounts for the majority of the Gram-negative infective endocarditis cases. Historically, the fastidious characteristics of these microorganisms proved challenging to many clinicians. Advances in microbiological identification of culture-negative endocarditis; however, may be the reason for the rising incidence of these infections. Here, we report an incidentally diagnosed C. hominis endocarditis following an aortic valve replacement.

Case report

A healthy 54-year-old gentleman presented after several months of generalized weakness and exertional intolerance. He was found to have a bicuspid aortic valve with regurgitation and underwent aortic valve replacement surgery. Intraoperatively, the patient was found to have a large perforation of the fused leaflet associated with abnormal pink tissue in the aortic valve area. The aortic valve tissue was cultured. Gram-negative rods were isolated 48 h later and were ultimately identified as C. hominis. He was successfully treated with 6 weeks of intravenous ceftriaxone with sterile blood cultures throughout the hospital stay. In retrospect, the patient’s valve failure was likely secondary to subacute endocarditis from C. hominis complicated by leaflet perforation.

Conclusion

C. hominis is a rare cause of infective endocarditis with an excellent prognosis when timely diagnosed and managed. By reporting this case, we wish to raise awareness of potential asymptomatic infection, particularly amongst patients with underlying native valve abnormalities, new leaflet perforation, and valve insufficiency.

Hemolytic Anemia in a Patient with Subacute Bacterial Endocarditis by Cardiobacterium hominis

Hemolytic anemia is a rarely occurring manifestation of native valve infective endocarditis. We herein report an afebrile patient with hemolytic anemia caused by Cardiobacterium hominis endocarditis. A 60-year-old Japanese man had a history of aortic root replacement and the gradual onset of general fatigue. He had hemolytic anemia. Blood cultures detected C. hominis. A transthoracic echocardiogram showed aortic valve vegetation and periannular abscess with perforation of the non-coronary cusp. Intravascular hemolysis recovered after antimicrobial therapy, surgical removal of the vegetation and abscess, and aortic valve replacement. Subacute endocarditis should be considered if patients develop hemolytic anemia with signs of chronic inflammation without a fever.

An unexpected case of Cardiobacterium valvarum prosthetic arthritis without cardiac lesions: Case report and literature review

We report a case of prosthetic arthritis caused by Cardiobacterium valvarum, which has been exclusively reported to cause intravascular infections. A 81-year-old Japanese female complained prosthetic knee joint pain. Arthrocentesis cultured no pathogen, and surgical replacement of the implant surface was performed. Modified Levinthal medium culture and 16S rRNA sequencing has finally led to diagnosis of C. valvarum prosthetic knee arthritis without cardiac lesions. Fastidious bacteria such as C. valvarum can be candidate pathogens of orthopedic infections whose causative agents are sometimes unidentified. Further development of molecular diagnostics is expected, but also the importance of conventional methods should be noted.

Aneurysm of the anterior tibial artery as a complication of infectious endocarditis

OBJECTIVE

Mycotic aneurysms of the infrapopliteal vessels are rare, with few cases reported in the literature. Management strategies are diverse and should be tailored to the patient's presentation.

METHODS

We describe the case of a 40-year-old male who presented with a painful left leg mass in the setting of bacteremia and infective endocarditis. Imaging revealed an aneurysm of the anterior tibial artery.

RESULTS

The patient was treated with antibiotics and open surgical repair with excision of the aneurysmal sac, ligation of the anterior tibial artery, and primary repair of the popliteal artery and tibioperoneal trunk.

CONCLUSION

The epidemiology, pathophysiology, and clinical management of infrapopliteal aneurysms are briefly reviewed in this case study.

Oral microbiome and onset of oral mucositis in patients with squamous cell carcinoma of the head and neck

BACKGROUND

Oral mucositis (OM) is a debilitating sequela for patients treated for squamous cell carcinoma of the head and neck (HNSCC). This study investigated whether oral microbial features before treatment or during treatment are associated with the time to onset of severe OM in patients with HNSCC.

METHODS

This was a cohort study of newly diagnosed patients with locoregional HNSCC who received chemotherapy with or without radiotherapy from April 2016 to September 2017. OM was based on the National Cancer Institute's Common Terminology Criteria for Adverse Events, version 4.0. The oral microbiome was characterized on the basis of the 16S ribosomal RNA V4 region with the Illumina platform. A mixture cure model was used to generate hazard ratios for the onset of severe OM.

RESULTS

Eighty-six percent of the patients developed OM (n = 57 [33 nonsevere cases and 24 severe cases]) with a median time to onset of OM of 21 days. With adjustments for age, sex, and smoking status, genera abundance was associated with the hazard for the onset of severe OM as follows: 1) at the baseline (n = 66), Cardiobacterium (P = .03) and Granulicatella (P = .04); 2) immediately before the development of OM (n = 57), Prevotella (P = .03), Fusobacterium (P = .03), and Streptococcus (P = .01); and 3) immediately before the development of severe OM (n = 24), Megasphaera (P = .0001) and Cardiobacterium (P = .03). There were no differences in α-diversity between the baseline samples and Human Microbiome Project data.

CONCLUSIONS

Changes in the abundance of genera over the course of treatment were associated with the onset of severe OM. The mechanism and therapeutic implications of these findings need to be investigated in future studies.

A Case Report of Cardiobacterium hominis Endocarditis in a Pregnant Woman

Infective endocarditis (IE) is an infrequent endovascular disease, which can result in significant mortality and morbidity. Staphylococcus aureus and viridans streptococci remain the most common etiological agent. Cardiobacterium hominis, a member of the HACEK (Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species) group of fastidious gram-negative bacillus, is a part of normal upper respiratory flora and a rare cause implicated in IE. Cases of Cardiobacterium hominis endocarditis are being increasingly reported in last few years due to advancement in automated blood culture system such as BacT/ALERT Virtuo^® and identification system such as MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry). We herein report a first case of Cardiobacterium hominis endocarditis in a pregnant woman at 20 weeks of gestation. Following spontaneous abortion and evacuation of the fetus, appropriate surgical intervention under heparinized condition and pathogen-directed medical intervention was initiated in this patient. This case report highlights the importance of appropriate antimicrobial therapy, which augments earlier resolution of the disease.

Obstructive heart failure with Cardiobacterium hominis infective endocarditis

We illustrate the progression of Cardiobacterium hominis infective endocarditis in a patient with a bioprosthetic mitral valve and decompensated heart failure secondary to an obstructive septic vegetation.

Characteristics of the urinary microbiome in kidney stone patients with hypertension

Background

Kidney stone disease (KSD) is more common in individuals with hypertension (HTN) than in individuals with normotension (NTN). Urinary dysbiosis is associated with urinary tract disease and systemic diseases. However, the role of the urinary microbiome in KSD complicated with HTN remains unclear.

Methods

This study investigated the relationship between the pelvis urinary microbiome and blood pressure (BP) in patients with KSD co-occurring with HTN (KSD-HTN) and healthy controls (HC) by conducting 16S rRNA gene sequencing of bacteria in urine samples. The urine samples were collected (after bladder disinfection) from 50 patients with unilateral kidney calcium stones and NTN (n = 12), prehypertension (pHTN; n = 11), or HTN (n = 27), along with 12 HCs.

Results

Principal coordinates analysis showed that there were significant differences in the urinary microbiomes not only between KSD patients and HCs but also between KSD-pHTN or KSD-HTN patients and KSD-NTN patients. Gardnerella dominated in HCs, Staphylococcus dominated in KSD-NTN patients and Sphingomonas dominated in both KSD-pHTN and KSD-HTN patients. The abundance of several genera including Acidovorax, Gardnerella and Lactobacillus was correlated with BP. Adherens junction and nitrogen and nucleotide metabolism pathways, among others, were associated with changes in BP.

Conclusions

The findings suggest that patients with KSD complicated with HTN have a unique urinary microbiome profile and that changes in the microbiome may reflect disease progression and may be useful to monitor response to treatments.

Bacterial Endocarditis Following Deep Enteroscopy: Is Prophylaxis Warranted?

The development of bacterial endocarditis as a result of endoscopic interventions within the gastrointestinal tract is exceedingly rare. Antibiotic prophylaxis for endoscopic procedures is generally not warranted, except for certain high-risk patients. Double-balloon enteroscopy (DBE) is a common endoscopic procedure for evaluation of the small bowel. Bacterial endocarditis secondary to DBE has not been previously described. We describe the first case of enterococcal endocarditis attributed to DBE in a patient with a history of stage 1 primary biliary cholangitis.

Next-Generation Sequencing for the Diagnosis of Challenging Culture-Negative Endocarditis

Diagnosis of culture-negative infective endocarditis usually implies indirect pathogen identification by serologic or molecular techniques. Clinical metagenomics, relying on next-generation sequencing (NGS) is an emerging approach that allows pathogen identification in challenging situations, as evidenced by a clinical case. We sequenced the DNA extracted from the surgically-removed frozen valve tissue from a patient with suspected infective endocarditis with negative blood and valve cultures. Mapping of the sequence reads against reference genomic sequences, a 16S rRNA gene database and clade-specific marker genes suggested an infection caused by Cardiobacterium hominis.

Infective endocarditis without biological inflammatory syndrome: Description of a particular entity

BACKGROUND

Bacterial infective endocarditis (IE) is rarely suspected in patients with a low C-reactive protein (CRP) concentration.

AIMS

To address the incidence, characteristics and outcome of left-sided valvular IE with low CRP concentration.

METHODS

This was a retrospective analysis of cases of IE discharged from our institution between January 2009 and May 2017. The 10% lowest CRP concentration (<20mg/L) was used to define low CRP concentration. Right-sided cardiac device-related IE, non-bacterial IE, sequelar IE and IE previously treated by antibiotics were excluded.

RESULTS

Of the 469 patients, 13 (2.8%; median age 68 [61-76] years) had definite (n=8) or possible (n=5) left-sided valvular IE with CRP<20mg/L (median 9.3 [4.7-14.2] mg/L). The median white blood cell count was 6.3 (5.3-7.5) G/L. The main presentations were heart failure (n=7; 54%) and stroke (n=3; 23%). Transthoracic echocardiography (TTE) showed vegetations (n=5) or isolated valvular regurgitation (n=4). Overall, eight patients (62%) had severe valvular lesions on transoesophageal echocardiography (TOE), and nine patients (69%) underwent cardiac surgery. All patients survived at 1-year follow-up. Bacterial pathogens were documented in eight patients (streptococci, coagulase-negative Staphylococcus, Corynebacteriumjeikeium, HACEK group, Coxiella burnetii, Bartonella henselae) using blood cultures, serology or valve culture and/or polymerase chain reaction analysis.

CONCLUSIONS

Left-sided valvular IE with limited or no biological syndrome is rare, but is often associated with severe valvular and paravalvular lesions. TOE should be performed in presence of unexplained heart failure, new valvular regurgitation or cardioembolic stroke when TTE is insufficient to rule out endocarditis, even in patients with a low CRP concentration.

Infective endocarditis caused by Cardiobacterium hominis endocarditis: A case report and review of the literature

BACKGROUND

While it has been increasing cases of C. hominis endocarditis in the past decades due to advances of diagnostic methods, the epidemiology and clinical manifestations of IE caused by C. hominis is still unknown.

CASE PRESENTATION

A 62-year old man was admitted to our institute with fever, anorexia and general fatigue for the preceding one month. He had a past medical history of both aortic and mitral valves replacement due to cardiac diseases. He was diagnosed as IE caused by C. hominis according to the modified duke criteria. The patient received 2 weeks of combination therapy of intravenous ceftriaxone (CTRX) 2g and gentamycin 180mg daily followed by 4 weeks CTRX 2g daily alone. Oral moxifloxacin 400mg once daily was given for an additional 4 weeks. After the antibiotic therapy was discontinued, disease recurrence was not observed. We reviewed previously reported C. hominis IE cases in 60 publications including ours. Of 73 patients enrolled, 53 were male, the mean age was 52 years. The most common risk factor of IE was past history of cardiac diseases in 44/73 (60%). As for antibiotics initially prescribed, third-generation cephalosporins was most frequently used in 28/69 (41%). While the cure rate was 67/73 (93%), 31/73 patients (43%) received a surgical intervention. Embolic lesions to the central nervous system and vertebrae were seen in 16/72 (22%) and 5/72 (7%).

CONCLUSION

IE caused by C. hominis has a favorable prognosis, showing the cure rate of 93%. Physicians should recognize the possible occurrence of emboli among IE patients.

A case report of Guillain Barré syndrome revealing underlying infective endocarditis due to Cardiobacterium hominis

RATIONALE

Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy presumed to result from an infection-triggered autoimmune reaction.

PATIENT CONCERNS

This paper describes a 53-year-old man admitted to hospital for deterioration of his general condition.

DIAGNOSIS

He developed GBS, confirmed by lumbar puncture and electromyogram, which recovered after intravenous immunoglobulins. A grade 2 aortic regurgitation was detected by transthoracic echocardiography upon diagnosis of GBS, but in the absence of fever, no further investigations were conducted. A few weeks later, the patient presented with fever and infective endocarditis (IE) was diagnosed after the identification of vegetation on the aortic valve with transesophageal echocardiography. The etiologic agent was identified as Cardiobacterium hominis based on 3 positive blood cultures and DNA detection in valvular material.

INTERVENTIONS

IE was cured with a 6-week course of antibiotics and aortic valve replacement.

OUTCOMES

The patient completely recovered from Guillain-Baré syndrome and IE.

LESSONS

This case of GBS associated with C hominis endocarditis, emphasizes the importance of blood cultures and transesophageal echocardiography for the detection of IE and highlights the insidious nature of C hominis endocarditis which is often diagnosed late.

Vertebral Osteomyelitis, Discitis, and Epidural Abscess: A Rare Complication of Cardiobacterium Endocarditis

In this article, we report the case of a 75-year-old man who was presented with new low back pain for 2 weeks. His past history was significant for severe aortic stenosis necessitating bioprosthetic aortic valve placement 4 years ago, hypertension, and coronary artery disease. His physical examination was positive for point tenderness over the lower lumbar spine. He was found to be bacteremic with Cardiobacterium hominis. Magnetic resonance imaging of the spine showed lumbar (L4-L5) epidural abscess and vertebral osteomyelitis, discitis. He underwent a computed tomography–guided needle biopsy of L4-L5. The biopsy culture was also positive for Cardiobacterium hominis. A transesophageal echocardiogram showed small vegetation on the mitral valve with mild regurgitation. He was started on intravenous ceftriaxone 2 g once daily for a planned duration of 6 weeks and was discharged. However, he, unfortunately, expired at an outside facility secondary to an unknown illness 4 weeks into the treatment course.

Ciprofloxacin for the treatment of Cardiobacterium hominis prosthetic valve endocarditis

Prosthetic valve endocarditis due to Cardiobacterium hominis is rare and recommended therapy includes a third generation cephalosporin. We report a case of Cardiobacterium hominis endocarditis post transcatheter aortic valve replacement in a patient with significant beta-lactam antimicrobial sensitivities who was successfully treated with ciprofloxacin monotherapy in conjunction with surgery.

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.

Subacute bacterial endocarditis caused by Cardiobacterium hominis: A case report

Cardiobacterium hominis is a fastidious organism that can rarely cause subacute bacterial endocarditis. This report describes a case involving a 47-year-old man with subacute endocarditis due to C hominis; the isolate was initally found to be resistant to third-generation cephalosporins, but was later found to be susceptible using an alternative method. The authors discuss the likely cause of this error and emphasize the importance of adherence to fully validated methods for the determination of antibiotic susceptibilities.

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.

Back pain, leg swelling and a cardiac arrest: an interesting case of endocarditis

A 66-year-old woman with a history of tissue aortic valve replacement and chronic back pain presented to the emergency department with a suspected right leg deep vein thrombosis. A recent outpatient MRI had revealed discitis. A ventricular fibrillation cardiac arrest occurred in the emergency department. Cardiac output was restored on the fifth defibrillation. A transthoracic echocardiogram showed large aortic valve vegetations. Clinical impression was of infective endocarditis with cardiac arrest secondary to coronary artery embolisation. Peripheral blood cultures grew Cardiobacterium hominis, and appropriate intravenous antibiotic therapy was administered. The infected prosthetic valve was excised. The patient experienced postoperative complete heart block and a right hemisphere cerebrovascular accident, however she is now recovering well. This case describes an unusual case of infective endocarditis secondary to C. hominis, with disc, leg, coronary artery and brain septic embolisation. Infective endocarditis is an important differential diagnosis in multisystem presentations.

Association between HACEK bacteraemia and endocarditis

We retrospectively examined medical records of 87 patients with bacteraemia caused by members of the HACEK group (Haemophilus parainfluenzae, Aggregatibacter actinomycetemcomitans, Aggregatibacter aphrophilus, Aggregatibacter paraphrophilus, Cardiobacterium spp., Eikenella corrodens and Kingella spp.) to determine whether endocarditis was present, as defined by the Duke criteria. The overall positive predictive value (PPV) of HACEK bacteraemia for endocarditis was 60 %. The PPV varied with different HACEK species from 0 % (E. corrodens) to 100 % (A. actinomycetemcomitans).

The first report of survival post Rothia aeria endocarditis

A 61-year-old patient presented with drowsiness, decreased appetite and weight loss. On examination he had several splinter haemorrhages and a tender mass over the right temporal region. Respiratory and abdominal examinations were unremarkable and heart sounds were normal with no clinically audible murmurs. He spiked regular temperatures and consequently had several blood cultures taken. Transthoracic and transoeseophageal echocardiogram showed a 3 cm mitral valve vegetation. MRI confirmed suspicions of septic emboli in the brain. Blood cultures grew Rothia aeria and he was started on benzylpenicillin, rifampicin and gentamicin. After a period of observation he deteriorated clinically and biochemically, surgical intervention therefore ensued with an urgent metallic mitral valve replacement. Nineteen days postsurgery the patient was successfully discharged on outpatient antibiotic therapy and warfarin. In view of complications such as embolisation and cerebral infarction, R aeria endocarditis should be managed aggressively and with a high index of clinical suspicion.

HACEK infective endocarditis: characteristics and outcomes from a large, multi-national cohort

The HACEK organisms (Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species) are rare causes of infective endocarditis (IE). The objective of this study is to describe the clinical characteristics and outcomes of patients with HACEK endocarditis (HE) in a large multi-national cohort. Patients hospitalized with definite or possible infective endocarditis by the International Collaboration on Endocarditis Prospective Cohort Study in 64 hospitals from 28 countries were included and characteristics of HE patients compared with IE due to other pathogens. Of 5591 patients enrolled, 77 (1.4%) had HE. HE was associated with a younger age (47 vs. 61 years; p<0.001), a higher prevalence of immunologic/vascular manifestations (32% vs. 20%; p<0.008) and stroke (25% vs. 17% p = 0.05) but a lower prevalence of congestive heart failure (15% vs. 30%; p = 0.004), death in-hospital (4% vs. 18%; p = 0.001) or after 1 year follow-up (6% vs. 20%; p = 0.01) than IE due to other pathogens (n = 5514). On multivariable analysis, stroke was associated with mitral valve vegetations (OR 3.60; CI 1.34–9.65; p<0.01) and younger age (OR 0.62; CI 0.49–0.90; p<0.01). The overall outcome of HE was excellent with the in-hospital mortality (4%) significantly better than for non-HE (18%; p<0.001). Prosthetic valve endocarditis was more common in HE (35%) than non-HE (24%). The outcome of prosthetic valve and native valve HE was excellent whether treated medically or with surgery. Current treatment is very successful for the management of both native valve prosthetic valve HE but further studies are needed to determine why HE has a predilection for younger people and to cause stroke. The small number of patients and observational design limit inferences on treatment strategies. Self selection of study sites limits epidemiological inferences.

HACEK-induced endocarditis

A 61-year-old patient with diabetes had a bio-prosthetic aortic valve replacement 3 years before admission. He complained of lethargy, night sweats, decreased appetite and erratic blood glucose with no weight loss. He had splinter haemorrhage and a systolic ejection murmur at the aortic area. Chest and abdominal examination revealed no abnormality. The erythrocyte sedimentation rate and C reactive protein were raised. He had several sets of blood cultures and he was started on empirical vancomycin, rifampicin and gentamicin. Transthoracic echocardiography showed vegetation on the base of the anterior mitral leaflet, which was confirmed by a trans-oesophageal echocardiography. Blood culture was positive for Haemophilus aphrophilus, and he was started on ceftriaxone for 6 weeks instead of vancomycin and rifampicin and continued gentamicin for 2 weeks. Follow-up echocardiography showed no evidence of vegetations. The patient recovered completely and he was discharged home.

[A case of cerebral embolism caused by Cardiobacterium hominis endocarditis]

A 45-year-old woman was referred to our hospital by ambulance with left-sided palsy presented at dinner. Diffusion-weighted magnetic resonance imaging (DWI) showed a somewhat high intensity area in the right frontal lobe, and brain magnetic resonance angiography (MRA) revealed right middle cerebral artery (MCA) occlusion in the M1 distal segment. Although intravenous rt-PA treatment was initiated at 2 hours and 10 minutes after onset, recanalization was not achieved. The patient was diagnosed as infectious endocarditis, because highly echogenic vegetation was observed in the non-coronary cusp of the aortic valve; furthermore, Cardiobacterium hominis was incubated in blood culture, although fever was not so high and C-reactive protein (CRP) was not elevated at the time of hospitalization. It was thought that the bacteremia and infectious endocarditis had occurred due to tooth extraction about six months previously. The diagnosis of infectious endocarditis caused by the HACEK group containing C. hominis may become difficult because the fever was not so high and inflammation was not so severe.

Integrating next-generation sequencing and traditional tongue diagnosis to determine tongue coating microbiome

Tongue diagnosis is a unique method in traditional Chinese medicine (TCM). This is the first investigation on the association between traditional tongue diagnosis and the tongue coating microbiome using next-generation sequencing. The study included 19 gastritis patients with a typical white-greasy or yellow-dense tongue coating corresponding to TCM Cold or Hot Syndrome respectively, as well as eight healthy volunteers. An Illumina paired-end, double-barcode 16S rRNA sequencing protocol was designed to profile the tongue-coating microbiome, from which approximately 3.7 million V6 tags for each sample were obtained. We identified 123 and 258 species-level OTUs that were enriched in patients with Cold/Hot Syndromes, respectively, representing "Cold Microbiota" and "Hot Microbiota". We further constructed the tongue microbiota-imbalanced networks associated with Cold/Hot Syndromes. The results reveal an important connection between the tongue-coating microbiome and traditional tongue diagnosis, and illustrate the potential of the tongue-coating microbiome as a novel holistic biomarker for characterizing patient subtypes.

Cardiobacterium hominis prosthetic valve endocarditis: an infrequent infection

A case of prosthetic aortic valve endocarditis due to Cardiobacterium hominis in a 67-year-old woman is described. The diagnosis was confirmed by a positive blood culture and echocardiographic detection of aortic valve vegetations. The patient underwent replacement of the valve with a homograft, and received antibiotics postoperatively. She remained well after 12 months.

Haemophilus aphrophilus associated spleen abscess: an unusual presentation of subacute endocarditis

The HACEK group of bacteria (Haemophilus spp., Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella spp.), is uncommon pathogens of infective endocarditis, but can cause life-threatening events such as heart failure or formation of lethal emboli. Here we report a 58-year-old Asian man with a past history of congenital valvular heart disease who presented with sudden onset of left flank pain followed by fever with chills for 2 weeks. Abdominal computed tomography (CT) indicated a 1.6 cm abscess in the spleen. Culturing indicated the presence of Haemophilus aphrophilus. We diagnosed the patient with subacute endocarditis complicated with spleen abscess. The patient recovered fully after two weeks antibiotic (Ceftriaxone) treatment. Clinicians should give further attention to infective endocarditis caused by bacteria in the HACEK group in patients with metastatic infection such as spleen abscess with suspected valvular heart disease.

Infective endocarditis in a child caused by Cardiobacterium hominis after right ventricular outflow tract reconstruction using an expanded tetrafluoroethylene conduit

Cardiobacterium hominis, a member of the HACEK group of organisms, is a rare cause of endocarditis. We report a case of infective endocarditis caused by C. hominis in a male child who had undergone right ventricular outflow tract (RVOT) reconstruction using an expanded polytetrafluoroethylene conduit for tetralogy of Fallot with pulmonary atresia. Two days before admission, the patient suffered from exertional shortness of breath. Right ventricular hypertension was confirmed and RVOT stenosis was suspected based on the echocardiography findings. A CT scan revealed vegetation above the cusp of the conduit. An emergency operation was performed to avoid a pulmonary embolism due to large friable vegetation. C. hominis was cultured from the blood and the vegetation, prompting a diagnosis of prosthetic valve endocarditis. The patient was discharged after a 6-week course of intravenous ceftriaxone therapy.

Management of Gram-negative and fungal endocarditis

Infective endocarditis is infrequently caused by Gram-negative bacteria or fungi. Gram-negative organisms are responsible for <4% of cases, whilst fungal endocarditis accounts for <1.5% of culture-positive cases worldwide. Endocarditis due to Gram-negative organisms or fungi is a rare but severe disease. It often has a nosocomial origin, is caused by virulent and often resistant organisms and presents a high rate of complications and high mortality. In this article we present the most recent literature data and address the current management of Gram-negative and fungal infective endocarditis. We also discuss the major challenges of antimicrobial treatment and discuss some issues related to surgical decision-making in difficult-to-manage cases. We finally present our centre's experience with Gram-negative infective endocarditis, with a special focus on the demanding issues that the management of these complex and severely ill patients raise.