Cardiobacterium hominis endocarditis complicated by aortic root abscess: a case report.
ABSTRACT: The present report describes a case of infective endocarditis complicated with aortic root abscess caused by Cardiobacterium hominis in a 56-year-old man. C. hominis is a microaerophilic, pleomorphic Gram-negative bacillus and member of the Haemophilus species, Aggregatibacter actinomycetemcomitans , C. hominis , Eikenella corrodens and Kingella kingae (HACEK) group, a group of bacteria known to be a rare cause of endocarditis. With prompt diagnosis and initiation of antimicrobial and surgical management, a successful outcome was achieved.
Project description:To elucidate the putative function of a gene, effective tools are required for genetic characterization that facilitate its inactivation, deletion or modification on the bacterial chromosome. In the present study, the nucleotide sequence of the Escherichia coli/Aggregatibacter actinomycetemcomitans shuttle vector pYGK was determined, allowing us to redesign and construct a new shuttle cloning vector, pJT4, and promoterless lacZ transcriptional/translational fusion plasmids, pJT3 and pJT5. Plasmids pJT4 and pJT5 contain the origin of replication necessary to maintain shuttle vector replication. In addition, a new suicide vector, pJT1, was constructed for the generation of scarless and markerless deletion mutations of genes in the oral pathogen A. actinomycetemcomitans. Plasmid pJT1 is a pUC-based suicide vector that is counter-selectable for sucrose sensitivity. This vector does not leave antibiotic markers or scars on the chromosome after gene deletion and thus provides the option to combine several mutations in the same genetic background. The effectiveness of pJT1 was demonstrated by the construction of A. actinomycetemcomitans isogenic qseB single deletion (?qseB) mutant and lsrRK double deletion mutants (?lsrRK). These new vectors may offer alternatives for genetic studies in A. actinomycetemcomitans and other members of the HACEK (Haemophilus spp., A. actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) group of Gram-negative bacteria.
Project description: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.
Project description:Cardiobacterium hominis is a well-known commensal bacterium of the oral cavity and an agent of infective endocarditis in humans. Here, we provide a draft genome sequence of a pathogenic strain isolated from blood cultures of a patient with infectious endocarditis.
Project description: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.
Project description:A fastidious gram-negative bacterium was isolated from the blood of a 37-year-old man who had insidious endocarditis with a sudden rupture of a cerebral aneurysm. Characterization of the organism through phylogenetic and phenotypic analyses revealed a novel species of Cardiobacterium, for which the name Cardiobacterium valvarum sp. nov. is proposed. C. valvarum will supplement the current sole species Cardiobacterium hominis, a known cause of endocarditis. Surgeries and antibiotic treatment cured the patient's infection and associated complications. During cardiac surgery, a congenital bicuspid aortic valve was found to be the predisposing factor for his endocarditis.
Project description:Bacterial DNA was detected directly in the serum of a patient with endocarditis by broad-range 16S rRNA PCR followed by sequencing and analysis of the results by the BLAST search. Using these methods, Cardiobacterium hominis was identified in 2 days from the date of serum collection. The microorganism was also isolated and identified using conventional methods (bacterial culture and biochemical tests) 17 days from the date of sample collection. This is the first report showing the direct detection of C. hominis in a patient's serum using molecular-based methods, emphasizing their potential usefulness as additional and rapid diagnostic tools for the detection and identification of fastidious bacteria.
Project description:We report a case with infective endocarditis (IE) due to Cardiobacterium valvarum . The patient was a 57-year-old male, who was referred to our hospital based on suspected IE detected by transthoracic echocardiography at a neighbourhood clinic. Three sets of blood cultures obtained on admission yielded positive results, and revealed rather slender and linear Gram-negative bacilli with a rosette formation that dyed minimally, with a pale white appearance. Although no isolates were identified by conventional methods, C. valvarum was ultimately identified by 16 S ribosomal RNA genotyping. HACEK group strains are difficult to identify by conventional methods. Therefore, if Gram-negative bacilli are isolated from IE patients, 16 S ribosomal RNA genotyping will be necessary. Furthermore, IE due to C. valvarum is very rare. We thus discuss our case in comparison with previous reports.
Project description:Against 198 viridans group streptococci, 25 Streptococcus bovis strains, and 5 Cardiobacterium hominis strains, MICs of DX-619, a des-F(6)-quinolone, were between 0.004 and 0.25 microg/ml. These MICs were lower than those of other quinolones (< or = 0.008 to > 32 microg/ml). Beta-lactam MICs were between < or = 0.008 and 16 microg/ml. Azithromycin resistance was found in most species, while most were telithromycin susceptible. Glycopeptides and linezolid were active against viridans group strains but inactive against C. hominis.