Phylogenomic analysis of the understudied Neisseriaceae species reveals a poly- and paraphyletic Kingella genus

IMPORTANCE

Understanding the evolutionary relationships between the species in the Neisseriaceae family has been a persistent challenge in bacterial systematics due to high recombination rates in these species. Previous studies of this family have focused on Neisseria meningitidis and N. gonorrhoeae. However, previously understudied Neisseriaceae species are gaining new attention, with Kingella kingae now recognized as a common human pathogen and with Alysiella and Simonsiella being unique in the bacterial world as multicellular organisms. A better understanding of the genomic evolution of the Neisseriaceae can lead to the identification of specific genes and traits that underlie the remarkable diversity of this family.

Clinical Features and Comparison of Kingella and Non-Kingella Endocarditis in Children, Israel

Kingella spp. have emerged as an important cause of invasive pediatric diseases. Data on Kingella infective endocarditis (KIE) in children are scarce. We compared the clinical features of pediatric KIE cases with those of Streptococcus species IE (StIE) and Staphylococcus aureus IE (SaIE). A total of 60 patients were included in the study. Throughout the study period, a rise in incidence of KIE was noted. KIE patients were significantly younger than those with StIE and SaIE, were predominately boys, and had higher temperature at admission, history of oral aphthae before IE diagnosis, and higher lymphocyte count (p<0.05). Pediatric KIE exhibits unique features compared with StIE and SaIE. Therefore, in young healthy children <36 months of age, especially boys, with or without a congenital heart defect, with a recent history of oral aphthae, and experiencing signs and symptoms compatible with endocarditis, Kingella should be suspected as the causative pathogen.

Endocarditis after closure of ventricular septal defect by transcatheter device

Advances in interventional cardiology have enabled the treatment of severe congenital heart defects without the need for surgery. The percutaneous closure of atrial septal defects and, more recently, ventricular septal defects is considered a safe procedure with fewer complications and less morbidity compared with surgery. We report on a 2-year-old child who developed endocarditis after ventricular septal defect closure with an Amplatzer device. The patient recovered after intravenous antibiotics and anticoagulation. To the best of our knowledge, this is the first report of endocarditis associated with ventricular septal defect closure device insertion.

[Prosthetic endocarditis caused by Kingella denitrificans in a patient with diabetes mellitus]

Infective endocarditis caused by Kingella denitrificans occurs rarely. A review of the literature reveals only 6 cases of endocarditis caused by the bacillus. K. denitrificans is normally a commensal of the upper respiratory airways, may exceptionally be responsible for endocarditis. A case of possible prosthetic endocarditis caused by K. denitrificans is presented. A 78-year-old male with Type II diabetes was admitted to the hospital complaining of fever, a sore throat and arthralgia. He underwent replacement surgery of a St. Jude medical prosthesis for aortic stenosis at the age of 75. The only physical findings at admission were a temperature of 38.2 degrees C and murmurs of mild mitral regurgitation. The liver and spleen were not palpable, and there were no skin or eye lesions. Laboratory findings were as follows: white blood cell count 9500/microliters with 77% neutrophils, erythrocyte sedimentation rate 71 mm/h (Westergren), blood urea nitrogen 50.2 mg/dl, serum creatinine 1.7 mg/dl and C-reactive protein 22.2 mg/dl. The Gram-negative bacillus isolated from the blood was identified as K. denitrificans by the identification system, namely ID test.FN-20 rapid (Nissui, Japan). Although an echocardiogram detected no vegetation, infective endocarditis was diagnosed because the same bacillus was detected by separate blood cultures and an obvious source of infection was not found other than the prosthetic valve. Initial treatment was flomoxef, which was changed to Ampicillin 2 g/day after K. denitrificans was identified. Ampicillin continued for 6 weeks. The clinical course was good and he did not require further surgery. He has been afebrile for 2 years after completing treatment. This case represents the first report of prosthetic valve endocarditis caused by K. denitrificans in Japan.