Endocarditis due to Aggregatibacter Segnis: a rare case report.

BACKGROUND: As a member of the HACEK group, Aggregatibacter segnis (A. segnis) is a fastidious Gram-negative coccobacillus that resides in the human oropharyngeal flora. Infective endocarditis caused by A. segnis is rarely reported. CASE PRESENTATION: A 31-year-old male was admitted to our hospital for a 3-month history of intermittent high fever, chills, and chest distress. On presentation, he was febrile and tachycardic but otherwise with stable vital signs. Physical examination revealed systolic murmurs in the aortic and mitral valve areas. Pitting edema was evident in the lower extremities. Transthoracic echocardiography demonstrated multiple vegetations in the mitral and aortic valves. Severe regurgitation of the aortic valve and left heart dysfunction were also detected. With the suspicion of infective endocarditis and heart failure, we immediately performed microbiological tests and arranged the cardiac replacement surgery. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and metagenomic next-generation sequencing (mNGS) identified A. segnis from the bloodstream. While the surgical specimen culture was negative, the mNGS was positive for A. segnis. The patient was treated with ceftriaxone for four weeks and discharged. He remained clinically well, with laboratory results restored. CONCLUSION: This is the first report of A. segnis infective endocarditis that combined MALDI-TOF and metagenomic next-generation sequencing in the diagnosis. The hypothesis-independent molecular techniques can outperform conventional tools to prevent diagnostic delay.

[Aggregatibacter segnis endocarditis mimicking antineutrophil cytoplasmic antibody-associated vasculitis presenting with cerebral hemorrhage: a case report].

A 56-year-old man who underwent a tooth extraction in the previous year presented with weakness of the right upper extremity. Brain CT and MRI scans showed subcortical hemorrhage in the left frontal lobe. His body temperature was 37.5°C. Blood examination revealed anemia, elevated levels of C-reactive protein, and a positive result for PR3-ANCA. Aggregatibacter segnis was identified in the incubated blood cultures, and transesophageal echocardiograms showed infectious growth in the anterior mitral leaflet. He was diagnosed with infectious endocarditis. After treatment with ceftriaxione, the clinical symptoms were improved. We concluded that infectious endocarditis caused cerebral hemorrhage and that the positive result for PR3-ANCA was a false positive. Infectious endocarditis can mimic ANCA-associated vasculitis. When ANCA-associated vasculitis is suspected, infectious endocarditis must be ruled out.

Periodontal disease bacteria specific to tonsil in IgA nephropathy patients predicts the remission by the treatment.

BACKGROUND: Immunoglobulin (Ig)A nephropathy (IgAN) is the most common form of primary glomerulonephritis in the world. Some bacteria were reported to be the candidate of the antigen or the pathogenesis of IgAN, but systematic analysis of bacterial flora in tonsil with IgAN has not been reported. Moreover, these bacteria specific to IgAN might be candidate for the indicator which can predict the remission of IgAN treated by the combination of tonsillectomy and steroid pulse. METHODS AND FINDINGS: We made a comprehensive analysis of tonsil flora in 68 IgAN patients and 28 control patients using Denaturing gradient gel electrophoresis methods. We also analyzed the relationship between several bacteria specific to the IgAN and the prognosis of the IgAN. Treponema sp. were identified in 24% IgAN patients, while in 7% control patients (P = 0.062). Haemophilus segnis were detected in 53% IgAN patients, while in 25% control patients (P = 0.012). Campylobacter rectus were identified in 49% IgAN patients, while in 14% control patients (P = 0.002). Multiple Cox proportional-hazards model revealed that Treponema sp. or Campylobactor rectus are significant for the remission of proteinuria (Hazard ratio 2.35, p = 0.019). There was significant difference in remission rates between IgAN patients with Treponema sp. and those without the bacterium (p = 0.046), and in remission rates between IgAN patients with Campylobacter rectus and those without the bacterium (p = 0.037) by Kaplan-Meier analysis. Those bacteria are well known to be related with the periodontal disease. Periodontal bacteria has known to cause immune reaction and many diseases, and also might cause IgA nephropathy. CONCLUSION: This insight into IgAN might be useful for diagnosis of the IgAN patients and the decision of treatment of IgAN.

The antibacterial activity of various saturated and unsaturated fatty acids against several oral pathogens.

The antibacterial activity of various saturated fatty acids (SFA) and unsaturated fatty acids (USFA) against different oral pathogens which are implicated in the cause of dental caries, stomatitis, gingivitis, and periodontitis was examined. The saturated fatty acids Pa, StA and ArA, and the unsaturated omega-7 fatty acids PLA and omega-9 fatty acids OA showed either none to low antimicrobial activity against all of the 12 oral pathogenic strains used in this study. In contrast, the omega-3 PUFAs, ALA, SDA, EPA and DHA, and the omega-6 PUFAs, LA, GLA, and AA showed considerable antimicrobial activity against 8, 7, 6 and 5 strains, and 6, 10 and 5 strains, respectively. In particular, the omega-3 and omega-6 PUFAs showed strong antimicrobial activity against Porphyromonas gingivalis KCTC 381, the cause of periodontitis, and against Aggregatibacter segnis KCTC 5968, Fusobacterium nucleatum subsp. Polymorphum KCTC 5172 and Prevotella intermedia KCTC 25611, all organisms implicated in the cause of gingivitis. To date, no bacterial resistance to free fatty acids has been encountered and no resistance phenotype has emerged. Therefore, these results suggest that PUFAs may be useful in the development of therapeutic agents for oral diseases, and in particular, in the development of agents that have minimal side effects and against which there is no bacterial resistance.