[Brain abscess due to Aggregatibacter aphrophilus]. / Absceso cerebral por Aggregatibacter aphrophilus.

Brain abscess is a focal suppurative process produced in most cases by bacterial agents. Aggregatibacter aphrophilus is a gram-negative bacteria belonging to the HACEK group, which causes infective endocarditis, liver abscesses, among others. Brain abscesses secondary to this germ are rare and, in most cases, it is associated with contact with pets, poor dental hygiene or dental procedures. Treatment consists of drainage of the abscess (greater than 2.5 cm) combined with antibiotic therapy, ideally beta-lactams. The case of a 64-year-old male patient with no relevant history is here presented. He was admitted to the emergency service due to headache, hemianopsia of a week's duration and later tonic-clonic seizures, in whom imaging studies and culture of a brain lesion subsequently revealed a brain abscess due to A. aphrophilus. This case aims to illustrate about the rarity of this infection, because A. aphrophilus is a normal part of the oropharyngeal flora and respiratory tract, in which it rarely causes invasive bacteremia.

El absceso cerebral es un proceso supurativo focal producido en la mayoría de los casos por agentes bacterianos. Aggregatibacter aphrophilus es una bacteria gram negativa perteneciente al grupo HACEK, causante de endocarditis infecciosa, abscesos hepáticos, entre otras. Los abscesos cerebrales secundarios a este germen son infrecuentes y en la mayoría de los casos asociados a contactos con animales domésticos, pobre higiene dental o procedimientos odontológicos. El tratamiento consiste en drenaje del absceso (mayores de 2.5 cm) combinado con terapia antibiótica, idealmente betalactámicos. Se presenta el caso de un paciente varón de 64 años sin antecedentes de relevancia quien ingresó al servicio de emergencias por cuadro de cefalea, hemianopsias de una semana de evolución y posteriormente crisis tónico clónicas, en quien posteriormente en estudios imagenológicos y cultivo de lesión cerebral se arribó al diagnóstico de absceso cerebral por A. aphrophilus. Este informe tiene como objetivo ilustrar al lector sobre la rareza de esta infección, debido a que A. aphrophilus forma parte normal de la flora orofaríngea y del tracto respiratorio, en los que rara vez ocasiona bacteriemias invasivas.

Aggregatibacter aphrophilus and Eikenella corrodens: a case of brain abscess.

We report a case of a 26-year-old female who developed a brain abscess that was strongly suspected to be caused by Staphylococcus epidermidis, A. aphrophilus, and E. corrodens species. In general, A. aphrophilus and E. corrodens, members of the HACEK group (Haemophilus spp., Aggregatibacter spp., C. hominis, E. corrodens, and K. kingae), have been associated with the development of endocarditis, meningitis, sinusitis, otitis media, pneumonia, osteomyelitis, peritonitis, and wound infections. Cerebral abscesses are a rare manifestation of these bacteria; only a few cases are described in the literature, generally related to the diffusion of these organisms through the bloodstream after a dental procedure or a heart disease. Our case is unique because the rarity of the infection site appeared apparently in absence of risk factors. The patient underwent surgery to drain the abscess and was subsequently put on intravenous antibiotic treatment with ceftriaxone, vancomycin, and metronidazole. After 6 months, brain imaging revealed that the lesion had disappeared. The patient achieved excellent results with this approach.

Brain abscess due to Aggregatibacter aphrophilus in association with atrial septal defect：Case report and literature review.

BACKGROUND: Aggregatibacter aphrophilus（A. aphrophilus）is one of the organisms of the HACEK group. Previously reported cases of brain abscesses caused by A. aphrophilus infection have occurred in children with a basis for congenital heart disease, or in adults with a basis for dental disease. Rare cases of brain abscess caused by A. aphrophilus have been reported in adults with congenital heart disease or in patients without dental disease history. Herein we present a rare case of brain abscess caused by A. aphrophilus, who was in association with atrial septal defect for more than 20 years, and had no dental disease and did not develop infective endocarditis. CASE PRESENTATION: A 51-year-old female was admitted due to progressively worsening headache and left limb weakness for more than 10 days. She denied the history of chronic diseases such as hypertension and diabetes, and no periodontal disease. While she had a history of atrial septal defect, a form of congenital heart disease with severe pulmonary hypertension for more than 20 years. After admission, echocardiographic illustrated congenital heart disease with severe pulmonary hypertension. CT and MRI showed brain abscess. Cerebrospinal fluid (CSF) results also confirmed the presence of intracranial infection. Empirical therapy with vancomycin 1.0 g i.v q12h and meropenem 2.0 g i.v q8h was initiated from the day of admission. On the fourth day after admission, brain abscess resection and decompressive craniectomy were performed, and the pus drained on operation were cultured and Gram-negative bacilli grew, which was identified as A.aphrophilus. Vancomycin was discontinued and meropenem was continued（2.0 g i.v q8h）for 5 weeks, followed by oral levofloxacin 0.5 qd for 4 weeks of out-patient antibiotics. The patient recovered fully within 9 weeks of treatment. CONCLUSIONS: This is the first case of A. aphrophilus to cause brain abscess in adult with a history of congenital heart disease for more than 20 years, who had no dental disease and did not develop infective endocarditis. We also highlight the value of bacterial 16 S rDNA PCR amplification and sequencing in identifying bacteria in abscesses which are culture-negative, and prompt surgical treatment，choosing effective antibiotics and appropriate course of treatment will get better clinical effect.

The first case of cholecytitis caused by Aggregatibacter kilianii in Korea.

BACKGROUND: The bacterial genus Aggregatibacter was categorized in 2006 to accommodate the former Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and H. segnis species. Aggregatibacter kilianii is a normal resident of the human upper respiratory tract but can also cause serious infections. A. kilianii is relatively newly identified and has been isolated from conjunctivitis, wounds, abdominal abscesses, and blood. CASE PRESENTATION: An 80-year-old female patient with distal common bile duct cancer was admitted to our hospital with sudden loss of consciousness and general weakness, fever, and abdominal pain for 3 days. Two colonial morphologies were isolated from both the blood and bile cultures; one was identified as Streptococcus constellatus subsp. pharyngis, but the other was not recognized by Vitek2 and MALDI-TOF. The 16 S rRNA sequences showed 99.73% similarity with the sequence of A. kilianii strains. CONCLUSION AND DISCUSSION: This article presents the first case of a clinical isolate of A. kilianii outside Europe. This case is also the first of the antimicrobial profile of this strain. This report highlights the importance of proper molecular identification for timely diagnosis and treatment of disease.

A rare case of voluminous brain abscess due to Actinomyces meyeri and Aggregatibacter aphrophilus: is there any evidence for a prolonged antibiotic oral relay?

We present the case of a patient with a voluminous cerebral abscess caused by Aggregatibacter aphrophilus and Actinomyces meyeri occurring a week post dental scaling. Both these bacteria are rarely involved in brain abscesses, and so far, cases of cerebral actinomyces have mostly been treated surgically and with intravenous (IV) antibiotics for 3-4 months, then put on oral antibiotic therapy with penicillin or amoxicillin for a further 3-12 months. Our patient underwent drainage through craniotomy and was subsequently put on intravenous ceftriaxone for 3 months accompanied by brain imaging control at the end of this period which showed complete regression of the abscess. Following parenteral treatment, no oral antibiotics were given since pharmacokinetic properties do not allow to attain high tissue concentration in the brain. This treatment gave excellent results.

An unusual case of multiple hepatic and pulmonary abscesses caused by Aggregatibacter aphrophilus in a young man: a case report.

BACKGROUND: Aggregatibacter aphrophilus, formerly known as Haemophilus aphrophilus, belongs to the HACEK organisms, a group of pathogens classically associated with infectious endocarditis. A. aphrophilus is a rarely found pathogen, though abscess formation in various organs has been described, typically due to spread from an infected heart valve. Here we describe the unusual case of multiple hepatic abscesses caused by A. aphrophilus. CASE PRESENTATION: A 33-year-old Caucasian man presented at our hospital with fever and malaise, elevated inflammatory markers, and liver enzymes. Imaging was compatible with multiple liver and pulmonary abscesses, without evidence of endocarditis. Cultures of blood and liver abscess material remained without growth. Polymerase chain reaction finally revealed Aggregatibacter aphrophilus in the liver tissue. The patient recovered fully within 6 weeks of doxycycline treatment. CONCLUSIONS: There are only a few case descriptions of liver abscesses caused by A. aphrophilus. As a ubiquitous organism in the gastrointestinal tract, A. aphrophilus may reach the liver via the portal venous system, as well as through hematogenous spread from the oropharynx. HACEK organisms are notoriously difficult to grow on culture, which highlights the diagnostic importance of eubacterial PCR.

Aggregatibacter aphrophilus spinal epidural abscess.

A 76-year-old woman with a rare case of spinal epidural abscess (SEA) that had no risk factors for such type of infection, presented symptoms of back pain, progressive neurological deficit of the lower limb and loss of sphincter control. A gadolinium-enhanced MRI confirmed the diagnosis of an SEA. The patient underwent laminectomy with surgical drainage, where cultures showed the presence of Aggregatibacter aphrophilus, a bacterium of the HACEK group (Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species), rarely involved in SEA. Following surgery, the patient was treated with intravenous ceftriaxone for 6 weeks, and this gave excellent results.

The First Known Case of Liver Abscess Caused by Aggregatibacter aphrophilus in Japan.

A 48-year-old man presented with a sustained fever. Abdominal computed tomography revealed multilocular liver abscesses. He underwent percutaneous needle aspiration, yielding straw-colored pus. Gram staining revealed Gram-negative coccobacilli. The organism grew only on chocolate II agar in a 7% carbon dioxide atmosphere. Identification of Aggregatibacter aphrophilus was confirmed using mass spectrometry and 16S rRNA gene sequencing. He was successfully treated with antibiotics. Liver abscess caused by A. aphrophilus is extremely rare. We herein report the first such case in Japan. Even fastidious organisms, such as A. aphrophilus, should be correctly identified using mass spectrometry or 16S rRNA gene sequencing for adequate treatment.

Polymicrobial Cerebral Abscess in a Child with Uncorrected Tetralogy of Fallot.

Aggregatibacter aphrophilus and Beta haemolytic Streptococci Lancefield group F are part of the normal oral flora and are known to cause endocarditis, sinusitis, empyema, meningitis and septic arthritis. They are now emerging as a cause of brain abscess particularly in patients with congenital heart diseases. We report a case of a 10-year-old boy with Tetralogy of Fallot (TOF), who presented with fever, headache and drowsiness. Culture yielded the growth of Aggregatibacter aphrophilus and Beta hemolytic streptococci Lancefield group F. He became clinically stable after treatment with ceftriaxone.

Dermacoccus sp. isolated from a brain abscess in a 4-year-old child.

Dermacoccus spp. have rarely been reported as human pathogens. We describe a case of a 4-year-old boy with congenital heart disease who was diagnosed with a brain abscess. The abscess was drained and the sample grew Streptococcus intermedius, Aggregatibacter aphrophilus and Dermacoccus sp.. Dermacoccus grew after 5 days of incubation and the patient was treated with meropenem.

[Septic arthritis byAggregatibacteraphrophilus: Case report] / Artritis séptica por Aggregatibacter aphrophilus.

Introduction: Septic arthritis by Aggregatibacter aphrophilus is an uncommon entity, so it's important to diagnose it early, to avoid serious consequences. In adults, the knee is the most affected site. Methods: We present a case of a 17-year-old boy, with pain in the left knee since one month ago. It shows an increase in local temperature, erythema and movement inability. A nuclear magnetic resonance (NMR) was performed and empirical treatment was given with cephalothin and clindamycin. A knee arthrotomy was realized, and intramedullary secretion and bone tissue was sent to study. Results: the NMR images were suggestive of an infectious process. In the culture gram-negative coccobacilli were isolated, later identified like as Aggregatibacter aphrophilus. According to this diagnostic, the treatment was changed to ceftriaxone The main conclusions: the rapidity and certainty in the choice of antimicrobial therapy is the most important step for a well evolution of this infection, therefore is very important to emphasize the importance of a correct identification of these rare microorganisms

Introducción: Aunque la artritis séptica es una entidad poco común, es importante debido a las graves consecuencias de un diagnóstico tardío o un incorrecto tratamiento. En adultos, la rodilla es el sitio más afectado. El objetivo de este trabajo es presentar un caso clínico de artritis séptica por Aggregatibacter aphrophilus en rodilla en un paciente joven, inmunocompetente, sin antecedentes patológicos. Materiales y métodos: Se estudia el caso de un joven de 17 años, tabaquista, con un cuadro de 1 mes de evolución caracterizado por gonalgia izquierda, aumento de la temperatura local, eritema e impotencia funcional. Se realizan análisis de sangre, una ecografía,y resonancia magnética (RMN).Se solicitan hemocultivos y cultivos de líquido intrarticular de rodilla. En la RMN se observa una lesión expansiva en la región femoral, sugestiva de un proceso infeccioso. Se comienza tratamiento empírico con cefalotina y clindamicina. Se realiza una artrotomia de rodilla enviándose para su estudio secreción endomedular, tejido óseo y endomedular. Resultados: Los hemocultivos y el cultivo del líquido intraarticular fueron negativos, pero los materiales obtenidos por técnica quirúrgica fueron positivos para el cultivo, aislándose cocobacilos gram negativos, posteriormente identificados como Aggregatibacter aphrophilus Se realizó el diagnóstico de artritis séptica por Aggregatibacter aphrophilus y se roto el tratamiento antimicrobiano a ceftriaxona. Conclusión: La rapidez y la certeza en la elección de la terapia antimicrobiana son un paso decisivo para la evolución de la enfermedad, por lo tanto se remarca la importancia de una correcta identificación de estos microorganismos poco frecuentes.

Exceptional association of two species of bacteria causing mediastinitis: Haemophilus influenzae (H. influenzae) and Aggregatibacter aphrophilus (A. aphrophilus).

BACKGROUND: Post cardiac surgery mediastinitis is the major infectious complication, despite the development of surgical techniques and the application of strict preventive measures. The Haemophilus influenzae mediastinitis is very rare. The mediastinitis caused by the association between Haemophilus influenzae and Aggregatibacter aphrophilus has never been described to our knowledge. CASE PRESENTATION: We report the case of an exceptional combination of Haemophilus influenzae and Aggregatibacter aphrophilus in a patient operated for single bypass which is complicated by mediastinitis the 10th day after the surgical act. CONCLUSION: The conclusion to be drawn from this work is to think in unusual seeds in case of mediastinitis post cardiac surgery for the elaboration of recommendations for antibiotic prophylaxis.

N-Glycosyltransferase from Aggregatibacter aphrophilus synthesizes glycopeptides with relaxed nucleotide-activated sugar donor selectivity.

N-Glycosyltransferase (NGT) is an inverting glycosyltransferase for an unusual pathway of N-linked protein glycosylation and glycosylates polypeptides in the consensus sequon (N-(X≠P)-T/S) with hexose monosaccharides. Here, we expressed and characterized a novel N-glycosyltransferase from Aggregatibacter aphrophilus (named AaNGT). RP-HPLC and Mass Spectrometry were used to assay and quantify glycopeptide formation by AaNGT and determine its substrate specificities. AaNGT could utilize a variety of nucleotide-activated sugar donors, including UDP-Glc, UDP-Gal, UDP-Xyl, GDP-Glc, dGDP-Glc and UDP-GlcN, to glycosylate the tested peptides. To the best of our knowledge, AaNGT was the first identified natural glycosyltransferase able to transfer GlcN moiety onto asparagine residues. AaNGT also exhibited a different position-specific residue preference of substrate peptides from the NGT of Actinobacillus pleuropneumoniae (ApNGT). In vitro assays with diverse synthesized peptides revealed that AaNGT preferred different peptide substrates from ApNGT. The efficient glycosylation of natural short peptides by AaNGT showed its potential to modify important therapeutic mammalian N-glycoproteins.

An unusual case of aggregatibacter aphrophilus liver abscess.

Liver abscess of oropharyngeal origin in an immunocompetent patient is a rare condition. Furthermore, microbiologic diagnosis of liver abscess can be challenging due to the tremendous diversity of the microorganisms implicated and culture difficulties under laboratory conditions. We report a case of a previously healthy 23-year-old male, who presented multiple liver abscesses, attributed to aggregatibacter aphrophilus, an obligatory oral gram-negative microorganism, that normally is a component of the commensal oral microbiota and non-virulent. The etiopathogenic microorganism was identified after needle aspiration of a liver abscess cavity. Treatment with broad-spectrum antimicrobials and percutaneous catheter drainage under computed tomography guidance of both abscesses, resulted in full recovery. A. aphrophilus represents a rare entity of liver abscess in healthy individuals and suggests that a pathogen of oropharyngeal origin should be suspected when an overt source of infection cannot be documented.

Genomic integration and expression of the Aggregatibacter actinomycetemcomitans catalase gene in Aggregatibacter aphrophilus.

OBJECTIVE: To test the hypothesis that virulence genes of Aggregatibacter actinomycetemcomitans can be expressed and confer fitness advantages in the closely related Aggregatibacter aphrophilus. DESIGN: Clinical isolates of A. aphrophilus were screened for natural competence with marked genomic DNA from A. actinomycetemcomitans and A. aphrophilus. The gene katA of A. actinomycetemcomitans D7S-1 and its flanking regions were constructed and inserted into a comparable locus in the genome of a naturally competent A. aphrophilus strain by a markerless protocol via natural transformation. Mutants of A. actinomycetemcomitans with or without katA were also constructed by a similar protocol. Discs soaked with either 0.03% hydrogen peroxide or broth culture of Streptococcus gordonii Challis were placed on the agar with cultures of A. actinomycetemcomitans or A. aphrophilus. The size of the growth inhibition zone associated with the disc was measured after 2-day culture. RESULTS: Five of the 13A. aphrophilus strains exhibited a transformation frequency of 10-6 or higher. The intra- and inter-species transformation frequencies were comparable. The inhibition zones for katA-negative strains of A. actinomycetemcomitans or A. aphrophilus were 3- to 7-fold larger than those associated with katA-positive strains (p<0.05). CONCLUSIONS: There was no apparent species barrier for the transfer and expression of A. actinomycetemcomitans katA in A. aphrophilus. The inserted A. actinomycetemcomitans-specific katA gene in A. aphrophilus strain NJ8700 conferred resistance to inhibition by hydrogen peroxide or S. gordonii. The potential to swap genes between these two closely related oral species may be an alternative approach for investigating the virulence determinants of A. actinomycetemcomitans.

[Endocarditis of mitral and aortic prosthetic heart valves caused by Aggregatibacter aphrophilus]. / Le cas clinique du mois. Endocardite à Aggregatibacter aphrophilus sur prothèses valvulaires.

We present the case of an acute endocarditis of mitral and aortic prosthetic heart valves caused by Aggregatibacter aphrophilus (Haemophilus aphrophilus-paraphrophilus). This third report in the literature emphasizes the diagnostic work-up and the role of positron emission tomography combined with computed tomography in this setting. The specificities of endocarditis due to the HACEK group (Haemophilus spp., Aggregatibacter, Cardiobacterium hominis, Eikenella corrodens and Kingella spp.) and the specific microbiological data and therapeutic options pertinent to this germ are discussed.

Nous rapportons la troisième observation clinique de la littérature d'une endocardite sur prothèses mécaniques mitrale et aortique due à l'Aggregatibacter aphrophilus (Haemophilus aphrophilus-paraphrophilus). Le pathogène récemment rebaptisé Aggregatibacter aphrophilus fait partie du groupe HACEK (Haemophilus spp., Aggregatibacter, Cardiobacterium hominis, Eikenella corrodens and Kingella spp.) impliqué dans des endocardites valvulaires de diagnostic difficile. Cette histoire clinique est l'occasion d'une revue de la littérature et des spécificités de ce pathogène. Elle met en exergue la contribution de la tomographie à émission de positons combinée à une tomodensitométrie dans le diagnostic et le suivi. Elle démontre, avec un recul de plus de deux ans, l'efficacité du traitement médical dans certaines endocardites sur prothèse.