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MBio Aug 2015Glycosylation is a widespread mechanism employed by both eukaryotes and bacteria to increase the functional diversity of their proteomes. The nontypeable Haemophilus...
UNLABELLED
Glycosylation is a widespread mechanism employed by both eukaryotes and bacteria to increase the functional diversity of their proteomes. The nontypeable Haemophilus influenzae glycosyltransferase HMW1C mediates unconventional N-linked glycosylation of the adhesive protein HMW1, which is encoded in a two-partner secretion system gene cluster that also encodes HMW1C. In this system, HMW1 is modified in the cytoplasm by sequential transfer of hexose residues. In the present study, we examined Kingella kingae and Aggregatibacter aphrophilus homologues of HMW1C that are not encoded near a gene encoding an obvious acceptor protein. We found both homologues to be functional glycosyltransferases and identified their substrates as the K. kingae Knh and the A. aphrophilus EmaA trimeric autotransporter proteins. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed multiple sites of N-linked glycosylation on Knh and EmaA. Without glycosylation, Knh and EmaA failed to facilitate wild-type levels of bacterial autoaggregation or adherence to human epithelial cells, establishing that glycosylation is essential for proper protein function.
IMPORTANCE
This work emphasizes the importance of glycosylation for proper function of bacterial proteins. Here we show that the Kingella kingae Knh and the Aggregatibacter aphrophilus EmaA trimeric autotransporter proteins are N-glycosylated by novel homologues of the Haemophilus influenzae HMW1C glycosyltransferase, highlighting the first examples of trimeric autotransporters that are modified by HMW1C-like enzymes. In the absence of glycosylation, Knh and EmaA lack adhesive activity. This work has relevance to our understanding of bacterial pathogenicity and expression of potential vaccine antigens.
Topics: Adhesins, Bacterial; Aggregatibacter aphrophilus; Amino Acid Sequence; Bacterial Adhesion; Chromatography, Liquid; Epithelial Cells; Glycopeptides; Glycosylation; Glycosyltransferases; Haemophilus influenzae; Humans; Kingella kingae; Molecular Sequence Data; Protein Structure, Tertiary; Tandem Mass Spectrometry; Type V Secretion Systems
PubMed: 26307167
DOI: 10.1128/mBio.01206-15 -
Journal of Microbiology, Immunology,... Dec 2021This study aimed to investigate the clinical characteristics and outcomes of bacteremia caused by Haemophilus and Aggregatibacter species in patients who were treated at...
BACKGROUND/PURPOSE
This study aimed to investigate the clinical characteristics and outcomes of bacteremia caused by Haemophilus and Aggregatibacter species in patients who were treated at a medical center between 2006 and 2018.
METHODS
Haemophilus and Aggregatibacter isolates were identified up to the species level using Bruker Biotyper MALDI-TOF analysis and ancillary 16S rRNA gene sequencing analysis (in case of ambiguity). Clinical characteristics and outcomes of patients with bacteremia caused by these organisms were evaluated.
RESULTS
Sixty-five Haemophilus and Aggregatibacter species isolates causing bacteremia were identified from nonduplicated patients, including 51 (78.5%) Haemophilus influenzae, 6 (9.2%) Haemophilus parainfluenzae, 1 (1.5%) Haemophilus haemolyticus, 3 (4.6%) A. aphrophilus, and 4 (6.2%) A. segnis. Hospital mortality was observed in 18 (28.1%) of 64 patients with bacteremia caused by Haemophilus (n = 57) and Aggregatibacter species (n = 7). The majority of patients with bacteremia had community-acquired disease with low severity. The average Sequential Organ Failure Assessment (SOFA) score was low (4.4 ± 4.7). But, a higher SOFA score (adjusted odds ratio 2.5, 95% confidence interval 1.22-5.12; P = 0.01) was an independent factor predicting poor 7-day clinical outcomes in patients with community-acquired H. influenzae bacteremia (n = 39).
CONCLUSIONS
The overall hospital mortality of 28.1% was observed among patients with bacteremia due to Haemophilus and Aggregatibacter species. A higher SOFA score was and independent predictor of poor 7-day clinical outcomes in patients with community-acquired H. influenzae bacteremia.
Topics: Adult; Aged; Aggregatibacter; Anti-Bacterial Agents; Bacteremia; Female; Haemophilus; Hospital Mortality; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Organ Dysfunction Scores; RNA, Ribosomal, 16S
PubMed: 33390332
DOI: 10.1016/j.jmii.2020.12.002 -
Infection and Drug Resistance 2022is part of the normal flora in the oropharynx and upper respiratory tract, which causes invasive bacteremia in rare cases. However, the culture and identification of...
is part of the normal flora in the oropharynx and upper respiratory tract, which causes invasive bacteremia in rare cases. However, the culture and identification of are challenging, hence easily misdiagnosed or undetected in clinical practice. In this case, a 73-year-old male patient was admitted to the hospital with a fever and right hip pain. Routine blood and C-reactive protein tests showed abnormal inflammatory markers. Positive blood culture revealed the presence of through mass spectrometry. The computed tomography examination further revealed the presence of psoas abscess, pulmonary infection, and pleural effusion, which was relieved by ceftriaxone combined with levofloxacin therapy, the drainage of psoas abscess and pleural effusion. Therefore, since multiple anatomic sites infection, including bloodstream, psoas abscess and pulmonary infection caused by is rare, sufficient attention should be paid to its clinical diagnosis and treatment.
PubMed: 36262594
DOI: 10.2147/IDR.S381360 -
Journal of Medical Microbiology Dec 2022are Gram-negative, facultatively anaerobic rods or coccobacilli that are infrequently encountered as pathogens causing infection. The range of invasive infection that...
are Gram-negative, facultatively anaerobic rods or coccobacilli that are infrequently encountered as pathogens causing infection. The range of invasive infection that cause is poorly described. The pathogenicity of species such as is debated. To identify invasive infection due to species in a large healthcare organization and to characterize clinical syndromes, co-morbidities and risk factors. All microbiological samples positive for species were identified by conventional culture or 16S rRNA PCR between October 2017 and March 2021. Electronic records for all patients with positive samples were reviewed and the infection syndrome classified for patients with invasive disease. Twenty-seven patients with invasive infection were identified, with a statistically significant difference in species-specific patterns of invasive infection (=0.02) and a statistically significant association with residence in the 30 % most deprived households in the UK by postcode (<0.01). The three most common co-morbidities were periodontitis or recent dental work (29.6%), cardiovascular disease (25.9%) and diabetes (18.5 %). We describe a novel association of with skin and soft tissue infection. The propensity of the species to cause invasive infection at different body sites and be associated with deprivation is reported. bacteraemia was associated with infective endocarditis, and was implicated in severe appendicitis and noted to cause brain abscess. Areas warranting future research include exploring the risk-factors required for invasive infection and those that may determine the species-specific differences in patterns of invasive disease.
Topics: Humans; Aggregatibacter; Retrospective Studies; RNA, Ribosomal, 16S; Endocarditis, Bacterial
PubMed: 36748613
DOI: 10.1099/jmm.0.001612 -
Clinical Neurology and Neurosurgery Aug 2022Aggregatibacter aphrophilus(A. aphrophilus)is one of the organisms of the HACEK group. Previously reported cases of brain abscesses caused by A. aphrophilus... (Review)
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.
Topics: Adult; Aggregatibacter aphrophilus; Anti-Bacterial Agents; Brain Abscess; Child; Endocarditis; Female; Heart Defects, Congenital; Heart Septal Defects, Atrial; Humans; Hypertension, Pulmonary; Meropenem; Middle Aged; Pasteurellaceae Infections; Vancomycin
PubMed: 35717764
DOI: 10.1016/j.clineuro.2022.107337 -
Journal of Medical Case Reports Feb 2021Aggregatibacter aphrophilus, formerly known as Haemophilus aphrophilus, belongs to the HACEK organisms, a group of pathogens classically associated with infectious...
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.
Topics: Adult; Aggregatibacter aphrophilus; Humans; Liver Abscess; Lung Abscess; Male; Pasteurellaceae Infections
PubMed: 33536074
DOI: 10.1186/s13256-020-02650-z -
IDCases 2020previously , is an uncommon organism that historically has been associated with HACEK infective endocarditis and brain abscesses. This organism is most often isolated...
previously , is an uncommon organism that historically has been associated with HACEK infective endocarditis and brain abscesses. This organism is most often isolated as part of normal oral flora, and patients with infection usually have an underlying periodontal infection or immunocompromised state allowing for infection. This case report outlines a unique presentation of left superficial temporal abscess due to infection in an immunocompetent individual.
PubMed: 32346513
DOI: 10.1016/j.idcr.2020.e00753 -
Retinal Cases & Brief Reports Jan 2024To describe a rare case of unilateral, endogenous endophthalmitis caused by Aggregatibacter aphrophilus (HACEK group) confirmed in vitreous and blood cultures, in a...
PURPOSE
To describe a rare case of unilateral, endogenous endophthalmitis caused by Aggregatibacter aphrophilus (HACEK group) confirmed in vitreous and blood cultures, in a patient with dentophobia.
METHODS
Case report.
PATIENTS
A seventy-five-year-old male patient with Type 2 diabetes, previous myocardial infarction, and pacemaker implantation.
RESULTS
Patient was observed with sudden loss of vision at the Department of Ophthalmology, Uppsala University. Initial diagnosis was posterior vitreous detachment and anterior uveitis, but progression of disease led to vitrectomy, which actually demonstrated endophthalmitis and growth of A. aphrophilus of the HACEK group. Aggregatibacter bacteremia and pacemaker endocarditis were also identified and dental examination confirmed growth of Aggregatibacter in the oral cavity. Intravitreal treatment with ceftazidime and vancomycin according to Endophthalmitis Vitrectomy Study protocol was administered with quick resolution of endophthalmitis.
CONCLUSION
Aggregatibacter endophthalmitis is a rare, but devastating cause of vision loss where immediate diagnosis may be delayed. Prompt diagnosis may be facilitated by a thorough medical history and early vitreous biopsy. Systemic investigation by an infectious disease specialist and multidisciplinary assessment are mandatory. Ophthalmologic treatment is effective with intravitreal injections of ceftazidime and vancomycin.
Topics: Male; Humans; Aged; Ceftazidime; Anti-Bacterial Agents; Vancomycin; Aggregatibacter; Diabetes Mellitus, Type 2; Dental Anxiety; Endophthalmitis; Vitrectomy; Eye Infections, Bacterial
PubMed: 36007190
DOI: 10.1097/ICB.0000000000001335 -
Journal of Microbiology, Immunology,... Feb 2016We report on a rare case of Aggregatibacter aphrophilus brain abscess of odontogenic origin in a 6-year-old previously healthy boy, who had close contact with a pet dog.... (Review)
Review
We report on a rare case of Aggregatibacter aphrophilus brain abscess of odontogenic origin in a 6-year-old previously healthy boy, who had close contact with a pet dog. The poodle was the most likely source of the infecting organism, which subsequently colonized the patient's oral cavity. The abscess was surgically removed and he recovered completely after prolonged antibiotic treatment with meropenem. We also review the relevant medical literature on A. aphrophilus pediatric brain abscesses.
Topics: Aggregatibacter aphrophilus; Animals; Anti-Bacterial Agents; Brain Abscess; Child; Debridement; Dogs; Humans; Male; Pasteurellaceae Infections; Tooth Extraction; Tooth, Deciduous; Treatment Outcome
PubMed: 24529567
DOI: 10.1016/j.jmii.2013.12.007 -
IDCases 2019is a rare cause of infective endocarditis that was first described in 1940 by Khairat et al. and is now classified under the HACEK group of bacteria ( spp. spp.. There...
is a rare cause of infective endocarditis that was first described in 1940 by Khairat et al. and is now classified under the HACEK group of bacteria ( spp. spp.. There is limited literature describing the extracardiac complications of infective endocarditis caused by this organism. We report a case of a 53-year-old male with no significant past medical history who developed acute infective endocarditis complicated by a brain abscess caused by . The patient underwent aspiration of the abscess and treated with a long course of intravenous antimicrobials. This case represents a rare complication of infective endocarditis caused by A. aphrophilus and to the best of our knowledge, is the second reported case in the literature describing such a complication in a previously healthy patient. Although neurological sequela is associated with higher mortality and may be the presenting symptom of infective endocarditis, it may also be clinically silent - only detected upon imaging.
PubMed: 31193507
DOI: 10.1016/j.idcr.2019.e00561