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Expert Review of Anti-infective Therapy 2016The HACEK group of bacteria - Haemophilus parainfluenzae, Aggregatibacter spp. (A. actinomycetemcomitans, A. aphrophilus, A. paraphrophilus, and A. segnis),... (Review)
Review
The HACEK group of bacteria - Haemophilus parainfluenzae, Aggregatibacter spp. (A. actinomycetemcomitans, A. aphrophilus, A. paraphrophilus, and A. segnis), Cardiobacterium spp. (C. hominis, C. valvarum), Eikenella corrodens, and Kingella spp. (K. kingae, K. denitrificans) - are fastidious gram-negative bacteria, part of the normal microbiota of oral and upper respiratory tract in humans. Although their pathogenicity is limited, they are responsible for 1-3% of all infective endocarditis. HACEK endocarditis mostly affect patients with underlying heart disease or prosthetic valves, and are characterized by an insidious course, with a mean diagnosis delay of 1 month (Haemophilus spp.) to 3 months (Aggregatibacter and Cardiobacterium spp.). The advent of continuously monitored blood culture systems with enriched media has erased the need for extended incubation for the diagnosis of HACEK endocarditis. Medical treatment relies on third-generation cephalosporin, with a favorable outcome in 80-90% of cases, with or without cardiac surgery.
Topics: Cephalosporins; Endocarditis, Bacterial; Gram-Negative Bacteria; Humans; Risk Factors
PubMed: 26953488
DOI: 10.1586/14787210.2016.1164032 -
BMJ Case Reports May 2013A 61-year-old patient with diabetes had a bio-prosthetic aortic valve replacement 3 years before admission. He complained of lethargy, night sweats, decreased appetite...
A 61-year-old patient with diabetes had a bio-prosthetic aortic valve replacement 3 years before admission. He complained of lethargy, night sweats, decreased appetite and erratic blood glucose with no weight loss. He had splinter haemorrhage and a systolic ejection murmur at the aortic area. Chest and abdominal examination revealed no abnormality. The erythrocyte sedimentation rate and C reactive protein were raised. He had several sets of blood cultures and he was started on empirical vancomycin, rifampicin and gentamicin. Transthoracic echocardiography showed vegetation on the base of the anterior mitral leaflet, which was confirmed by a trans-oesophageal echocardiography. Blood culture was positive for Haemophilus aphrophilus, and he was started on ceftriaxone for 6 weeks instead of vancomycin and rifampicin and continued gentamicin for 2 weeks. Follow-up echocardiography showed no evidence of vegetations. The patient recovered completely and he was discharged home.
Topics: Aggregatibacter aphrophilus; Anti-Bacterial Agents; Ceftriaxone; Endocarditis, Bacterial; Humans; Male; Middle Aged; Pasteurellaceae Infections
PubMed: 23682079
DOI: 10.1136/bcr-2012-007359 -
Archivos Peruanos de Cardiologia Y... 2023Infective endocarditis is a serious disease associated with high mortality despite recent advances in diagnosis and treatment. is a fastidious Gram-negative member of... (Review)
Review
Infective endocarditis is a serious disease associated with high mortality despite recent advances in diagnosis and treatment. is a fastidious Gram-negative member of the HACEK organisms ( spp., , , , and ). is associated with dental infections but has also been implicated in cases of infective endocarditis. We highlight the importance of a high index of suspicion in symptomatic patients with an initial negative blood culture, particularly in high-risk groups such as patients with congenital valve disease and prosthetic valve. The knowledge of this rare entity may lead to early diagnosis and appropriate management. We review the main characteristics of endocarditis reported in the medical literature.
PubMed: 38046225
DOI: 10.47487/apcyccv.v4i3.306 -
Journal of Clinical Medicine Nov 2021A virulent genotype (JP2) of the periodonto-pathogen, (), is widespread in North and West Africa, while its presence in East Africa has not been thoroughly...
BACKGROUND
A virulent genotype (JP2) of the periodonto-pathogen, (), is widespread in North and West Africa, while its presence in East Africa has not been thoroughly investigated. This JP2 genotype is associated with periodontitis in adolescents and has a high leukotoxicity. The aim of the study was to examine the prevalence of and its JP2 genotype, the prevalence of the oral, commensal in a Maasai adolescent population, and the effect of herbal plants for inhibition of leukotoxicity.
METHODS
A total of 284 adolescents from Maasai Mara, Kenya, underwent an oral examination and microbial sampling. The presence of and was analyzed by quantitative PCR and cultivation (the 58 samples collected at the last day of field study). The collected strains were characterized and leukotoxin promoter typed. Additionally, herbal plants commonly used for oral hygiene were assessed for the inhibition of leukotoxicity.
RESULTS AND CONCLUSIONS
The prevalence of in stimulated whole saliva was high (71.8%), with the JP2 genotype detected in one individual, and in 99% of the sampled individuals. The commonly used herbal plant, , inactivated leukotoxicity. The virulence might be reduced through use of and the high levels of .
PubMed: 34830683
DOI: 10.3390/jcm10225402 -
Journal of Oral Microbiology 2019and belong to the HACEK group of fastidious Gram-negative organisms, a recognized cause of infective endocarditis. is also implicated in aggressive forms of...
and belong to the HACEK group of fastidious Gram-negative organisms, a recognized cause of infective endocarditis. is also implicated in aggressive forms of periodontitis. We demonstrated that strains, as are ubiquitously serum resistant. Both species encode two Outer membrane protein A paralogues, here denoted OmpA1 and OmpA2. As their respective pangenomes contain several OmpA1 and OmpA2 alleles, they represent potential genotypic markers. A naturally competent strain of and , respectively were used to elucidate if OmpA1 and OmpA2 contribute to serum resistance. Whereas OmpA1 was critical for survival of D7SS in 50% normal human serum (NHS), serum resistant mutants were fortuitously obtained, expressing enhanced levels of OmpA2. Similarly, OmpA1 rather than OmpA2 was a major contributor to serum resistance of HK83. Far-Western blot revealed that OmpA1, OmpA2, and OmpA1 can bind to C4-binding protein, an inhibitor of classical and mannose-binding lectin (MBL) complement activation. Indeed, mutants were susceptible to these pathways, but also to alternative complement activation. This may at least partly reflect a compromised outer membrane integrity but is also consistent with alternative mechanisms involved in OmpA-mediated serum resistance.
PubMed: 30598730
DOI: 10.1080/20002297.2018.1536192 -
Archives of Oral Biology Feb 2018To test the hypothesis that virulence genes of Aggregatibacter actinomycetemcomitans can be expressed and confer fitness advantages in the closely related...
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 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.
Topics: Aggregatibacter actinomycetemcomitans; Aggregatibacter aphrophilus; Catalase; Gene Transfer Techniques; Genomic Islands; Genomics; Hydrogen Peroxide; Mutagenesis, Insertional; Polymerase Chain Reaction; Virulence
PubMed: 29223024
DOI: 10.1016/j.archoralbio.2017.12.002 -
Clinical Microbiology Reviews Apr 2014The aim of this review is to provide a comprehensive update on the current classification and identification of Haemophilus and Aggregatibacter species with exclusive or... (Review)
Review
The aim of this review is to provide a comprehensive update on the current classification and identification of Haemophilus and Aggregatibacter species with exclusive or predominant host specificity for humans. Haemophilus influenzae and some of the other Haemophilus species are commonly encountered in the clinical microbiology laboratory and demonstrate a wide range of pathogenicity, from life-threatening invasive disease to respiratory infections to a nonpathogenic, commensal lifestyle. New species of Haemophilus have been described (Haemophilus pittmaniae and Haemophilus sputorum), and the new genus Aggregatibacter was created to accommodate some former Haemophilus and Actinobacillus species (Aggregatibacter aphrophilus, Aggregatibacter segnis, and Aggregatibacter actinomycetemcomitans). Aggregatibacter species are now a dominant etiology of infective endocarditis caused by fastidious organisms (HACEK endocarditis), and A. aphrophilus has emerged as an important cause of brain abscesses. Correct identification of Haemophilus and Aggregatibacter species based on phenotypic characterization can be challenging. It has become clear that 15 to 20% of presumptive H. influenzae isolates from the respiratory tracts of healthy individuals do not belong to this species but represent nonhemolytic variants of Haemophilus haemolyticus. Due to the limited pathogenicity of H. haemolyticus, the proportion of misidentified strains may be lower in clinical samples, but even among invasive strains, a misidentification rate of 0.5 to 2% can be found. Several methods have been investigated for differentiation of H. influenzae from its less pathogenic relatives, but a simple method for reliable discrimination is not available. With the implementation of identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry, the more rarely encountered species of Haemophilus and Aggregatibacter will increasingly be identified in clinical microbiology practice. However, identification of some strains will still be problematic, necessitating DNA sequencing of multiple housekeeping gene fragments or full-length 16S rRNA genes.
Topics: Aggregatibacter; Bacteriological Techniques; Haemophilus; Haemophilus Infections; Host Specificity; Humans; Molecular Diagnostic Techniques; Pasteurellaceae Infections; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 24696434
DOI: 10.1128/CMR.00103-13 -
BMJ Case Reports Jul 2020A 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...
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 , a bacterium of the HACEK group ( species, species, , , and species), rarely involved in SEA. Following surgery, the patient was treated with intravenous ceftriaxone for 6 weeks, and this gave excellent results.
Topics: Aged; Aggregatibacter aphrophilus; Anti-Bacterial Agents; Ceftriaxone; Epidural Abscess; Female; Humans; Laminectomy; Pasteurellaceae Infections; Postoperative Complications; Spine
PubMed: 32675123
DOI: 10.1136/bcr-2020-235320 -
Journal of Dental Research Jan 2016Gram-negative facultative Aggregatibacter actinomycetemcomitans is an oral pathogen associated with periodontitis. The genetic heterogeneity among A.... (Comparative Study)
Comparative Study
Gram-negative facultative Aggregatibacter actinomycetemcomitans is an oral pathogen associated with periodontitis. The genetic heterogeneity among A. actinomycetemcomitans strains has been long recognized. This study provides a comprehensive genomic analysis of A. actinomycetemcomitans and the closely related nonpathogenic Aggregatibacter aphrophilus. Whole genome sequencing by Illumina MiSeq platform was performed for 31 A. actinomycetemcomitans and 2 A. aphrophilus strains. Sequence similarity analysis shows a total of 3,220 unique genes across the 2 species, where 1,550 are core genes present in all genomes and 1,670 are variable genes (accessory genes) missing in at least 1 genome. Phylogenetic analysis based on 397 concatenated core genes distinguished A. aphrophilus and A. actinomycetemcomitans. The latter was in turn divided into 5 clades: clade b (serotype b), clade c (serotype c), clade e/f (serotypes e and f), clade a/d (serotypes a and d), and clade e' (serotype e strains). Accessory genes accounted for 14.1% to 23.2% of the A. actinomycetemcomitans genomes, with a majority belonging to the category of poorly characterized by Cluster of Orthologous Groups classification. These accessory genes were often organized into genomic islands (n = 387) with base composition biases, suggesting their acquisitions via horizontal gene transfer. There was a greater degree of similarity in gene content and genomic islands among strains within clades than between clades. Strains of clade e' isolated from human were found to be missing the genomic island that carries genes encoding cytolethal distending toxins. Taken together, the results suggest a pattern of sequential divergence, starting from the separation of A. aphrophilus and A. actinomycetemcomitans through gain and loss of genes and ending with the divergence of the latter species into distinct clades and serotypes. With differing constellations of genes, the A. actinomycetemcomitans clades may have evolved distinct adaptation strategies to the human oral cavity.
Topics: Aggregatibacter actinomycetemcomitans; Aggregatibacter aphrophilus; Bacterial Toxins; Base Composition; DNA, Bacterial; DNA, Concatenated; Evolution, Molecular; Gene Transfer, Horizontal; Genes, Bacterial; Genetic Heterogeneity; Genetic Speciation; Genetic Variation; Genome, Bacterial; Genomic Islands; Humans; Mouth; Phylogeny; Protein Subunits; Sequence Analysis, DNA; Serogroup
PubMed: 26420795
DOI: 10.1177/0022034515608163 -
The New Microbiologica May 2023We 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....
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.
Topics: Female; Humans; Adult; Aggregatibacter aphrophilus; Eikenella corrodens; Endocarditis, Bacterial; Anti-Bacterial Agents; Brain Abscess
PubMed: 37247244
DOI: No ID Found