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A Brief Synopsis of A Brief Synopsis of “HACEK” organisms“HACEK” organisms
Michael AddidleMichael Addidle
HACEK ORGANISMSHACEK ORGANISMS
H-H-H. parainfluenzaeH. parainfluenzae A-Aggregatibacter A-Aggregatibacter
actinomycetecomitansactinomycetecomitans - Aggregatibacter aphrophilus and - Aggregatibacter aphrophilus and
paraphrophilus.paraphrophilus. C-Cardiobacterium hominusC-Cardiobacterium hominus E-Eikenella corrodensE-Eikenella corrodens K-Kingella speciesK-Kingella species
What do HACEK organisms have in What do HACEK organisms have in common?common?
Gram negativeGram negative Commensals in oropharyngeal areaCommensals in oropharyngeal area Relatively fastidiousRelatively fastidious Prefer CO2 enriched atmospherePrefer CO2 enriched atmosphere All have a propensity to cause endocarditis, usually All have a propensity to cause endocarditis, usually
secondary to rotten teeth or recent dental treatment or secondary to rotten teeth or recent dental treatment or combination of both.combination of both.• Endocarditis- long interval between first symptoms and Endocarditis- long interval between first symptoms and
dx.dx.• Frequent embolisationFrequent embolisation• May be large vegetations on left sided valves.May be large vegetations on left sided valves.
Can all cause non-endocardial infections also.Can all cause non-endocardial infections also.
Haemophilus parainfluenzaeHaemophilus parainfluenzae
H. aphrophilus and H. H. aphrophilus and H. paraphrophilus have movedparaphrophilus have moved
Cause endocarditis more commonly Cause endocarditis more commonly than H. influenzae but all than H. influenzae but all endocarditis caused by Haemophilus endocarditis caused by Haemophilus is rare.is rare.
A-Aggregatibacter A-Aggregatibacter actinomycetecomitansactinomycetecomitans
Common cause of periodontitisCommon cause of periodontitis Most endocarditis caused by this Most endocarditis caused by this
bacteria have underlying heart bacteria have underlying heart disease.disease.
Star-shaped coloniesStar-shaped colonies
Cardiobacterium hominisCardiobacterium hominis
In contrast to other members of the In contrast to other members of the group, almost exclusively associated group, almost exclusively associated with endocarditiswith endocarditis
May also be commensal of GI tractMay also be commensal of GI tract Characteristic Gram stain: bulbous Characteristic Gram stain: bulbous
ends and irregular staining. May ends and irregular staining. May have a rosette pattern.have a rosette pattern.
..
Eikenella corrodensEikenella corrodens
Oral commensal. May implicated in bite Oral commensal. May implicated in bite infections.infections.
May cause infections at several different May cause infections at several different sites within the body.sites within the body.
Slightly yellow colonies after a few daysSlightly yellow colonies after a few days Bleach like odourBleach like odour Pit into agar.Pit into agar. Beta-lactamase strains are not infrequent.Beta-lactamase strains are not infrequent.
Eikenella corrodensEikenella corrodens
Kingella speciesKingella species K. kingae, K dentrificans, K.oralis, K. potusK. kingae, K dentrificans, K.oralis, K. potus Square ends, uneven decolorisation on Gram Square ends, uneven decolorisation on Gram
stain.stain. May be mildly haemolytic on blood agarMay be mildly haemolytic on blood agar Colonise pharynx of many children 6 months to Colonise pharynx of many children 6 months to
4 years.4 years. Common cause of septic arthritis in this age Common cause of septic arthritis in this age
group.group. Infections in adults usually in Infections in adults usually in
immunocompromised. immunocompromised. Injection of aspirate into BC media improves Injection of aspirate into BC media improves
detection rates.detection rates.
Kingella speciesKingella species
Kingella speciesKingella species
Molecular detectionMolecular detection
In modern blood culture systems, In modern blood culture systems, HACEK organsims grow within 5 HACEK organsims grow within 5 days.days.
16s PCR16s PCR Most useful for heart valvesMost useful for heart valves May also be useful for negative blood May also be useful for negative blood
cultures where high index of cultures where high index of suspicion.suspicion.