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BMJ Case Rep. 2010; 2010: bcr1120092462.
Published online Jul 22, 2010. doi:  10.1136/bcr.11.2009.2462
PMCID: PMC3029670
Other full case
Actinobacillus actinomycetemcomitans endocarditis in a 1.5 year old toddler
Ayelet Shles,1 Baruch Wolach,1 Alex Levi,2 and Giora Gottesman3
1Department of Pediatrics, Meir Hospital, Kfar Saba, Israel
2Department of Cardiology, Meir Hospital, Kfar Saba, Israel
3Pediatric Infectious Diseases – Sapir Medical Center, Meir Hospital, Kfar Saba, Israel
Correspondence to Giora Gottesman, gotesmang/at/clalit.org.il
The authors report a 1.5-year-old girl who developed Actinobacillus actinomycetemcomitans (AA) endocarditis involving the pulmonic valve. She had a congenital cardiac abnormality, but no history of dental manipulation. The case illustrates an uncomplicated course with three unique features; the youngest reported infant with endocarditis caused by AA with vegetation on the pulmonic valve. She underwent a benign course with complete recovery.
The authors report a 1.5-year-old girl who developed AA endocarditis involving the pulmonic valve. She had a congenital cardiac abnormality, but no history of dental manipulation. The case illustrates an uncomplicated course with three unique features; the youngest reported infant with endocarditis caused by AA with vegetation on the pulmonic valve. She underwent a benign course with complete recovery.
Actinobacillus actinomycetemcomitans (AA) is grouped in the HACEK group of bacteria (Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens and Kingella kingae), which is considered to be the most common cause of paediatric Gram-negative infective endocarditis.1
Members of this group of bacteria cause 3% of all cases of paediatric endocarditis,1 and possess similar traits; they are all small, slow-growing Gram-negative bacteria, which produce similar clinical syndromes that are often insidious.
The HACEK microbes are frequent colonizers of the oral cavity and may cause periodontal infections.2 In addition to endocarditis, AA may cause head and neck infections, brain abscesses, pneumonia, soft tissue infections and urethritis.
AA was first described as an aetiological agent in endocarditis in 1964, by Mitchell and Gillespie.3 Only a few additional cases have been reported. A review based on a MEDLINE search of all previous reports of AA endocarditis found 102 such cases. The youngest patient mentioned in this review was 7 years old.4 Another review of HACEK endocarditis in children reported five additional cases of AA endocarditis, with the youngest patient being 7 years old.5
Case presentation
A 1.5-year-old infant was admitted with a 7-day history of fever, chills and general weakness. She had undergone open valvuloplasty 6 months prior to the current hospitalization, due to a congenital cardiac malformation; double outlet, right ventricle, VSD and pulmonic stenosis. The postoperative course was uncomplicated.
She had no history of dental manipulation.
An initial physical examination showed a fever of 40°C and the cardiac examination revealed grade 3/6 systolic and diastolic murmurs. There were no peripheral signs of endocarditis.
Investigations
The white blood cell count and platelet count were normal. The haemoglobin was 9.8 g/dl, and the erythrocyte sedimentation rate was 105 mm/h.
There was no microscopic haematuria and serum creatinine was normal.
The transthoracic echocardiogram (TTE) revealed pulmonic valve vegetation.
Six blood cultures were drawn on the day of admission, and one of them grew an actinomycetemcomitans on the seventh day following admission. The organism was sensitive to ampicillin and ceftriaxone.
Differential diagnosis
Most common organisms that cause infective endocarditis in children are Gram-positive cocci, including viridans group (α-haemolytic) streptococci (Streptococcus sanguis, Streptococcus mitis group, Streptococcus mutans, etc), staphylococci and enterococci. Enterococcal endocarditis occurs much less frequently in children than in adults. Less common are Gram-negative organisms such as the HACEK group. Culture-negative infective endocarditis comprises around 6% of cases in children.1
Treatment
On the first day of hospitalization, intravenous garamycin, vancomycin and cloxacillin were initiated. This regimen was replaced by ceftriaxone according to sensitivity.
Outcome and follow-up
The patient became afebrile on the second day. After 6 days, a repeated TTE was conducted and revealed no change. Repeated blood cultures were sterile. The patient was discharged and continued parental antibiotics as an outpatient for a total of 4 weeks.
Twenty-two days from initiation of treatment, the TTE showed no vegetation and the patient was asymptomatic.
AA is a very rare cause of endocarditis, and only a few well-described cases have been reported. AA is a fastidious, Gram-negative coccobacillus that forms part of the normal oral flora and can gain entry to the vascular compartment via dental infection, dental procedures or spontaneous bacteraemia resulting from mastication – the latter being the most frequent.6 Our patient did not exhibit any oral-dental insult.
The mean age of patients previously reported with AA endocarditis was 46 years.4 The youngest patient described was 7 years old.4 Our case of AA endocarditis presents the youngest reported patient diagnosed with this condition.
Most children with HAECK endocarditis have pre-existing cardiac abnormalities similar to our patient. We have not found any reported case of pulmonic valve involvement in AA endocarditis. Among reported cases of AA endocarditis in adults and children, the aortic and mitral valves were involved most often.4
Our patient underwent a benign course, although patients diagnosed with AA endocarditis are at great risk for complications. An explanation for the higher prevalence of complications with AA may be attributed to the relatively long duration of infection before diagnosis.7 The isolated pathogen in the current case was highly susceptible to antibiotics and no B-lactamase production was noted as reported in previous cases of AA isolations.8
Learning points
  • AA endocarditis can cause a mild course.
  • AA endocarditis can involve the pulmonic valve.
  • AA endocarditis can occur in toddlers.
Footnotes
Competing interests None.
Patient consent Obtained.
1. Ferrieri P, Gewitz MH, Gerber MA, et al. Unique features of infective endocarditis in childhood. Circulation 2002;105:2115–26. [PubMed]
2. Das M, Badley AD, Cockerill FR, et al. Infective endocarditis caused by HACEK microorganisms. Annu Rev Med 1997;48:25–33. [PubMed]
3. Paturel L, Casalta JP, Habib G, et al. Actinobacillus actinomycetemcomitans endocarditis. Clin Microbiol Infect 2004;10:98–118. [PubMed]
4. Paturel L, Casalta JP, Habib G, et al. Actinobacillus actinomycetemcomitans endocarditis. Clin Microbiol Infect 2004;10:98–118. [PubMed]
5. Feder HM, Jr, Roberts JC, Salazar JC, et al. HACEK endocarditis in infants and children: two cases and a literature review. Pediatr Infect Dis J 2003;22:557–62. [PubMed]
6. Guntheroth WG. How important are dental procedures as a cause of infective endocarditis? Am J Cardiol 1984;54:797–801. [PubMed]
7. Das M, Badley AD, Cockerill FR, et al. Infective endocarditis caused by HACEK microorganisms. Annu Rev Med. 1997;48:25–33. [PubMed]
8. Madinier IM, Fosse TB, Hitzig C, et al. Resistance profile survey of 50 periodontal strains of Actinobacillus actinomycetemcomitans. J Periodontol 1999;70:888–92. [PubMed]
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