|Year : 2002 | Volume
| Issue : 4 | Page : 223-224
Satelliting streptococci in an adult male with foetal heart
SR Jayakeerthi , R Kanungo
Department of Neuromicrobiology, NIMHANS, Bangalore-560 029, India
Department of Neuromicrobiology, NIMHANS, Bangalore-560 029, India
Prior to the days of surgical correction and antibiotics, endocarditis was one of the leading causes of death in adults with patent ductus arteriosus (PDA). Satelliting Streptococcus is an important cause of "culture negative endocarditis". There are no earlier reports of this organism causing endocarditis in a case of PDA. Such a unique association, first of its kind, is reported here.
|How to cite this article:|
Jayakeerthi S R, Kanungo R. Satelliting streptococci in an adult male with foetal heart. Indian J Med Microbiol 2002;20:223-4
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Jayakeerthi S R, Kanungo R. Satelliting streptococci in an adult male with foetal heart. Indian J Med Microbiol [serial online] 2002 [cited 2020 Oct 28];20:223-4. Available from: https://www.ijmm.org/text.asp?2002/20/4/223/6963
Infective endocarditis (IE), infection of the cardiac valves or mural endocardium, can be fatal, if untreated. Congenital heart diseases including patent ductus arteriosus (PDA), ventricular septal defect (VSD) and tetralogy of fallot (TOF) are important predisposing factors for the IE to develop. The critical diagnostic finding in bacterial IE is bacteraemia. Blood cultures are positive in over 95% of patients with IE. But it may not always be possible to establish bacteraemia microbiologically. The condition popularly known as “culture negative endocarditis” can be due to many fastidious organisms such as nutritionally variant Streptococcus, L-forms and, HACEK group of organisms.
Satelliting Streptococcus was originally described by Frenkel and Hirsch in 1961 as new type of streptococci exhibiting satellitism around colonies of other bacteria. It was also called nutritionally variant Streptococcus due to its nutritional requirement for the growth and pyridoxal dependent streptococci and vitamin B6 dependent streptococci as they require the presence of pyridoxal hydrochloride (vitamin B6) for their growth. A new genus Abiotrophia was created to categorize these organisms in 1995. Abiotrophia means life nutrition deficiency and refers to the requirements of the species for supplemented media with vitamin B6 for growth. The genus Abiotrophia consists of two species i.e., A.defectives and A.adjacens. The term Abiotrophia will be used throughout this paper.
Abiotrophia species is one of the important causes of bacteraemia and bacterial endocarditis. It has also been isolated from cases of keratitis, corneal ulcers and oral ulcers. There is no case report of its association with infective endocarditis complicating patent ductus arteriosus, to the best of our knowledge.
| ~ Case report|| |
A 30-year-old male patient was admitted to this hospital in March 2001, with complaints of breathlessness and palpitations of 6 months duration, and fever for one week. There was no history of cough or chest pain. On examination, his pulse rate was 98/minute, blood pressure 130/78 mm Hg and temperature was 1010F. Auscultatory findings revealed muffled S1, S2 with a continuous murmur over aortic and pulmonary area. No other physical abnormality was detected. His haemoglobin was 9.6 grams % with normal mean corpuscular volume and mean corpuscular haemoglobin. White cell count was 13,000 cells/cu mm with 82% neutrophils. Serum electrolytes, blood urea, creatinine and liver enzymes were with in normal limits.
The chest radiograph showed a prominent aorta and pulmonary arterial system. Electrocardiogram studies suggested left atrial abnormality and left ventricular hypertrophy. Angiogram and echocardiogram suggested a large patent ductus arteriosus (PDA) with left to right shunt. There was no evidence of vegetation.
Blood culture was performed on clinical suspicion of infective endocarditis (IE). Five percent sheep blood agar (SBA) showed minute-hemolytic colonies alongside Staphylococcus aureus (ATCC 25923) streaking with characteristic satellitism. Gram smear from these satelliting colonies showed pleomorphic gram-positive cocci in pairs and short chains. With these findings the isolate was presumptively identified as Abiotrophia species. Other media such as 5% SBA without S.aureus streak, chocolate agar, 5% human BA and pyridoxal (0.001%) enriched SBA were also tried to evaluate their usefulness in cultivating this bacterium. The first two media failed to support the growth, whereas best growth was obtained on pyridoxal enriched SBA. The isolate was confirmed as, Abiotrophia species based on its enhanced growth on pyridoxal enriched medium and inability to grow on SBA with out S.aureus streak. Blood cultures done subsequently on next two consecutive days also yielded the same organism.
| ~ Discussion|| |
The association between PDA and IE was first documented in the early 1900s. The incidence has decreased in the later half of the last century, which has been largely attributed to the introduction of PDA ligation in 1939. There is little information in the contemporary medical literature about IE in PDA. In a 40-year review of bacterial endocarditis in Boston children's hospital between 1933 and 1972, only nine such cases were documented. In another review at children's medical centre of Dallas, between 1983 and 1992, none of the patients with IE had an associated PDA.
It may not always be possible to prove bacterial endocarditis microbiologically. The condition is popularly known as “culture negative endocarditis”. In some series it constituted 10-15% of clinically diagnosed cases of bacterial endocarditis; however many believe that the proportion is less (probably less than 5%). Abiotrophia species is an important cause of this condition. And it is very important to look for this organism in a clinically suspected case of bacterial endocarditis with the routine blood culture being sterile.
Our experience reemphasizes the importance of S.aureus streaking on SBA when used for blood culture. This helps in detection of Haemophilus influenzae and Abiotrophia species, two important bacteria associated with infections of human vascular system.
In vitro antibiotic susceptibility test using pyridoxal enriched SBA, showed the isolate to be sensitive to penicillin, ampicillin, cefotaxime, erythromycin, ciprofloxacin, chloramphenicol and gentamicin. The patient was treated with a combination of penicillin and gentamicin. He became afebrile after 4 days of therapy. Blood cultures performed subsequently were sterile. Triple ligation procedure was carried out later in order to correct the PDA.
| ~ References|| |
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