Resumo

Abiotrophia defectiva previously referred to as nutritionally variant streptococci, are found as part of the human normal flora colonizing oral, genitourinary, and intestinal tracts. It is the only specie belonging to the genus and presents itself mainly as Gram-positive cocci, but ovoid cells, and cocobacilli and bacilli may occur, depending on the culture medium. Cells are nonsporulating, nonmotile and facultative anaerobic. Bacteremia and endocarditis are the most frequently reported clinical infections due to this pathogen. Endocarditis caused by Abiotrophia accounted for 5% of all infectious endocarditis (IE) cases and 5% to 6% of all cases of streptococcal endocarditis. More recently, an increasing number of case reports described A. defectiva isolates recovered from invasive and noninvasive infections, during particular characteristics including dental procedures. We reported a fatal case of aortic valve endocarditis due to A. defectiva in patient exposed to pricking by fishbone. Four blood cultures were obtained in the teaching hospital where the patient was initially admitted. Positive blood cultures were inoculated in duplicate onto plates of chocolate agar medium supplemented with 1% Tween 80 and incubated at 37°C with and without CO2. Small dysmorphic pinpoints α-hemolytic colonies of Gram-positive cocobacilli were observed at 72h post-incubation. The Api Coryne System, GPI card and Vitek 2 system were used for biochemical species identification, according to the manufacturer's instructions. The GPI card and Vitek 2 detected with low plausibility the following clinical isolates: 7057 and 7059 as Alloiococcus otitis/Granulicatella elegans; 7058 as Gemella sanguinis/G. elegans and 7060 as G. elegans. In the API Coryne system, all four clinical isolates were identified as Erysipelothrix rhusiopathiae with 95% of probability. The definitive identification was established by 16S rRNA gene sequencing. The 16S rRNA sequences from the clinical isolates exhibited the highest similarity values to the type strain of A. defectiva (ATCC 49176), ranging from 98.96%-99.09%.