Bacteriemias por Streptococcus gallolyticus (ex S. bovis) y su relación con patología colónica o hepatobiliar y endocarditis / Streptococcus gallolyticus (ex S. bovis) bacteremia and its relationship with colonic or hepatobiliary disease and endocarditis

Background: Bacteremia due to Streptococcus bovis (now S. gallolyticus) has been traditionally associated to colon or hepatobiliar disease and endocarditis but there is no information on this matter in Chile. Aims: To describe clinical features of adult patients suffering bacteremia by S. bovis/S. gallolyticus, identify the source of the bacteremia and the frequency of endocarditis. Methods: Retrospective-descriptive study using laboratory records. Results: Between January 2003 and August 2014, 23 S. bovis/S. gallolyticus bacteremic events were identified among 22 patients. Mean age was 72.7 years (range 46-96). Co-morbidities were frequent (9.1 to 47.6%). The primary source of bacteremia was intestinal in 52.2%; hepatobiliar in 17.4% and in 34.8% it was not elucidated. Six patients had infective endocarditis (26.1%) and one patient had espondylodiscitis (4.3%). S. bovis represented 39.1% of isolates (all until 2008), S. gallolyticus subsp pasteurianus 39.1% and, S. gallolyticus subsp infantarius and S. gallolyticus subsp gallolyticus 8.7% each one, respectively. Association studies between the bacteremic source or endocarditis with specific S. gallolyticus subspecies were limited by the small number of isolates. Seven patients (30.4%) underwent surgical interventions. In-hospital mortality reached 21.7% (n = 5). Conclusions: Although infrequent, bacteremic events by S. gallolyticus/S. bovis have increased in-hospital mortality, require surgical intervention and affect older patients with co-morbidities. Near two-thirds suffer from colonic or hepatobiliary disease that act as the primary source of bacteremia. In addition, near one fourth is affected by infective endocarditis. Detection of S. gallolyticus/S. bovis in blood cultures prompts a thorough clinical evaluation in order to clarify the source of the bloodstream infection and the presence of complications.

Antecedentes: Los cuadros de bacteriemia por Streptococcus bovis (actualmente S. gallolyticus) han sido tradicionalmente asociados a patología colónica o hepatobiliar y endocarditis pero no se conoce de estudios en Chile que hayan abordado este tema. Objetivos: Describir aspectos clínicos de pacientes adultos afectados por bacteriemias por S. bovis/S. gallolyticus, identificar la fuente de la bacteriemia y la frecuencia de endocarditis. Métodos: Diseño de tipo retrospectivo, descriptivo, con el registro de casos bacteriemia. Resultados: Entre enero de 2003 y agosto de 2014 se identificaron 23 eventos de bacteriemia por S. bovis/S. gallolyticus en 22 pacientes. La edad promedio fue de 72,7 años (rango 46-96). La prevalencia de diferentes co-morbilidades fue elevada (9,1 a 47,6%). El foco primario de la bacteriemia fue intestinal en 52,2%, hepatobiliar en 17,4% y, en 34,8% no se aclaró el foco. Seis pacientes presentaron endocarditis infecciosa (26,1%) y uno espondilodiscitis (4,3%). S. bovis representó 39,1% de los aislados (todos hasta el 2008), S. gallolyticus subsp pasteurianus 39,1%, S. gallolyticus subsp infantarius y S. gallolyticus subsp gallolyticus 8,7%, respectivamente. Los estudios de asociación estuvieron limitados por el bajo número de aislados. Siete pacientes (30,4%) debieron ser intervenidos quirúrgicamente. La mortalidad hospitalaria fue de 21,7% (n: 5). Conclusiones: Aunque infrecuentes, los eventos de bacteriemia por S. gallolyticus/S. bovis tienen una elevada mortalidad hospitalaria, requieren con frecuencia procedimientos quirúrgicos y afectan a pacientes mayores con co-morbilidades. Cerca de dos tercios padecen de una patología colónica o hepatobiliar que actúa como foco primario y cerca de un cuarto presenta endocarditis infecciosa. La detección de este grupo bacteriano en los hemocultivos requiere una evaluación para establecer el origen de la bacteriemia y la presencia de complicaciones.

New group D streptococcal species.

BACKGROUND & OBJECTIVES: The heterogeneity of group D streptococci led to the identification of various biotypes of Streptococcus equinus and Streptococcus bovis and to the description of new species. The objective of the present study was to improve the phenotypic delineation between species and to clarify their respective phylogenetic position. METHODS: Physiological and genomic analyses were carried out in 84 representative strains of the group D streptococci. Biotypes were determined with the API 20 strep and rapid ID 32 STREP systems of identification. Quantitative DNA-DNA hybridization under stringent conditions and values of the deltaT(m) allowed to delineate species and subspecies. The phylogenic position of the different genomic groups was determined by comparing the sequences of their 16S rDNA. RESULTS: Four DNA-clusters, including seven species or subspecies, were characterized. Differential associations of biochemical characters allowed their identification. S. equinus and the type strain of S. bovis belonged to a single species. S. gallolyticus, S. bovis biotype II.2, and S. macedonicus formed a single DNA-cluster including three different subspecies. These were designated as S. gallolyticus subsp. gallolyticus, S. gallolyticus subsp. pasteurianus, and S. gallolyticus subsp. macedonicus. The two other DNA-clusters corresponded to the two subspecies of S. infantarius, and to S. alactolyticus. INTERPRETATION & CONCLUSION: This study presented a new classification associated with an identification scheme of group D streptococci. The changes in this classification demonstrate the interest of a polyphagic approach of the bacterial identification.