ABSTRACT
A case of bacteremia in a 74-year-old man, which was caused by Pasteurella dagmatis and complicated by thrombocytopenia, is presented. Microorganism identification was performed by the provincial reference laboratory using traditional biochemical profiling, completmented with both the sequencing of the 16S ribosomal RNA gene and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; antibiotic-susceptibility testing was also performed. After treatment with the appropriate antibiotics, the patient fully recovered. Systemic infections attributed to this organism are rarely reported in the literature. Other reported cases of bacteremia due to P dagmatis are reviewed and compared with the present case. The challenges of relying on standard automatic identification are discussed, with alternative methodologies provided.
Les auteurs présentent un cas de bactériémie chez un homme de 74 ans, causé par un Pasteurella dagmatis et compliqué par une thrombocytopénie. Le laboratoire de référence provincial a identifié le microorganisme au moyen du profilage biochimique classique et l'a complété par le séquençage du gène de l'ARN ribosomique 16S et par la spectrométrie de masse à temps de vol par désorption-ionisation laser assistée par matrice. Le laboratoire a également effectué un test de susceptibilité aux antibiotiques. Après un traitement antibiotique pertinent, le patient s'est complètement rétabli. Les publications scientifiques contiennent peu de déclarations d'infections systémiques attribuées à cet organisme. D'autres cas de bactériémie à P dagmatis sont analysés et comparés à la présente situation. Les problèmes liés à l'identification automatique standard sont exposés et d'autres méthodologies sont proposées.
ABSTRACT
The biological and clinical significance of circulating tumor cells (CTC) in the peripheral blood of breast cancer patients is not known. To study this question, we used a direct visualization assay to correlate the number of CTC with disease stage and progression. The CTC were enriched from the nucleated cell fraction by filtration and enumerated visually following immunostaining with anti-cytokeratin 8 (CK8) antibody CAM 5.2. In mixing experiments, we achieved a limit of detection of 5 MCF7 cells per 5 ml of blood or 5 x 10(7) peripheral blood leukocytes (PBL). We did not detect CTC in any control subjects (0/20). In 131 breast cancer patients, we found a higher incidence of CTC in patients with distant metastatic 36/51 (71%) than those with node-positive 17/36 (47%) (p = 0.026), or node-negative 17/44 (39%) (p = 0.001) disease. The distribution of the highest numbers of CTC observed in individual patients by repeated sampling over time ranged from 1 to 700 per 5 ml of blood with a trend toward higher numbers in those with distant metastases. In comparison with previous studies of equal specificity, based on a similar absence of CTC in controls, we report a higher incidence of CTC in node-negative and node-positive patients, suggesting a more frequent detection of CTC by our approach. This higher incidence was achieved, in part, by repeated sampling of our study population over time. Our results support the concept that CTC can be detected and enumerated in peripheral blood and that this minimally invasive assay merits further evaluation as a potential prognostic indicator and marker of disease progression.
