A 78-year-old woman hospitalized for investigation of ascites presented with weakness, loss of appetite, fever, and chills. A complete blood count showed anemia, leukocytosis, and thrombocytopenia (hemoglobin, 8.5 g/dL; leukocytes, 27.5 × 109/L; platelets, 50 × 109/L). Peripheral blood smear demonstrated the presence of neutrophilia with left shift (promyelocytes, 0.3 × 109/L; myelocytes, 1.9 × 109/L; metamyelocytes, 2.2 × 109/L; band neutrophils, 2.2 × 109/L; and segmented neutrophils, 19.7 × 109/L) and distorted granulocytes containing toxic vacuoles and intracellular structures that exhibit a uniform and definite rod shape (arrows), suggestive of phagocytized bacilli (panels A-B). Blood cultures confirmed the blood smear findings and revealed the presence of 2 species of bacillus, Klebsiella pneumoniae and Pseudomonas aeruginosa.

The finding of microorganisms in peripheral blood smear is unusual and should be regarded as a useful indicator of overwhelming infection, supporting an early and definitive diagnosis of septicemia. Although several species of bacteria have been described on examination of peripheral blood smears, detection of bacteremia due to gram-negative rods on a blood film has rarely been reported.

A 78-year-old woman hospitalized for investigation of ascites presented with weakness, loss of appetite, fever, and chills. A complete blood count showed anemia, leukocytosis, and thrombocytopenia (hemoglobin, 8.5 g/dL; leukocytes, 27.5 × 109/L; platelets, 50 × 109/L). Peripheral blood smear demonstrated the presence of neutrophilia with left shift (promyelocytes, 0.3 × 109/L; myelocytes, 1.9 × 109/L; metamyelocytes, 2.2 × 109/L; band neutrophils, 2.2 × 109/L; and segmented neutrophils, 19.7 × 109/L) and distorted granulocytes containing toxic vacuoles and intracellular structures that exhibit a uniform and definite rod shape (arrows), suggestive of phagocytized bacilli (panels A-B). Blood cultures confirmed the blood smear findings and revealed the presence of 2 species of bacillus, Klebsiella pneumoniae and Pseudomonas aeruginosa.

The finding of microorganisms in peripheral blood smear is unusual and should be regarded as a useful indicator of overwhelming infection, supporting an early and definitive diagnosis of septicemia. Although several species of bacteria have been described on examination of peripheral blood smears, detection of bacteremia due to gram-negative rods on a blood film has rarely been reported.

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