Detection of shiga toxin type 2 binds to microvesicles in the plasma simple of a patient with shigellosis

MELINA PORPORATO; FERNANDO GOMEZ; ELSA ISERN; FLAVIA SACERDOTI; MARIA MARTA AMARAL; CRISTINA IBARRA; ELZA ZOTTA

Mar del Plata

Congreso; Reunión Anual de Biociencia 2019; 2019

Sociedad Argentina de Investigación Clínica

Shiga toxin type 2 (Stx2) are mainly produced by Shiga toxin?producing Escherichia coli (STEC) that it has been reported to be highly pathogenic and to be associated with hemorrhagic colitis hemolytic and uremic syndrome (HUS). At this moment, an early method of diagnosis of HUS is not exist. Our laboratory developed a method of detection of Stx2 bind to microvesicles. The aim was to detect plasma Stx2 bounded to microvesicles (MVs-Stx2) in a patient with Shigellosis and systemic complications. A 10-year-old girl was admitted to the hospital because of mucous diarrhea with bloody stretch marks over two days. Her laboratory admission showed normal hematocrit, hemoglobin and platelet count. Renal function was conserved without hematuria and proteinuria. Coproculture sample was positive for Shigella flexneri. Two days after admission, hematocrit (30.7 %), hemoglobin (9.8 g/dl) and platelet count (187,000/mm3) were decreased. Take into account this results it was suspected a development of HUS. A peripheral blood smear was performed and did not show schistocytosis. We obtained blood samples in order to detect the presence of plasma Stx2. Samples were sequentially ultracentrifuged to obtain microvesicles (MVs)-enriched suspension. Then, MVs carrying Stx2 were analyzed by flow cytometry. Data are expressed as the percentage of positives MVs-Stx2. From the controls, a cut-off range for MVs-Stx2 was established (1.02-1.90 %, n= 5). A significant higher percentage of MVs-Stx2 (13.6 %) was detected. The patient was not present renal function alterations during this time. These results indicate that the systemic alterations observed in this patient could be explain by the effects of circulating Stx2, like happens in patients with incomplete HUS (absence of kidney disorders) Based on this, it is essential to incorporate Stx2 detection to patients with bacterial infection such as Shigellosis.