CONICET | Buscador de Institutos y Recursos Humanos

Shiga toxin type 2 (Stx2) are mainlyproduced by Shiga toxin?producing Escherichia coli (STEC) that ithas been reported to be highly pathogenic and to be associatedwith 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 tomicrovesicles. The aim was to detect plasma Stx2 bounded tomicrovesicles (MVs-Stx2) in a patient with Shigellosis andsystemic complications. A 10-year-old girl was admitted to thehospital because of mucous diarrhea with bloody stretch marksover two days. Her laboratory admission showed normalhematocrit, hemoglobin and platelet count. Renal function wasconserved without hematuria and proteinuria. Coproculturesample was positive for Shigella flexneri. Two days afteradmission, hematocrit (30.7 %), hemoglobin (9.8 g/dl) andplatelet count (187,000/mm3) were decreased. Take into accountthis results it was suspected a development of HUS. A peripheralblood smear was performed and did not show schistocytosis. Weobtained blood samples in order to detect the presence of plasmaStx2. Samples were sequentially ultracentrifuged to obtainmicrovesicles (MVs)-enriched suspension. Then, MVs carryingStx2 were analyzed by flow cytometry. Data are expressed asthe percentage of positives MVs-Stx2. From the controls, a cutoff range for MVs-Stx2 was established (1.02-1.90 %, n= 5). Asignificant higher percentage of MVs-Stx2 (13.6 %) wasdetected. The patient was not present renal function alterationsduring this time. These results indicate that the systemicalterations observed in this patient could be explain by theeffects of circulating Stx2, like happens in patients withincomplete HUS (absence of kidney disorders) Based on this, it isessential to incorporate Stx2 detection to patients with bacterialinfection such as Shigellosis

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