Bloody diarrhea, STEC infection, and HUS in the molecular microbiology era.

Hemolytic uremic syndrome (HUS) associated with Shiga toxin-producing Escherichia coli (STEC) infection remains a major individual and public health challenge throughout the world causing substantial personal, social, and economic burdens. In Western countries, bloody diarrhea (BD) in children is related to STEC infection in at least 6% of cases (rising to 15-20% in summer). This infection may turn into STEC-HUS in about 15% of patients. The widespread use of molecular microbiology leads to the diagnosis of STEC infection before the onset of HUS in an increasing number of patients. The anticipation of the diagnosis creates a window of preventive and/or therapeutic opportunities that include rehydration of dehydrated patients and/or volume expansion that have both proven to mitigate the severity of HUS. Traditionally, antibiotics are not recommended in STEC infections, but recent data suggest a promising potential preventive role for bacteriostatic agents (e.g., azithromycin), if they are given early in the course of the infection. It is recommended to test all children with BD for Shiga toxin (Stx) encoding genes, actively infuse Stx-positive patients with isotonic crystalloid solutions and carefully monitor them with urine dipstick for hemoglobinuria to early identify those who might eventually develop HUS. The suggested approach will increase the detection of STEC-infected patients thus enhancing our knowledge of the mechanisms of disease spreading. The early diagnosis of STEC infection combined with the mentioned therapeutic opportunities will hopefully decrease the number of children suffering from HUS, its case fatality rate and/or improve its short- and long-term outcomes.