RETROSPECTIVE STUDY ON THE DISTRIBUTION OF E. COLI ENTERITIS IN BULGARIA FOR A PERIOD OF TEN YEARS (2011-2020)

BACKGROUND. Intestinal diseases caused by diarrheagenic E. coli account for a significant proportion of infections, especially in children. E. coli enteritis can occur as sporadic cases but often assumes an epidemic nature. This study aims to determine the significance and prevalence of infections caused by diarrheagenic E. coli in Bulgaria for a period of ten years 2011-2020. MATERIALS AND METHODS. The etiological role and distribution of diarrheagenic E. coli among Bulgarian population for the last decade were determined by a retrospective analysis of microbiological and epidemiological data. RESULTS. Data from the studied period reveal the role of enterotoxigenic E. coli (ETEC) O6 as a leading etiological cause of epidemic and sporadic enteritis in the country, followed by enteropathogenic E. coli (EPEC) O126 and O127. There are only two reported cases of lethal hemorrhagic uremic syndrome (HUS) caused by enterohemorrhagic E. coli (EHEC) that happened in 2011. Most affected by diarrheagenic E. coli (DEC) infections are infants and young children. Neonatal meningitis in Bulgaria is rare, the etiological agents are E. coli O18 and O25.  The most common registered DEC infections are during the summer months of May - September. Several epidemics have been registered in young children, and the etiological cause is ETEC O6. CONCLUSION. The main etiological agent of E. coli infections in Bulgaria is ETEC O6, and infants and young children are at risk. Recent DEC epidemics have not been reported. The ethiologic diagnosis of infections is underestimated, which is a risk factor for increasing the number of healthy carriers, outbreaks and unlimited agent spreading through the food chain.