Abstract
IntroductionAt the beginning of 2016, an increase in paediatric haemolytic uremic syndrome (HUS) cases was observed in Romania. The microbiological investigations allowed isolation of Shiga toxin-producing Escherichia coli (STEC) O26 as the causative agent from most cases. Methods: An enhanced national surveillance of HUS and severe diarrhoea was established across the country following the identification of the first cases and was carried out until August 2016. A total of 15 strains were isolated from 10 HUS and five diarrhoea cases. Strains were characterised by virulence markers (i.e. stx type/subtype, eae, ehxA genes), phylogroup, genetic relatedness and clonality using PCR-based assays, PFGE and multilocus sequence typing (MLST). The first six strains were further characterised by whole genome sequencing (WGS). Results: Five PCR-defined genotypes were distinguished. All strains from HUS cases harboured stx2a and eae, with or without stx1a, while strains from diarrhoea cases carried exclusively stx1a and eae genes. PFGE resolved strains into multiple pulsotypes, compatible with a certain geographic segregation of the cases, and strains were assigned to phylogroup B1 and sequence type (ST) 21. WGS confirmed the results of conventional molecular methods, brought evidence of O26:H11 serotype, and complemented the virulence profiles. Discussion/conclusion: This first description of STEC O26 strains from cases in Romania showed that the isolates belonged to a diverse population. The virulence content of most strains highlighted a high risk for severe outcome in infected patients. Improving the national surveillance strategy for STEC infections in Romania needs to be further considered.
Highlights
At the beginning of 2016, an increase in paediatric haemolytic uremic syndrome (HUS) cases was observed in Romania
The study collection included 15 Shiga toxin-producing Escherichia coli (STEC) O26 strains isolated from cases with HUS (n = 10), bloody diarrhoea (n = 1) or non-bloody diarrhoea (n = 4) reported across Romania between February and June 2016
This study focuses on the microbiological characterisation of STEC O26 strains isolated from cases identified in Romania during a community-wide outbreak of STEC-associated HUS [13]
Summary
At the beginning of 2016, an increase in paediatric haemolytic uremic syndrome (HUS) cases was observed in Romania. STEC of serotype O157:H7 are those most often associated with epidemics of STEC infections worldwide [2,3,4] and most likely to cause severe infections with systemic complications such as haemolytic uremic syndrome (HUS) [5]. STEC O26 poses a significant threat to human health in terms of illness severity and the risk of causing outbreaks. This serogroup is considered emerging in Europe and in the last decade, it was reported as the most frequent non-O157 STEC serogroup in human sporadic cases of infection, including those developing HUS [9]. In 2013, the emergence of a highly virulent clone of STEC O26 strongly associated with HUS in Europe was described in the scientific literature [11]
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