Prevalence, characterisation and clinical profiles of Shiga toxin-producing Escherichia coli in The Netherlands

Abstract

Detection of Shiga toxin-producing Escherichia coli (STEC) in The Netherlands is traditionally limited to serogroup O157. To assess the relative importance of STEC, including non-O157 serogroups, stool samples submitted nationwide for investigation of enteric pathogens or diarrhoea were screened with real-time PCR for the presence of the Shiga toxin genes. Patients were selected if their stool contained blood upon macroscopic examination, if they had a history of bloody diarrhoea, were diagnosed with haemolytic uraemic syndrome, or were aged <6 years (irrespective of the bloody aspect of the stool). PCR-positive stools were forwarded to a central laboratory for STEC isolation and typing. In total, 4069 stools were examined, with 68 (1.7%) positive PCR results. The highest prevalence was for stools containing macroscopic blood (3.5%), followed by stools from patients with a history of bloody diarrhoea (2.4%). Among young children, the prevalence (1.0%) was not significantly higher than among random, non-bloody, stool samples from diarrhoeal patients (1.4%). STEC strains were isolated from 25 (38%) PCR-positive stools. Eleven O-serogroups were detected, including five STEC O157 strains. As serogroup O157 represented only 20% of the STEC isolates, laboratories should be encouraged to use techniques enabling them to detect non-O157 serogroups, in parallel with culture, for isolation and subsequent characterisation of STEC strains for public health surveillance and detection of outbreaks.

Assessing the Public Health Risk of Shiga Toxin-Producing Escherichia coli by Use of a Rapid Diagnostic Screening Algorithm

“…Although the disease severity and incidence of STEC are not based solely on the pathogenic potential of the organism but also on host-associated and environmental factors, enough information has accumulated that the presence of virulence factors (VF) carried in addition to the stx genes varies considerably between STEC strains and, therefore, could be used to categorize the potential risk of STEC (5,17,(33)(34)(35)(36). The detection frequency of the stx genes observed in this study (1.8%) was comparable with previous studies performed in The Netherlands (30,37). The diagnostic algorithm enabled the categorization of STEC infections into 4 pathotype (PT) groups.…”

Improved Detection of Five Major Gastrointestinal Pathogens by Use of a Molecular Screening Approach

“…Previous studies also reported improvements in the detection rate of enteric pathogens by molecular assays (1,7,18,25,36,37,40). The reason why S. enterica was the only pathogen not detected more frequently by MSA than by culture (3.0%) may be the use of a sensitive selective enrichment broth.…”

“…Other studies have reported higher success rates for STEC isolation by culture if serotypes other than O157 are also searched for (14,15,40). But in the routine laboratory, STECs other than O157 cannot be detected by means other than PCR aimed at the stx 1 and/or stx 2 genes.…”

“…For the detection of enteric pathogens it has been proven feasible to use molec-ular methods with improved performance and turnaround time (TAT) (7,25,32 MATERIALS AND METHODS mPCR technical validation. All primers and probes used for detection of the five enteric pathogens were previously described (4,21,34,43,45), and for some we previously performed extensive clinical validations (32,33,40). For validation of the mPCR, a total of 147 bacterial/fungal strains were used in selectivity testing.…”

Incidence and Virulence Determinants of Verocytotoxin-Producing Escherichia coli Infections in the Brussels-Capital Region, Belgium, in 2008–2010

“…Global "hot spots," in which non-O157 serotypes predominate over O157, include France (51), Germany (2), Spain (5), The Netherlands (60), and Belgium (50). In 2010, the European Center for Disease Prevention and Control (ECDC) reported 3,160 confirmed VTEC cases, or 0.66 infection per 100,000 persons (13a).…”