EU case definition: HUS caused by epidemic strain Shiga toxin 2-producing Escherichia Coli

EU case definition for diarrhoea and haemolytic uremic syndrome (HUS) caused by the epidemic strain Shiga toxin 2-producing Escherichia Coli (STEC) O104:H4
 

Possible epidemic case

Any person who developed on or after May 1, 2011:

STEC diarrhoea defined as

  • Acute onset of diarrhoea or bloody diarrhoea

AND

  • At least one of the following laboratory criteria:
    • Isolation of an E. coli strain that produces Shiga toxin 2 (Stx2) or harbours stx2 gene;

    • Direct detection of stx2 gene nucleic acid in faeces without strain isolation.

STEC HUS defined as

  • Haemolytic Uremic Syndrome (HUS) defined as acute renal failure and at least one of the following clinical criteria:
  • Microangiopatic haemolytic anaemia,
  •  Thrombocytopenia.
  •  

Probable epidemic case

Any person meeting the criteria for a possible case of STEC diarrhoea or STEC HUS

AND

During the exposure period of 14 days before the onset of illness, meeting at least one of the following epidemiological criteria:

  • Stay in Germany or any other country where a confirmed case has probably acquired infection;
  • Consumption of food product obtained from Germany;
  • Close contact (e.g., in a household) with a confirmed epidemic case.
  •  

Confirmed epidemic case

Any person meeting the criteria for a possible case,

AND

Isolation of a STEC strain of serotype O104:H4

OR

Isolation of a STEC strain of serotype O104 AND fulfilling epidemiological criteria for a probable case

Characterisation of the outbreak strain

The outbreak strain has the following characteristics [1]:

  • Shiga toxin –producing E. coli of serotype O104:H4
  • Shiga toxin 2a+ (Stx2a positive)
  • Intimin, eae - (negative )
  • Enterohaemolysin - (negative)

EaggEC Virulence plasmid:

  • aatA-PCR: + (positive) (ABC-transporter protein gene)
  • aggR-PCR: + (positive) (master regulator gene of Vir-plasmid genes)
  • aap-PCR: + (positive) (secreted protein dispersin gene)
  • aggA-PCR: + (positive) (AAF/I-fimbral subunit-gene)
  • aggC-PCR: + (positive) (AAF/I-fimbral operon-gene)

MLST sequence type:

ST678 (adk 6, fumC6, gyrB 5, icd 136, mdh 9, purA 7, recA 7)
ESBL production (CTX-M-15)

Further characterization of the STEC strain should be performed if possible by testing for:

  • full serotype;
  • eae and aggR genes;
  • subtype stx2 and genotyping by MLST;
  • XbaI PFGE;
  • ESBL (Extended Spectrum Beta-Lactamase).
  •  

Exclusion criteria

All other serotypes than the outbreak strain are excluded. Also strains producing Stx1 or being positive for stx1 gene are excluded.

Recommendation for reporting cases for outbreak monitoring at EU level

Please report number of probable and confirmed cases and deaths as mutually exclusive clinical categories according to the table below (table 1). The number of deaths should be included in the number of epidemic cases.

Table 1: Cumulative number of cases and deaths of STEC diarrhoea and STEC HUS caused by or linked to the epidemic strain STEC O104:H4

 

STEC diarrhoea

STEC HUS

TOTAL

 

Number of

cases

Number of

Deaths*

Number of

cases

Number of

Deaths*

Number of

cases

Number of

Deaths*

Probable

case

 

 

 

 

 

 

Confirmed

case

 

 

 

 

 

 

Total

 

 

 

 

 

 

*Death is due to illness caused by STEC or HUS related to the outbreak and the number of deaths should be included in the number of cases

References

1. http://www.rki.de/cln_109/nn_467482/DE/Content/InfAZ/E/EHEC/EHEC__Diagnostik