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Marler Blog Providing Commentary on Food Poisoning Outbreaks & Litigation

Pulsed Field Gel Electrophoresis Pattern of E. coli O104:H4 in German Outbreak

The current EHEC O104:H4, causing a severe outbreak in Germany (May 2011), is microbiologically characterized as follows (1) (27.5.2011; updated 30.5.2011):

Shigatoxin 1: – (negative), Shigatoxin 2 (vtx2a): + (positive), Intimin (eae): – (negative), Enterohemolysin: – (negative)

EaggEC Virulence plasmid:  –   aatA-PCR: + (positive),  –   aggR-PCR: + (positive),  –   aap-PCR: + (positive)

MLST Sequence Type:  ST678 (adk 6, fumC6, gyrB 5, icd 136, mdh 9, purA 7, recA 7). (**)

(**) MLST: kindly provided by Prof. Dr. H. Karch; Konsiliarlaboratorium für Hämolytisch-Urämisches Syndrom (HUS) Institut für Hygiene am Universitätsklinikum Münster Robert-Koch-Str. 41, 48149 Münster

Ampicillin  R

Amoxicillin/Clavulanic acid  R

Piperacillin/Sulbactam  R

Piperacillin/Tazobactam  R*

Cefuroxim  R

Cefuroxim-Axetil  R

Cefoxitin  R

Cefotaxim  R

Cetfazidim  R

Cefpodoxim  R

Imipenem  S

Meropenem  S

Amikacin  S

Gentamicin  S

Kanamycin  S

Tobramycin  S

Streptomycin  R

Nalidixinsäure  R

Ciprofloxacin  S

Norfloxacin  S

Tetracyclin  R

Nitrofurantoin  S

Trimethoprim/Sulfamethoxazol  R

Chloramphenicol  S

Fosfomycin  S

* defined as resistent (AES VITEK)

ESBL: + (CTX-M (Group 1), Other ß-Lactamases: TEM-Type +

Macrorestriction pattern (XbaI) from human E. coli O104:H4 isolates from the current outbreak

Screen shot 2011-05-31 at 8.23.05 PM.png

PFGE according to Prager et al. (2011) IJMM 301:181-191.

Lanes 1 and 5 MW-Standard Salmonella Braenderup H9812. Lane 2: RKI-11-02027 (HUS), Lane 3: RKI-11-02034 (diarrhea), Lane 4: RKI-11-02060 (bloody diarrhea).

1) Source: Nationales Referenzzentrum für Salmonellen und andere bakterielle Enteritiserreger; Robert Koch-Institut; Abteilung 1 Infektionskrankheiten

  • Daniel B. Cohen

    What does the above genetic elements and resistance pattern say about the origin of the strain? To a non-expert like me, the following:

    First, that it does not follow the pattern of broad surveys of non-O157:H7 STEC in animals and humans such as in “Phenotypic and genotypic characterization of verotoxin-producing Escherichia coli O103:H2 isolates from cattle and humans.”
    Karama M, Johnson RP, Holtslander R, Gyles CL (EU and N. America) and “Antimicrobial resistance testing of verocytotoxin-producing Escherichia coli and first description of TEM-52 extended-spectrum β-lactamase in serogroup O26” .Buvens G, Bogaerts P, Glupczynski Y, Lauwers S, Piérard D (Belgium).

    Second, the absence of stx-1 and the presence of stx-2a (VT 2a) as well as the resistance pattern suggests human origin in a carrier infected by (or carrying) a virulent HUS strain. See the above articles and the research on monoclonal antibodies targeting stx-2 as therapeutic treatments for HUS at the Uniformed Services University (O’Brien lab) and Caprion/Ecopia.

    Third, this would suggest greater investigation emphasis on contamination at washing-repacking facilities, possibly in Hamburg, including worker health status, conditions of work, or physically inappropriate design allowing contamination (based on testimony and outbreak investigation reports surrounding O157:H7 in spinach). This may be non-standard procedure for a presumed food-borne outbreak.

    But I would recommend asking Carlton Gyles at Guelph, or others, who are expert to look at the data pattern.

    Dan Cohen
    Maccabee Seed Company
    Davis, CA

  • Minkpuppy

    For a non-expert, you’ve got some very good points, Mr. Cohen. You definitely have a better idea than I do on how to interpret the data here.

    I wonder how many outbreaks have actually been caused by a sick worker or even an asymptomatic carrier? Has it even been considered in outbreaks where they can’t seem to pinpoint a source?

    I’m thinking of Typhoid Mary but only with E. coli. Will we eventually find out that humans can carry and shed the bacteria just like cattle do without becoming ill? Sounds like a good thesis for a microbiology grad student to me.

  • Guy H Loneragan, Texas Tech University

    It appears that E. coli O104:H4 with a MLST Sequence Type=ST678 was observed approximately 10 years previously in Germany in a HUS case.

    Like the current outbreak strain, it was stx2 positive and eae negative. I am unsure of the status with the EaggEC Virulence plasmid in the 2001 isolate.

    Please see manuscript published in Emerging Infectious Diseases: Vol. 14, No. 8, August 2008 http://www.cdc.gov/eid/content/14/8/pdfs/1287.pdf

  • Anonymous

    anybody working with E. coli O104:H4 at the University of Hamburg ??

  • Robert LaBudde

    Rather than hypothecate an ill worker contaminating wash water (which would likely only lead to a few sporadic cases), consider the possibility of use of unpasteurized human waste as a fertilizer. This would more likely lead to a large scale outbreak.