Escherichia coli O104:H4
Strain of bacteria
From Wikipedia, the free encyclopedia
Escherichia coli O104:H4 is an enteroaggregative Escherichia coli serovar of the bacterium Escherichia coli, and the cause of the 2011 Escherichia coli O104:H4 outbreak.[1] The "O" in the serological classification identifies the cell wall lipopolysaccharide antigen, and the "H" identifies the flagella antigen.
| Escherichia coli O104:H4 | |
|---|---|
Scientific classification | |
| Domain: | Bacteria |
| Kingdom: | Pseudomonadati |
| Phylum: | Pseudomonadota |
| Class: | Gammaproteobacteria |
| Order: | Enterobacterales |
| Family: | Enterobacteriaceae |
| Genus: | Escherichia |
| Species: | E. coli |
| Serovar: | E. c. O104:H4 |
| Trionomial name | |
Escherichia coli O104:H4 | |
Analysis of genomic sequences obtained by BGI Shenzhen shows that the O104:H4 outbreak strain is an enteroaggregative E. coli (EAEC or EAggEC) type that has acquired Shiga toxin genes, presumably by horizontal gene transfer.[2][3][4]
Genome assembly and copy-number analysis both confirmed that two copies of the Shiga toxin stx2 prophage gene cluster are a distinctive characteristic of the genome of the O104:H4 outbreak strain.[5][6] The O104:H4 strain is characterized by these genetic markers:[6][7]
- Shiga toxin stx2 positive
- tellurite resistance gene cluster positive
- intimin adherence gene negative
- β-lactamases ampC, ampD, ampE, ampG, ampH are present.
The European Commission (EC) integrated approach to food safety[8] defines a case of Shiga-like toxin-producing E. coli (STEC) diarrhea caused by O104:H4 by an acute onset of diarrhea or bloody diarrhea together with the detection of the Shiga toxin 2 (Stx2) or the Shiga gene stx2.[9]
Prior to the 2011 outbreak, only one case identified as O104:H4 had been observed, in a woman in South Korea in 2005.[10]
Pathophysiology
E. coli O104 is a Shiga toxinâproducing E. coli (STEC). The toxins cause illness and the associated symptoms by sticking to the intestinal cells and aggravating the cells along the intestinal wall.[11][12] This, in turn, can cause bloody stools to occur. Another effect from this bacterial infection is hemolytic uremic syndrome (HUS), which is a condition characterized by destruction of red blood cells, that over a long period of time can cause kidney failure.[13] Some common symptoms of HUS are vomiting, bloody diarrhea, and blood in the urine.[12]
Infection
A common mode of E. coli O104:H4 infection involves ingestion of fecally contaminated food; the disease can thus be considered a foodborne illness. Most recently in 2011, an outbreak of the O104:H4 strain in Germany caused the deaths of several people, and hundreds were hospitalised.[14][15][12] German authorities traced the infection back to fenugreek sprouts grown from contaminated seeds imported from Egypt, but these results are debated.[citation needed]
Diagnosis
To diagnose infection with STEC, a patient's stool (feces) can be tested in a laboratory for the presence of Shiga toxin. Testing methods used include direct detection of the toxin by immunoassay, or detection of the stx2 gene or other virulence-factor genes by PCR. If infection with STEC is confirmed, the E. coli strain may be serotyped to determine whether O104:H4 is present.[11]
Treatment
E. coli O104:H4 is difficult to treat as it is resistant to many antibiotics, although it is susceptible to carbapenems.[14]
Prevention
Spread of E. coli is prevented simply by thorough hand-washing with soap, washing and hygienically preparing food, and properly heating/cooking food, so the bacteria are destroyed.[16]