Escherichia coli O104:H4

Escherichia coli O104:H4 is a rare enterohemorrhagic strain 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.

Analysis of genomic sequences obtained by BGI Shenzhen show 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 the following genetic markers:^[6][7]

• Shiga toxin stx2 positive,
• terE positive (tellurite resistance gene cluster),
• eae negative (intimin adherence gene),
• 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 toxin–producing E. coli (STEC). These toxins are what cause us to become sick. The method of how these toxins make us sick is they stick to the intestinal cells and aggravate the cells along the intestinal wall.^[11][12] This in turn usually can cause bloody stools to occur. Other effects that can come from this bacteria is Hemolytic uremic syndrome (HUS). Which is a condition characterized by destruction of red blood cells and this over a long period of time can cause kidney failure develop.^[13]Some common symptoms of HUS are vomiting, bloody diarrhea, and blood in the urine.^[14]

Infection

How someone becomes infected with such a resistant bacteria like the E. Coli O104:H4, is when food with contaminated feces is consumed; meaning this illness is typically food born. Most recently in 2011, there was an outbreak of the E. Coli O104:H4 strain in Germany that caused dozens to die, and landed hundreds of US citizens in the hospital.^[15][16][17] The infection was eventually traced back to some sprouts that had been contaminated.

Treatment

The first step to treating someone that appears to have E. Coli O104:H4 symptoms are to test their stools. The stool test is then sent a lab to see if it has any remnants of STEC (Shiga-toxin–producing E. coli) can be found; if STEC is found it is a good chance that E. Coli O104:H4 or another form of STEC is present. With the help of lab tests a doctor can diagnose a patient so they can properly be treated. One thing that makes E. Coli O104:H4 very difficult to treat is that it is resistant to most antibiotics except carbapenems; in fact, E. Coli O104:H4 is resistant to at least 14 different types of antibiotics.^[18]

Prevention

The biggest thing that we can do to prevent the spread of such virulent bacteria such as E. Coli O104:H4 is by doing simple things which include: washing our hands, washing our food, and properly cooking our food so we can be sure that the majority pathogenic bacterium are destroyed.^[19]

References