Seattle-area family ill with E. coli
Elisa Hahn with KING 5 News in Seattle interviewed a Seattle-area family that has become ill with E. coli O157:H7. The question is - where? Public health officials and health care providers are trying to determine where the family picked up the bacterium, but have not yet come up with any answers. As Hahn reported:
First, 16-month-old Adelido started to show symptoms of e. coli two weekends ago. Then, 3-year-old Carlitos became ill a few days later."Let's just say, lots of bloody stools, lots of blood, mucousy blood, fever, very sleepy, not themselves,” described their mother, Cairn Alfonso-Slevin.
Right after both boys got out of the hospital, their grandmother who often babysits them checked into the hospital with the same symptoms.
Infection with E. coli O157:H7 is usually confirmed by detecting the bacterium in the stool of the infected individual. Most hospital labs and physicians know to test for this particular bacterium, especially if the potentially infected individual has bloody diarrhea. Still, it remains a good idea to specifically request that a stool specimen be tested with Sorbitol MacConkey (SMAC) Agar for the presence of E. coli O157:H7.
In addition, E. coli O157:H7 is now commonly “fingerprinted”. When a sample is taken from either a piece of meat or poultry that is contaminated with a dangerous form of bacteria, such as E. coli O157:H7, listeria, or campylobacter, it can be cultured to obtain and identify the bacterial isolate. If a person consumes some of the contaminated meat or poultry, and becomes infected as a result, a stool sample can then be cultured to obtain and identify the bacterial isolate. These bacterial isolates are then broken down into their various component parts creating a DNA “fingerprint”. The “fingerprint” of the bacteria can then be compared and matched up to the “fingerprint” of isolates from persons who consumed the contaminated product. When DNA “fingerprints” match, it, along with solid epidemiological work, is proof that the contaminated product was the source of the illness.
The process of obtaining the DNA “fingerprint” is called Pulse Field Gel Electrophoresis, or PFGE. This technique is used to separate the DNA of the bacterial isolate into its component parts. It operates by causing alternating electric fields to run the DNA through a flat gel matrix of agarose, a polysaccharide obtained from agar. The pattern of bands of the DNA fragments – or “fingerprints” – in the gel after exposure to the electrical current is unique for each strain and sub-type of bacteria. By performing this procedure, scientists can identify hundreds of strains of E. coli O157:H7 as well as strains of listeria and campylobacter.
