- Email: [email protected]
Far more than 7 billion
Correspondence
Non-O157 Shiga-toxinproducing Escherichia coli The recent outbreak of a non-O157 Shiga-toxin-producing Escherichia coli (STEC) did not surprise me.1 In 2007,2 I noted the widespread nature of non-O157 STEC: most ruminants carry them in their intestinal flora, and improved methods of isolation suggest that the serotype could be present in almost all ruminants; whereas O157 STEC are the minority, if found at all. O157 isolates are rare when all STEC are sought rather than a single serotype (by use of a O157-specific medium). The absurdity of the use of special media that detect the O157 clone only was shown in 1996 during an investigation of an outbreak of mainly STEC O111, but also other serotypes, such as O157.3 The degree of clinical severity of the patients’ condition was proportional to the number of different STEC serotypes to which they were exposed, rather than a particular STEC serotype. Many laboratories do not seem to take into account the diversity of E coli serotypes in the gastrointestinal tract of a human being at any one time.4 A similar situation exists with regard to laboratory investigations in animals.
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The full investigation of outbreaks is essential to understand their causes. In the Comment5 about the German O104 outbreak, Hugh Pennington notes that four of nine outbreaks of intestinal infections linked to bean sprouts were caused by E coli O157. These bean sprouts could have been contaminated with animal faecal matter, and other STEC serotypes might have been involved. The development of a medium that will select for all STEC rather than specifically for one or a few could help our understanding of human infection and is needed urgently. An organisation such as the European Centre for Disease Prevention and Control should initiate such an endeavour. I declare that I have no conflicts of interest.
Karl A Bettelheim [email protected] Rosedale Lodge, London N14 4PH, UK 1
2
3
Bielaszewska M, Mellmann A, Zhang W, et al. Characterisation of the Escherichia coli strain associated with an outbreak of haemolytic uraemic syndrome in Germany, 2011: a microbiological study. Lancet Infect Dis 2011; 11: 671–76. Bettelheim KA. The non-O157 shiga-toxigenic (verocytotoxigenic) Escherichia coli; under-rated pathogens. Crit Rev in Microbiol 2007; 33: 67–87. Goldwater PN, Bettelheim KA. An outbreak of hemolytic uremic syndrome due to Escherichia coli O157:H7: or was it? Emerg Infect Dis 1996; 2: 153–54.
4
5
Bettelheim KA, Faiers M, Shooter RA. Serotypes of Escherichia coli in normal stools. Lancet 1972; 300: 1224–26. Pennington H. Escherichia coli O104, Germany 2011. Lancet Infect Dis 2011; 11: 652–53.
Far more than 7 billion The third sentence of the Editorial1 in the November issue of The Lancet Infectious Diseases—“That planet Earth now supports more people than have lived in all of human history is cause for reflection on how we got here, and what might be done to produce a stable population with an acceptable quality of life”—is not correct. In fact, although the 7 billion people alive today are indeed more than have lived at any one time, an estimated 83 billion people have lived in all of human history.2 I declare that I have no conflicts of interest.
Jon E Rohde [email protected] School of Public Health, University of the Western Cape, Cape Town, South Africa 1 2
The Lancet Infectious Diseases. 7 billion of us. Lancet Infect Dis 2011; 11: 801. BBC News. The world at 7 billion. Oct 27, 2011. http://www.bbc.co.uk/news/world-15391515 (accessed Oct 27, 2011).
www.thelancet.com/infection Vol 12 January 2012
Non-O157 Shiga-toxinproducing Escherichia coli The recent outbreak of a non-O157 Shiga-toxin-producing Escherichia coli (STEC) did not surprise me.1 In 2007,2 I noted the widespread nature of non-O157 STEC: most ruminants carry them in their intestinal flora, and improved methods of isolation suggest that the serotype could be present in almost all ruminants; whereas O157 STEC are the minority, if found at all. O157 isolates are rare when all STEC are sought rather than a single serotype (by use of a O157-specific medium). The absurdity of the use of special media that detect the O157 clone only was shown in 1996 during an investigation of an outbreak of mainly STEC O111, but also other serotypes, such as O157.3 The degree of clinical severity of the patients’ condition was proportional to the number of different STEC serotypes to which they were exposed, rather than a particular STEC serotype. Many laboratories do not seem to take into account the diversity of E coli serotypes in the gastrointestinal tract of a human being at any one time.4 A similar situation exists with regard to laboratory investigations in animals.
12
The full investigation of outbreaks is essential to understand their causes. In the Comment5 about the German O104 outbreak, Hugh Pennington notes that four of nine outbreaks of intestinal infections linked to bean sprouts were caused by E coli O157. These bean sprouts could have been contaminated with animal faecal matter, and other STEC serotypes might have been involved. The development of a medium that will select for all STEC rather than specifically for one or a few could help our understanding of human infection and is needed urgently. An organisation such as the European Centre for Disease Prevention and Control should initiate such an endeavour. I declare that I have no conflicts of interest.
Karl A Bettelheim [email protected] Rosedale Lodge, London N14 4PH, UK 1
2
3
Bielaszewska M, Mellmann A, Zhang W, et al. Characterisation of the Escherichia coli strain associated with an outbreak of haemolytic uraemic syndrome in Germany, 2011: a microbiological study. Lancet Infect Dis 2011; 11: 671–76. Bettelheim KA. The non-O157 shiga-toxigenic (verocytotoxigenic) Escherichia coli; under-rated pathogens. Crit Rev in Microbiol 2007; 33: 67–87. Goldwater PN, Bettelheim KA. An outbreak of hemolytic uremic syndrome due to Escherichia coli O157:H7: or was it? Emerg Infect Dis 1996; 2: 153–54.
4
5
Bettelheim KA, Faiers M, Shooter RA. Serotypes of Escherichia coli in normal stools. Lancet 1972; 300: 1224–26. Pennington H. Escherichia coli O104, Germany 2011. Lancet Infect Dis 2011; 11: 652–53.
Far more than 7 billion The third sentence of the Editorial1 in the November issue of The Lancet Infectious Diseases—“That planet Earth now supports more people than have lived in all of human history is cause for reflection on how we got here, and what might be done to produce a stable population with an acceptable quality of life”—is not correct. In fact, although the 7 billion people alive today are indeed more than have lived at any one time, an estimated 83 billion people have lived in all of human history.2 I declare that I have no conflicts of interest.
Jon E Rohde [email protected] School of Public Health, University of the Western Cape, Cape Town, South Africa 1 2
The Lancet Infectious Diseases. 7 billion of us. Lancet Infect Dis 2011; 11: 801. BBC News. The world at 7 billion. Oct 27, 2011. http://www.bbc.co.uk/news/world-15391515 (accessed Oct 27, 2011).
www.thelancet.com/infection Vol 12 January 2012