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Re: [SANET-MG] no smoking cow?
Hello John , Lawrence, Brian, Sals and Jeff,
Regarding John's comment on calves with bloody stools. Early on in the
study of E coli 0157 it was found that antibiotic treatment caused the
bacterial cells to lyse (dissolve) releasing vero toxin that damaged
the cells of the gut. Young animals tend to be treated with antibiotics
to enhance growth. Such antibiotics lyse the cells leading to toxin
release and activation of the prophage (virus) carrying toxin genes.
Googling will turn up numerous publications showing that adult cattle
carry E coli 0157 without showing any illness but the fact is so well
established that more publications here seem unnecessary.The
publications below tells how the antibiotics work to make calves sick..
Microbiology (2000), 146, 1085-1090.
Environmental Microbiology
Antibacterials that are used as growth promoters in animal husbandry can
affect the release of Shiga-toxin-2-converting bacteriophages and Shiga
toxin 2 from Escherichia coli strains
Bernd Köhler1, Helge Karch1 and Herbert Schmidt1
Institut für Hygiene und Mikrobiologie der Universität Würzburg,
Josef-Schneider-Str. 2, D-97080 Würzburg, Germany1
Author for correspondence: Herbert Schmidt. Tel: +49 931 201 3905. Fax:
+49 931 201 3445. e-mail: hschmidt@hygiene.uni-wuerzburg.de
Antibiotics are commonly used as growth promoters in animal husbandry
worldwide. This practice has been linked to the emergence of particular
antibiotic-resistant bacteria, and is now controversial. In this study,
the ability of growth-promoting antibiotics to induce Shiga toxin
(Stx)-converting bacteriophages from Stx-producing Escherichia coli
(STEC) strains was investigated. Subinhibitory concentrations of the
antibacterial growth promoters olaquindox, carbadox, tylosin and
monensin were used for induction experiments. The amount of mature
Stx-converting phage particles released from induced and non-induced
cultures was determined, and the production of Stx was simultaneously
measured by ELISA. Whereas the quinoxaline-1,4-dioxide-type antibiotics
olaquindox and carbadox enhanced the release of Stx-converting phage
particles from STEC cells, tylosin and monensin decreased phage
induction. The production of Stx increased or decreased simultaneously
with the amount of free phages. The results of this study show that
particular antibacterial growth promoters can induce Stx phages. In vivo
induction of Stx phages from lysogenic STEC may increase the amount of
free phages in the intestine and therefore may contribute to the spread
of STEC and development of new STEC pathotype
Along with the effect on animals it was found that people infected with
E coli 0157 then treated with antibiotic were far more likely to get
the extreme HUS syndrome because the antibiotic caused the bacteria to
lyse. The studies below give that evidence.
http://www.medscape.com/viewarticle/410077
Escherichia coli Infection: Antibiotics Pose Risk of Hemolytic-Uremic
Syndrome
Antibiotic treatment of children infected with E coli 0157:H7 increases
the risk of hemolytic-uremic syndrome. That, according to results of a
study published in the June 29th issue of the New England Journal of
Medicine.
Researchers conducted a prospective cohort study of 71 children, all
younger than 10 years, who experienced diarrhea linked to E coli
0157:H7. They found that hemolytic-uremic syndrome developed in 5 (56%)
of the 9 children who were administered antibiotics and in only 5 (8%)
of the remaining 62 children.
Several clinical factors were significantly associated with
hemolytic-uremic syndrome: high white blood cell counts on presentation,
evaluation with stool culture soon after onset of illness, and treatment
with antibiotics. The investigators say that the clinical and laboratory
characteristics of the 9 children who received antibiotics and the 62
who did not were similar.
This letter is getting long so I will provide more abstracts on
antibiotic resistance along with the adult cow story in a following
letter. Essentially what was given in this letter was the evidence that
antibiotic may cause problems in people and cows infected with E coli 0157.
sincerely,joe cummins
John D'hondt wrote:
it is clear that healthy cattle frequently have E. coli in their
intestines which does not cause them to have diarrhea or have any
symptoms. E coli kills people but not cows because the human has a
cell surface receptor on the cells of the gut that allow the bacteria
to inject verotoxin into their cells, cows lack such those receptors.
The healthy cattle could pick up E coli 0157 from a visit from the
vet or from a neighbors car or truck.
Hi Joe, I am not so certain that cattle don't suffer from e. coli. At
least many calves sold in Marts here in Ireland die from haemolitic
E.coli infections. This means they die from bloody diarrhea. This
mostly only happens to calves that have been taken away from their
mothers prematurely as most calves are. A calf outside suckling a cow
never gets this disease.
Also, three people died of this E.coli 0157 over a few weeks time. Do
you know how many people in total died in the U.S. during this period?
Or how many sickened for one reason or another? If one looks at the
total picture it should be clear that this "disaster" was blown up out
of all possible proportion. There are many times more people dying
every hour of pesticide poisoning than ever died from this E.coli.
Which does not mean that one should be careless with feed lot slurry
of course.
john
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