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[SANET-MG] E coli 0157 and its transducing viruses that transduce virotoxin in polluted water
The ready transmission of E coli 0157 and the transducing viruses that
spread toxin gene appear in polluted waters in EU as well as in USA.Our
experience in Ontario was that water pollution leads to deadly outbreaks
in cities. Irrigations systems may as well spread the bacteria and its
viruses to vegetables and fruits.
Gesundheitswesen. 2005 Dec;67(12):858-61. Links
[Risk factors for abundance of shiga toxin producing Escherichia coli in
sewage water][Article in German]
Burckhardt F, Heissenhuber A, Morlock G, Busch U, Schindler P, Fruth A,
Ammon A, Wildner M.
Bayerisches Landesamt fur Gesundheit und Lebensmittelsicherheit,
Shiga toxin producing Escherichia coli (STEC) in sewage influent into
surface water are a potential source of human infections with STEC.
Eight sewage treatment plants in Bavaria, Germany, were sampled at
regular intervals from 2003 to 2004 in order to estimate STEC load and
quantify risk factors. 95 of 378 samples (25 %) were tested positive for
stx1and/or stx2 with PCR after enrichment culture. STEC elimination
after treatment was 44 %. The following risk factors were analysed with
logistic regression: location of sewage plant (rural vs. urban),
treatment plant technology (two stage vs. three stage treatment) and
sampling location (sewage input vs. sewage output). Rural plants had
odds-ratios of 1,7 (95 % CI 1.03 - 2.69; p = 0.038) for a positive stx1
and/ or stx2 PCR result, sampling at sewage input of 2.1 (95 %CI 1.28 -
3.36; p = 0.003) and three stage plants of 1.51 (95 % CI 0.94 - 2.44; p
= 0.087, not significant). Sampling after rain and after dry spells had
no impact on STEC abundance (univariate Chi-square test = 0.01; df1; p =
0.920). Rural sewage plants had higher odds of STEC content. The
influence of the sewage plant technology on the STEC load requires
Letters in Applied Microbiology
Volume 42 Page 48 - January 2006
Volume 42 Issue 1
Detection of phages carrying the Shiga toxin 1 and 2 genes in waste
water and river water samples
R. Dumke1, U. Schröter-Bobsin1, E. Jacobs1 and I. Röske2
Aims: To evaluate the occurrence and abundance of phages that carry the
stx1 and stx2 gene in water samples of different quality.
Methods and Results: Phages growing on the Shiga toxin-negative
Escherichia coli O157:H7 (ATCC 43888) strain were enumerated by a plaque
assay in concentrated raw and treated waste water samples and river
water samples. Plaques were investigated for the presence of stx1 and
stx2 genes by a multiplex/nested PCR procedure. An overall number of 805
plaques were tested for the presence of stx-carrying phages. Stx genes
could be demonstrated in 2% (stx1) and 16% (stx2) of the plaques.
Stx-phages were eliminated with approximately the same efficiency in
comparison with somatic coliphages during the waste water treatment process.
Conclusions: Due to the low numbers of phages carrying the stx genes 1
and 2 in treated waste water and river water, the dilution and
inactivation of host bacteria and the unsuitable conditions for the
transduction of host organisms in aquatic environments, it is difficult
to derive from the data the direct evidence for a public health problem.
Significance and Impact of the Study: The results show the quantitative
occurrence of stx-carrying phages in waste and river water and confirm
the frequent circulation of these viruses in the aquatic environment.
FEMS Microbiology Letters
Volume 258 Page 127 - May 2006
Volume 258 Issue 1
Newly identified bacteriophages carrying the stx2g Shiga toxin gene
isolated from Escherichia coli strains in polluted waters
Cristina García-Aljaro, Maite Muniesa, Juan Jofre & Anicet R. Blanch
Shiga toxin-converting bacteriophages are the main vehicle involved in
horizontal transmission of stx1 and stx2 genes, which has led to the
current spread of stx genes among a high number of Escherichia coli
serotypes and other enterobacteria. Several stx gene variants have been
described, although some of the variants have never been isolated from
inducible bacteriophages. In this study, two stx2g-carrying
bacteriophages induced from two different E. coli O2:H25 strains
isolated from different wastewater samples were characterized. These
bacteriophages when transduced into Shigella sonnei retained their
ability to produce Stx2 protein. They had similar but not identical DNA
restriction patterns, and similar host ranges. Electron microscopy
studies showed that they had isometric capsids with short tails, which
resembled phage 933W. However, DNA cross-hybridization studies showed
that phage 933W was not closely related to stx2g bacteriophages. This
first description of stx2g-carrying bacteriophages enlarges the list of
stx-carrying bacteriophages involved in horizontal transmission of stx
genes in the environm
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