Page 7 - Molecular Pathogens

Molecular Pathogens (online), 2011, Vol. 2
ISSN 1925-1998 http://mp.sophiapublisher.com
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potassium permanganate and other disinfection
reagents to sanitize the lake of Haikoudonghu, which
may be causing the Salmonella carrying rate decrease,
but the specific cause needs further study.
Comparison of two groups by carapace length,
Salmonella carrying rate of red-eared sliders with
small carapace length was higher than that of
red-eared sliders with big carapace length, in which
red-eared sliders with small carapace length from
Nandujiang carried highest rate of Salmonella that
was consistent with the findings of Keymer (1972).
Amphibians and reptiles carrying Salmonella usually
without any symptoms (Anonymous, 1999). Mitchell
(1980) and other studies have shown that S. Urbana, S.
Lichfield, and S. Java were the most human infection
serotypes caused by turtles in the Salmonella ,
especially affecting infants and young children. Other
serotypes can also be detected from humans (Geue
and Loschner, 2002). This study detected the S.
Lichfield, which indicated the invasive red-eared
sliders in china might cause potential harm to humans.
Detected S. Stanley also is a common pathogens
causing human food poison. In this study, we might
have a preliminary suggestion that the invasive alien
red-eared sliders carrying some Salmonella serotypes
closely to human health, which may have a direct
impact on human health (OIsen et al., 2001).
In China, red-eared sliders, albeit an exotic invasive
species, but is still widely used as food turtle and pet
turtle. Obviously, the red-eared sliders, as one of the
main disseminators of Salmonella in reptiles, have
entered the human food chains and ecosystem, human
health and the environment posed by the potential
risks and dangers.
3 Materials and Methods
3.1 Experimental samples collected
We collected 68 of wild red-eared sliders in the two
major rivers of Hainan Island, Nandujiang and
Wanquanhe, and in the downtown lake of Haikou city,
Haikoudonghu during the period between February to
September in 2010, of which Nandu were 26,
Wanquan were 34, and Haikoudonghu were 8. In this
study we have collected wild red-eared sliders divided
into three groups, Nandu was as first group, Wanquan
as second group, Haikoudonghu as third group.
Meanwhile each group was sub-divided as subgroups,
the carapace length of a red-eared sliders less than
4-inch divided into group A, greater than or equal to 4
inches into the B group. 26 samples from Nandu (First
Group) were gone into Group A of 4 red-eared sliders
and Group B of 22 red-eared sliders. 34 samples from
Wanquan (Second Group) were gone into Group A of
9 red-eared sliders and Group B of 25 red-eared
sliders. 8 red-eared sliders from Haikoudonghu were
grouped into 7 of Group A and 1 of group B.
3.2 Standard strains of Salmonella
In this study, Salmonella typhimurium was used as the
standard strains, the standard accession number of the
Salmonella typhimurium is CMCC (B) 50071, come
from the National Institute for the Control of
Pharmaceutical and Biological Products (NICPBP).
3.3 Bacterium culture medium
Nutrient broth, Salmonella chromogenic Medium,
vassiliadis enrichment broth, and Salmonella
biochemical identification kit, provided by HuanKai
Biotechnology Co., Ltd. Guangdong; Salmonella
diagnostic serum (60 reactions) were purchased from
Lanzhou Institute of Biological Products; Salmonella
diagnostic serum for 0A-I, purchased from S & A
company in Thailand.
3.4 Method for Salmonella Identification
Salmonella bacteria were identified by following the
procedures of GB 4789.4-2010 established as the
Chinese National Standard Food Safety Inspection.
3.4.1 Sampling and enrichment
Bacterium samples were collected with a steriled
cotton swab in red-eared sliders cloaca, then add 1 mL
nutrient broth, cultured 6~8 h at 37 ; then took 60 μL℃
medium transferring into 1mL magnesium chloride
malachite green, cultured 16~18 h at 37℃ .
3.4.2 Bacterial isolation of Salmonella
Took one loop of Salmonella cultured medium with
the inoculation loop to inoculate by crossing the plate
of Salmonella chromogenic medium and incubated
16~18 h at 37℃ . If there is purple colonies appeared,
the isolate will be considered as tentative Salmonella
bacterium. Pick three purple single colonies ready for