33
Tecnología y Ciencias del Agua
, vol. VIII, núm. 3, mayo-junio de 2017, pp. 27-37
Aburto-Medina
et al
.
, Prevalence of
Enterobacteriaceae
and contaminants survey in sediments of the Atoyac River
ISSN 2007-2422
•
Bacterial diversity
in situ
A total of 53 clones were retrieved from the
clone library and they were related to members
of the
Enterobacteriaceae
within the Gammapro-
teobacteria (figure 2). The bacterial diversity of
the surveyed sediments is low; species related
to
Shigella flexneri
,
Escherichia fergusonii
and
E. coli
dominated the clone library. The deg-
radation of hydrocarbons has been reported
recently by
Escherichia fergusonii
(Sriram
et al
.,
2011; Pasumarthi, Chandrasekaran, & Mutnuri,
2013) suggesting the use of some of the detected
compounds by the
Escherichia fergusonii
-related
bacteria, however, these and the other members
of the
Enterobacteriaceae
may also pose potential
health risks to the population.
Shigella flexneri
(B serogroup) is a common cause of bacillary
dysentery in humans. Infection by
Shigella
is
usually via ingestion invading the colonic mu-
cosa and producing an intense inflammatory
reaction leading to tissue destruction (Kotloff
et al
., 1999). Therefore, we tested for the pres-
ence of Shiga genes within our samples but they
were not found. However, future studies would
be necessary to look for further genes encoding
other toxins or virulence and invasion plasmids
(Sansonetti, Kopecko, & Formal, 1982; Ménard,
Sansonetti, & Parsot, 1993; Fagan
et al
., 1999) in
this strain in order to have a proper assessment
of the
Shigella
-related clones pathogenicity.
The high number of clones related to
En-
terobacteriaceae
is not uncommon since the river
receives industrial, agricultural and domestic
effluents; however, our samples were collected
after the wastewater treatment process suggest-
ing the presence of further domestic effluents
or the lack of efficacy during the wastewater
treatment process. This is also constant with
the high levels of coliforms (240 MPN 100 ml
-
1
) found at the same sampling point and with
previous studies (Silva, Muñoz, Isla de Bauer,
& Infante, 2002; Cabrera, Bonilla, Tornero, &
Castro, 2005; Sandoval-Villasana
et al
., 2009).
Table 5. Organic compounds identified by GC-MS from sediments of the Atoyac River sampling position A1.
Quality (%)
Compound
CAS number
91
Undecane
001120-21-4
91
Dodecane
000112-40-3
91
Tridecane
000629-50-5
96
Tetradecane
000629-59-4
90
Hexadecane
000544-76-3
81
Undecane, 2,6-dimethyl-
017301-23-4
93
Dodecane, 2,6,11-trimethyl-
031295-56-4
89
2-Bromo dodecane
013187-99-0
95
Hexadecane, 2,6,10,14-tetramethyl-
000638-36-8
96
Phenol, 2,4-bis(1,1-dimethylethyl)-
000096-76-4
80
4-tert-Butylphenyl acetate
003056-64-2
90
Cyclopenta[g]-2-benzopyran, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-
001222-05-5
98
n-Hexadecanoic acid
000057-10-3
81
Octadecanoic acid
000057-11-4
87
Sulfurous acid, butyl heptadecyl ester
1000309-18-4
91
1,2-Benzenedicarboxylic acid, mono(2-ethylhexyl) ester
004376-20-9
92
1-Eicosene
003452-07-1
90
Cyclotetradecane, 1,7,11-trimethyl-4-(1-methylethyl)-
001786-12-5
87
[Bi-1,4-cyclohexadien-1-yl]-3,3’,6,6’-tetrone, 4,4’-dihydroxy-2,2’,5,5’-tetramethyl-
010493-51-3
91
Cholestan-3-ol, (3.beta, 5.beta.)-
000360-68-9
