Occurrence of tetracycline resistant bacteria and resistance gene (fetW) in hospital and municipal wastewaters

The occurrence and spread of antibiotic resistant bacteria
(ARB) and genes in the environment is a public
health concern. Wastewater is a potential source for dissemination
of ARB and antibiotic resistance genes
(ARGs) in the environment. The present study was conducted
to determine the abundance of tetracycline resistant
bacteria (TCr) and gene (tetW) in hospital and municipal
wastewaters. The influence of wastewater treatment
plants (WWTPs) on the fate of TCr bacteria and
tet(W) gene was also investigated. A total of 66 samples
from raw and final effluent of hospital and domestic
WWTPs were analyzed. TCr bacteria as a major part of
the heterotrophic plate count (HPC) bacteria were found
in the raw wastewater and final effluent samples in a
concentration ranged from 1.28×108- 5.19×106 to
4.60×106 - ND (not detected) CFU/ 100ml, respectively.
Tet(W) gene concentration in the raw wastewaters
were found to be in the range of 3.87×107-6.23×1013
copies/100ml and WWTPs did not contribute in effective
reduction of tet(w) gene. No significant correlation was
found between the levels of tet(W) gene and TCr bacteria
in either raw wastewater or final effluent. The results of
this study showed that TCr bacteria and tet(W) gene were
present in relatively high levels in both municipal and
hospital wastewaters. The results also indicated that conventional
wastewater treatment plants didn’t contribute in
effective reduction of tet(w) gene and wastewater effluents
are a potential source for dissemination of tet(w)
gene into the natural environment.