Tetracycline Resistant Genes as Bioindicators of Water Pollution

Abstract

The current study aimed to investigate the prevalence of tetracycline resistant bacteria isolated from different water samples and the genes responsible for this resistance. Two hundred fifty isolates were isolated from different water samples from two different locations. Isolates were obtained from El-Zamalek site was (n =110) and from Rod El-Farag site was (n = 140). A hundred isolates out of 250 bacterial isolates (40%) were resistant to tetracycline at a concentration of 16 μg/ml. Only 31 (31%) were selected due to their resistance to (32 μg/ml) tetracycline for identification. All selected isolates were identified according to biochemical and the 16S sequence techniques. The 16S rDNA gene sequences of the bacterial isolates which were reported in this study were submitted to the NCBI database. Of the 31 isolates were analyzed by Polymerase Chain Reaction (PCR), results showed that 41.9 % (13/31) harbored tet A gene, 74.2% (23/31) carried tet D gene, while 12.9 % (4/31) carried tet M gene. Whereas tet B, tet C and tet O were not detected. Twenty-one isolates (67.7%) harbored a single tet gene, five isolates (16.1%) harbored two different tet genes while three isolates (9.7 %) harbored three different tet genes. Moreover, two isolates were free from any tested tet genes.