The aim of this study was to evaluate the bacteriological contamination (thermo-tolerant coliform, TC) of fresh Oreochromis niloticus marketed in Sobral City (Ceará, Brazil). A total of 40 samples (skin=20 and muscle=20) obtained in 2015 were analyzed. The results indicated that 18 samples (90%) showed the same TC contamination index in the skin and muscle, and in two samples (10%), a significant difference was observed between the TC MPN of the skin and the muscle. In sample 5, TC MPN g-1 of 3 and 15 were detected in the skin and muscle, respectively, and in sample 6, TC MPN g-1 of 3.6 and 9.2 were observed in the skin and muscle, respectively. Escherichia coli strains resistant to tetracycline (n=2) and meropenem (n=1) were detected in muscle, and that resistant to chloramphenicol + tetracycline (n=1) was observed in skin. The results indicate that O. niloticus may be a source of transmission of enteric bacteria resistant to antibiotics, to humans.

Keywords: Enterobacteria, Oreochromis niloticus, resistance to drugs, most probable number (MPN).