The current pollution status of the new Calabar river in the Niger Delta region of Southern Nigeria: A survey of antibiogram profiles of its bacterial isolates

Abstract

The incidence of environmental pollutants on bacterial strains isolated from the New Calabar River in the Niger Delta region of Southern Nigeria were investigated in order to ascertain the possible effects on antibiotic resistance and patterns. The physico-chemical parameters of the water samples assayed included temperature, pH, biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, salinity, chloride, nitrate, phosphate, total dissolved solids, sulphate, oil and grease, cadmium, copper, nickel, lead, mercury and iron. Antibiogram of bacterial isolates from the water samples were sought using the disk diffusion method. Results showed multiple antibiotic resistance patterns among the bacterial isolates. The levels of resistance exhibited by the isolates to specific antibiotics were: Ampicillin 66.7%, Rifampicin 66.7%, Tetracycline 53.3%, Cephalothin 46.7%, Erythromycin 46.7%, Novobiocin 40%, Chloramphenicol 33.3%, Nalidixic acid 33.3%, Streptomycin 33.3%, Cotrimoxazole 26.7%, Norfloxacin 13.3%, Ciprofloxacin 6.7%, Ofloxacin 6.7%, Amikacin 0%, Gentamycin 0% and Pefloxacin 0%. Higher incidence of antibiotic resistance was observed at sites with pronounced industrial and human activities, suggesting possible effect of pollutants on the ecosystem. There was weak correlation (r = 0.28) between incidence of antibiotic resistance and faecal coliforms. This suggests that the antibiotic resistance patterns of these bacterial isolates may be due to factors that are not linked to faecal pollution. The presence of chemical pollutants may have contributed to the increased antibiotic resistance observed at sites with pronounced industrial and human activities.

Key words: Antibiogram, New Calabar river, pollution, coliforms, physico-chemical.