Microbial assessment and prevalence of antibiotic resistance in polluted Oluwa River, Nigeria

Abstract Antibiotics are emerging environmental contaminants, causing both short-term and long-term alterations of natural microbial communities due to their high biological activities. The antibiotic resistance pattern of bacteria from anthropogenic polluted Oluwa River, Nigeria was carried out. Microbial profiling and antibiotic sensitivity tests were carried out on water and sediment samples using 13 different antibiotics. Microorganisms isolated include those in the genera Bacillus , Micrococcus , Pseudomonas , Streptococcus , Proteus and Staphylococcus . The microbial count of isolates from water samples ranged between 94.10 × 10 2  Cfu/100 ml and 156.20 × 10 2  Cfu/100 ml while that of sediment samples ranged from 2.55 × 10 4  Cfu g −1 to 14.30 × 10 4  Cfu g −1 . From the water isolates, 100% resistance to antibiotics was found in Micrococcus spp. and Pseudomonas spp. while another Micrococcus , Streptococcus , Staphylococcus and Bacillus spp. showed between 40% and 90% resistances. From the sediment isolates, 100% resistance to antibiotics was found in a Bacillus spp. and Pseudomonas spp. while another Bacillus , Micrococcus , Staphylococcus , Streptococcus and Proteus spp. showed between 70% and 90% resistances. Multiple antibiotic resistance (MAR) was shown by all the isolates and Bacillus , Micrococcus and Pseudomonas spp. showed the highest resistances (100%) to all antibiotics. Thus, Oluwa River is not safe for public consumption.