Antibiogram of Putative Bacterial Pathogens Isolated from Some Water Bodies in Rivers State, Nigeria

Exponential increase in the fouling of surface water bodies through discharge of untreated domestic and industrial effluents and direct defecation is posing a big treat to surface water quality. This study was aimed at determining the population of pathogenic bacteria in the selected surface water during dry and wet seasons with a view to determine their level of antimicrobial resistance and susceptibility. Water samples were collected from three tributes of the New Calabar River along Ogbogoro, Rumuolumeni and Mgbuodohia which are located in the Niger Delta region of southern Nigeria. The samples were collected during dry and wet season. The sampling locations for each of the tributaries were near dredging site, near human waste disposal site and 300 meters away from the river bank destinated as general point. Bacteria isolation was carried out using standard spread plate method. Isolates were identified based on the morphology, biochemical/molecular characterization of the isolates. The isolates were subjected to antimicrobial testing using the disk diffusion method. Bacterial isolates from the three tributes were identified to belong to the following genera: Citrobacter, Enterobacter, Bacillus, Vibrio, Klebsilla, Pseudomonas, Proteus, Staphylococcus, Shigella, Salmonella, Serratia, Chromobacterium and Escherichia coli. E.coli had the highest occurrence in the three water sources followed by Staphylococcus aureus. Antimicrobial susceptibility test for E.coli, Salmonella, Shigella and Vibrio cholera isolates was performed using twelve commonly prescribed antibiotics: Amoxicilin Clavulanete (30µg), Cefotaxine (25µg), Imipenem/Cilastatin (10/10µg), Ofloxacin (5µg), Gentamycin (10µg), Nalidixic Acid (30µg), Ampiclox (10µg), Cefexime (5µg), Levofloxacin (5µg), Nitrofurantoin (300µg), Cefuroxime (30µg) and Ceftriaxone Sulbactam (45µg). The antibiogram showed 100% susceptibility of all the tested isolates from the three water bodies to Ofloxacin and Levofloxacin. E.coli isolates recorded 100% resistance to Cefuroxime, Cefotaxime, Nitrofurantoin and Ampicolx. Salmonella isolates recorded 100% resistance to Augmentin and Ampiclox. Shigella isolates recorded 100% resistance to Augmentin, Nitrofurantoin and Ampiclox. Vibrio cholerae isolates recorded 100% resistance to Cefotaxime, Nalidixic acid and Nitrofurantoin. The result showed that susceptibility of the bacterial isolates tested was generally less for the older and more widely used antibiotics. It is concluded that Ofloxacin and Levofloxacin can be the antibiotics of choice in the treatment of infections caused by these bacteria.