ABSTRACT
Disposal of untreated abattoir effluent into natural water bodies pose serious public health concern. Therefore, monitoring of the bacteriological quality of polluted water bodies is of utmost importance. This study investigated occurrence and antibiogram of Vibrio strains of public health significance associated with abattoir effluents discharged into the Ikpoba river, Benin City, Nigeria. Test samples were collected weekly for 6 weeks from four (4) sites: point source (PS), confluent point (CP), 500 m upstream (US) and 500 m downstream (DS) from point of CP contact with the Ikpoba river respectively. The physico-chemical (pH, temperature, turbidity, sulphate, nitrate, phosphate, BOD, TSS, and TDS) and microbiological qualities of the test samples were determined using standard methods. Isolates were identified using standard microbiological and molecular techniques. The antibiotic susceptibility profile of selected Vibrio isolates were also determined and interpreted according to the description of Clinical Laboratory Standard Institute (CLSI). pH ranged between 5.61 and 7.03, while temperature varied from 22°C to 30°C. The highest values for turbidity was >4000 NTU, while the lowest was <20.0 NTU. Sulphate concentration varied between 0.047±0.001 mg/L and 57.59±0.67 mg/L; whereas nitrate concentration ranged from 0.026±0.002 mg/L to 21.74±0.042 mg/L. Phosphate content varied between 0.015±0.001 mg/L and 3.23 ±0.002 mg/L; while BOD, TSS, and TDS had the following values: 1.03±0.01mg/L to 35.37±0.27 mg/L; 250.00±0.1 mg/L to 10500.00±0.15 mg/L; and 10.00±1.00 mg/L to 10300.00±0.1 mg/L respectively. Total bacterial count ranged from 7.1×103±283 cfu/mL to 1.95×106±0.48 cfu/mL; while mean E. coli counts varied between 0±0 and 4.9×105±0.49 cfu/mL. Coliform counts ranged from 2.9×104±0.14 cfu/mL to 1.2×106±0.28 cfu/mL); whereas Vibrio population density varied between 0±0 and 1.51×106±0.7 cfu/mL. Of the fifty (50) presumptive Vibrio isolates, 9(18%) were confirmed as Vibrio spp.; 2 (22.2%) as V. Vulnificus and 3(33.3%) as V. paraheamolyticus using PCR techniques. The Vibrio isolates were sensitive to ceftazidime (56%), ceftriaxone (54%) and ofloxacin (42%); and resistant to oxacillin (96%), vancomycin (90%), amoxicillin (70%) and tetracycline (40%). The current study demonstrated that abattoir effluents were important reservoirs of multidrug resistant Vibrio spp. of public health significance, and could be a source of Vibrio disease outbreak in Benin City, Nigeria if not given appropriate attention by relevant stakeholders.
