Physico-chemical and Bacteriological Quality of an Abattoir Wastewater Discharged into Water Bodies in Ibadan, Nigeria and drug resistant profile of isolated Salmonella species

Abstract

The discharge of untreated abattoir wastewater constitutes public health concern because diseases are transmitted through contaminated water bodies. Contaminated water supply systems used for drinking and other purposes have been implicated in the transmission of antibiotic resistant pathogens. This study was carried out to determine the physico-chemical, bacteriological qualities of abattoir wastewater in Ibadan and antibiotics resistance patterns of Salmonella species from the wastewater. Wastewater samples were collected from the slaughter slab and drainage. Physico-chemical parameters, total bacteria counts (TBC) and total coliform counts (TCC) were determined using standard procedures. Salmonella species were isolated from the samples using pour plate techniques and identified using biochemical tests, while susceptibility test of the isolates against 10 antibiotics was determined using disc diffusion technique. The physico-chemical parameters of the wastewater showed total dissolved solids of 4,150 mg/l and 2300 mg/l for slaughter slab and drainage respectively while biochemical oxygen demand was 867.2 mg/l and 698.5 mg/l. Dissolved oxygen was between 0.01 mg/l and 0.02 mg/l; the mean value of TBC and TCC ranged between 4.24x 107- 4.78x107 cfu/ml and 3.03x107-3.51x107cfu/ml respectively. Salmonella species isolated were 48 and were all resistant to ampicillin and ceftriazone. The strains of S. enterica subspecies enterica exhibited resistance to eight antibiotics combination (AMP-TET-OFX-AMC-CLX-CRO-STR-SXT, AMP-TET-AMC-CLX-CRO-CHL-STR-SXT) while two of the isolates were pan-resistant. The abattoir wastewater must be properly treated before being discharged into the environment as it is evident that it harbours multiple antibiotic resistant pathogens.