Heavy Metals and Antibiotics Susceptibility Profiles of <i>Staphylococcus aureus</i> Isolated from Several Points Receiving Daily Input from the Bodija Abattoir in Ibadan, Oyo State, Nigeria

Abstract

Indiscriminate and unguided discharge of untreated wastewater especially from abattoirs can constitute a public health threat and also stimulate the onset of co-resistance to metal and antibiotics in environmental microorganisms. It has been shown that microorganisms especially bacteria that have the capacity to resist antibiotics and heavy metals, may constitute a public health threat. This study was therefore conducted to determine the susceptibility and tolerance profile of Staphylococcus aureus isolated from abattoir effluent flowing into a receiving river around Bodija market in Ibadan to a range of antibiotics and heavy metals. Ten points were selected for sampling, and the samples were cultured on nutrient agar and mannitol salt agar. A total of 22 Staphylococcus aureus strains were obtained. They were subjected to increasing concentration of six heavy metals [lead (Pb), copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), nickel (Ni)] and five antibiotics. Of the total isolates, 41% were resistant to all the six metals at 1500μg/ml concentration, while the others showed various degree of resistance. A percentage resistance of 22.7% was observed for tetracycline, 100% to ceftazidime, 9.1% to ciprofloxacin and vancomycin while 63.6% of the strains were resistant to oxacillin. All the strains but two showed resistance to all the metals tested, while multiple resistance to antibiotics was also observed. Further studies need to be carried out on the mechanisms of resistance of these strains.