Journal of Pure and Applied MicrobiologyVol. 6 No. 4

Assessment of Listeria Bacteria Abundance and Physicochemical Quality of the Effluents of a Typical Semi-urban Wastewater Treatment in South Africa

A.I. Okoh*, Z.N. Cwala, N.P. Ngqwala, E.O. Igbinosa, E.O. Odjadjare and O.O. Okoh

Applied and Environmental Microbiology Research Group, (AEMREG) Department of Biochemistry and Microbiology, University of Fort Hare Private Bag X1314, Alice 5700, South Africa.

Received on 01 July 2012 and accepted on 10 August 2012



The present study was undertaken to assess the efficiency of a typical semi-urban wastewater treatment plant in Eastern Cape Province of South Africa for the removal of Listeria pathogens in wastewater. The abundance of Listeria pathogens in the final effluent as well as their in vitro antibiogram characteristics was evaluated. Total Listeria counts ranged from 9.0 ? 103 to 3.40 ? 105 cfu/ml; 7.60 ? 103 to 8.10 ? 104 cfu/ml and 2.0 ? 101 to 3.5 ? 104 cfu/ml for mixed liquor, pre-chlorinated and final effluents respectively. The final effluents did not meet the standards limits for turbidity, EC, TDS, DO, COD, PO4 and Listeria abundance, but fell within recommended limits for pH, temperature and salinity after treatment. Listeria strains showed resistance to at least one antibiotic, multiple antibiotic resistances ranging from 2 to 7 antibiotics. The study showed that treated final effluents in South Africa could be an important source of resistant Listeria pathogens in the environment.

Keywords : Wastewater effluent, Listeria pathogens, Antibiogram, physicochemical qualities.