1. HIV/AIDS & Global Health Research Programme, Department of Microbiology, University of Venda, Thohoyandou 0950, South Africa
2. Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea, Cameroon
3. Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Fort Hare, Alice 5700, South Africa