1. Bioscience Research Institute, Ibn-Sina University, Aljerif West, Khartoum, Sudan
2. Microbiology Department, College of Medicine, Al-Qassim University, Al-Mulida, Saudi Arabia
3. Microbiology Department, College of Medicine, Alribat University Hospital, Khartoum, Sudan
4. Department of Global Health and Infection, Brighton and Sussex Medical School, Brighton BN1 9PX, UK