• Demonstrator in Microbiology Department Faculty of Science, Ain Shams University, Cairo, Egypt since November 14th1991 till April 11th 2002 • Research Fellow in Ain Shams University, Bacteriology research unit Faculty of Science, Ain Shams University, Cairo, Egypt since 1993 till 2009 • Assistant lecturer of Microbiology Faculty of Science, Ain Shams University, Cairo, Egypt since May 20th 2002 till August 26th 2009 • Research Assistant in Bacteriology, Faculty of Science, Ain Shams University, Cairo, Egypt since 1993 till 2012 • Lecturer of Bacteriology Faculty of Science, Ain Shams University, Cairo, Egypt since August 26th 2009 till now Assistant Professor of Microbiology, Tabuk University, Faculty of Science, Biology Department , Tabuk , Saudi Arabia since 27th 2013 til now Associate Professor of Microbiology, Ain Shams University, Cairo, Egypt since August 26th 2021 till now