Thesis (M.Sc.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

Methicillin-resistant Staphylococcus aureus (MRSA) is characterized by its resistance to almost all beta lactams and other antibiotics belonging to various classes. The ability of MRSA to spread in hospitals, particularly in intensive care units (ICUs) has posed a major challenge for infection control worldwide. Based on their localization in the human body, hospital-acquired MRSA (HA-MRSA) can be classified into colonized or infectious. The aim of this work is to conduct an analysis to differentiate between these two classes. From a total of 100 isolates collected from the ICU of two major Egyptian hospitals, 49 isolates were confirmed as MRSA, out of which, 30 isolates were infectious and 19 were colonized. Biofilm formation showed that infectious isolates had significantly higher biofilm formation ability. The antibiogram revealed that each type of isolates had its own resistance pattern; MIC of a number of infectious isolates showed an MIC creep which can lead to future resistance. 16SrRNA sequencing confirmed the identity of several isolates; ERIC PCR typing classified the isolates into several groups. Multi locus sequence typing confirmed the relation between the isolates obtained from ERIC typing and showed the origin of some of the isolates. The resistance gene mecA was absent in one of the colonized isolates

Issued also as CD