This IS my first power-point presentation, presenting at the Journal Club Harris et al's paper from Science entitled: "Evolution of MRSA During Hospital Transmission and Intercontinental Spread" Many thanks to Dr. Ramy A. for the choice and the fulltext and Dr. Tamer I. for the opportunity, encouragement and great help.

1. Evolution of MRSA During Hospital Transmission and Intercontinental Spread (Harris et al , 2010) Mariam Reyad Rizkallah 5 th year student, Faculty of Pharmacy, Cairo University

5. Why characterization of pathogenic microorganisms? Characterization Local epidemiology: (hospital outbreaks) Same or different strain? Global epidemiology: How geographically-related?

9. Methods Genome-wide analysis, Genomic fingerprinting & DNA comparison 63 isolates 2 samples 1 st Sample 43 isolates Global collection (1982-2003) Intercontinental transmission 2 nd Sample 20 isolates Northeast Thailand (7-month period) Fine-scale transmission

12. Genome Analyzer Applications http :// www . geneworks . com . au / library / MultipleApp_image . jpg

14. Results 6714 SNPs With marked uneven distribution across the genome Core ( 4310) Chromosomal Vertical gene transfer Non-core MGEs Horizontal gene transfer (Major source) 38 homoplasic genes involved in drug resistance “ similar in form & structure, but not in origin”

16. Results – Phylogenetic analysis & geographical relation

18. Source: Pathogen Microevolution in High Resolution. (Aziz et al , 2010, Science Translational Medicine) A map showing the geographical spread of MRSA ST239 as deduced by Harris et al .

23. Results – SNPs analysis from homoplasies in the core regions SNP position Region/gene Isolate SNP (amino acid replaced, syn, intergenic) Antibiotic resistance Nucleotide replaced

24. Results – SNPs analysis from homoplasies in the core regions

26. spa , PFGE vs. phylogenetic analysis

29. Comments & Questions

30. Thank you