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found to be present on transposon Tn552 on both chromosomes, together with the sensory and regu-latory genes blaR and blaI, respectively25), although blaZ, blaR and blaI genes are found on plasmids in many other S. aureus strains26). The IDSA1 and TW20 strains also shared Tn5801-like elements with the tetM (tetracycline-resistant determinant) and dfrG (trimethoprim-resistant determinant) genes27, 28), Tn554 with tetM (etracycline-resistant determinant)27) and ant(9)-Ia (aminoglycoside- resistant determinant), φSPb-like prophages with aac(6’)-aph(2”) and aph(3’)-III (aminoglycoside- resistant determinants) and Type-III SCCmecs with mecA (penicillin-binding protein with lower affinity to b-lactams, conferring bacterial resis-tance to these reagents)21).Although the IDSA1 and TW20 strains had the same ST, other mobile genetic elements differed in IDSA1 and TW20. For example, IDSA1 possessed, two prophages φNM229) and φSa224), which were absent from TW20. These two prophages did not encode any known drug-resistance or virulence-re-lated genes. In contrast, IDSA1 lacked the νSa1 element30, 31), which frequently carries genes that encode enterotoxins K and Q. IDSA1 also lacks SCCmercury32), which carries mercury resistance genes, an SCC that tends to be tandemly inserted with SCCmec. Although some positions of trans-posons and insertion sequences were similar in the two chromosomes, others were different. For example, two Tn554 and a pseudo Tn554 (ψTn554) Regions of >90% nucleotide identity are shown with red lines, illuminating gaps representing regions specific to each strain. Positions of mobile genetic elements are indicated as in Figure 2.Figure 3　Genome rearrangement map of Staphylococcus aureus strain IDSA1 compared with S. aureus strain TW20in IDSA1 were found to be inserted into the corre-sponding positions of TW20, whereas TW20 has an extra Tn554 carrying the genes ant(9)-Ia (an aminoglycoside resistant determinant) ermA (a macrolide resistant determinant) adjacent to SCCmercury. The two chromosomes shared eight IS256, however, IDSA1 had eight additional IS256 (data not shown).To our knowledge, this is the first intensive study of the molecular epidemiology of MRSA strains isolated in Indonesia. Whole genome sequences of these MRSA strains, which were isolated from patients in a hospital in Surabaya City, Indonesia, over a one-year period, differed in their genetic backgrounds, suggesting that they had originated from many regions of the world. These strains includeed lineages of ST30 (typically seen in community-acquired MRSA [CA-MRSA] isolated worldwide, except for northern America), ST239 (typically seen in worldwide hospital-acquired MRSA [HA-MRSA]) ST97 (typically seen in Euro-pean livestock-associated MRSA [LA-MRSA]), and ST789 (typically seen in African CA-MRSA)22). Also isolated was ST672, information on which has been very limited to date. These findings suggest that MRSA strains migrate with human movement. Indeed, many Indonesian people go to other coun-tries as migrant laborers, which may result in their acquisition and spread of MRSA strains with various 153Discussion