TABLE 1.

Most common pulsed-field types among MSSA and MRSA isolates from nasal colonization studies

Methicillin statusS. aureus pulsed-field type; no. (%) of isolates in:
2001 to 20022003 to 2004
MethicillinUSA200; 92 (29.1)USA200; 59 (24.9)
    susceptibleaUSA600; 40 (12.7)USA600; 33 (13.9)
USA900; 29 (9.2)USA900; 10 (4.2)
USA800; 21 (6.6)Group A; 10 (4.2)
Group A; 18 (5.7)USA500; 9 (3.8)
USA300; 14 (4.4)Group D; 9 (3.8)
Other types; 102 (32.3)Other types; 107 (45.1)
MethicillinUSA100; 36 (48.0)USA100; 60 (44.8)
    resistantbUSA800; 17 (22.7)USA800; 23 (17.2)
USA700; 7 (9.3)USA300; 23 (17.2)
USA300; 6 (8.0)USA400; 8 (6.0)
USA1000; 2 (2.7)USA200; 6 (4.5)
USA400; 1 (1.3)USA700; 3 (2.2)
Other types; 6 (8)Other types; 11 (8.1)
  • a Every tenth MSSA isolate was characterized. For 2001 to 2002, n = 316; for 2003 to 2004, n = 237.

  • b All MRSA isolates were characterized. For 2001 to 2002, n = 75; for 2003 to 2004, n = 134.