G(+) (n = 11)

G(−) (n = 12)

Lap-gastrointestinal

4

1

Open gastrointestinal

1

2

Hepatectomy

0

1

Lap-gynecological

1

1

Open gynecological

0

1

Craniotomy

2

1

Cervical

1

3

Laminectomy

1

0

Nephrectomy

1

1

Thymectomy

0

1