Table 2.

Surgical site infections, infection depth, bacteria type and treatments by pre-intervention and intervention group

Variable	Pre-intervention group (n = 375)	Intervention group (n = 205)	P value
SSI, intention to treat, n (%)	50 (13.3)	11 (5.4)	< 0.01
SSI per protocol, n (%)	48 (14.5)	11 (5.3)	< 0.01
Reoperation due to SSI n, (%)	31 (8.3)	6 (2.9)	0.02
Type of reoperation, n (%)
Skin wound revision	4 (1.1)	2 (1.0)	0.99
Bone flap removal	7 (1.9)	1 (0.5)	0.27
Intradural operation	20 (5.3)	4 (2.0)	0.05
Depth of SSI, n (%)
Superficial	20 (5.3)	4 (2.0)	0.05
Deep	3 (0.8)	1 (0.5)	0.99
Organ/space	27 (7.2)	6 (2.9)	0.04
Use of additional iv antibiotics, days/100 operations	160	74	0.07
Use of additional po antibiotics, days/100 operations	445	114	< 0.01
Total use of additional antibiotics (IV + PO), days/100 operations	605	188	0.03
Additional outpatient visits, visits/100 operations	33	10	< 0.01
Bacteria type, n (%)a
Staphylococcus aureus	10 (2.7)	3 (1.5)	0.56
Coagulase-negative staphylococci	3 (0.8)	2 (1.0)	0.99
Proprionebacterium acnes	22 (5.9)	4 (2.0)	0.04
Other species	8 (1.8)	2 (1.0)	0.51
Negative culture	12 (3.2)	1 (0.5)	0.43

^aA total of 6 patients had cultures with more than bacteria type identified