Table 2.

Frequencies of SSI^§ according to type of intervention and NNIS^§§ index category.

Surgical procedure*	Total** number of procedures (n = 4,386)	N SSI (%)	N SSI (%) according to NNIS index category
			M	0	1	2 + 3
Breast surgery	406	13 (3.2%)	-	10/281 (3.5%)	2/111 (1.8%)	1/10 (10%)
Cesarean section	1012	27 (2.6%)	-	20/775 (2.6%)	6/218 (2.7%)	0/8 (0%)
Cholecistectomy	740	30 (4%)	4/287 (1.4%)	11/236 (4.6%)	9/145 (6.2%)	4/59 (6.7%)
Gastric surgery	147	20 (13.6%)	1/3 (33.3%)	3/50 (6%)	1/63 (1.6%)	4/23 (17.4%)
Appendectomy	221	19 (8.6%)	0/16 (0%)	1/108 (0.9%)	13/76 (17.1%)	3/18 (16.6%)
Colon surgery	338	64 (18.9%)	2/4 (50%)	14/70 (20%)	24/151 (15.9%)	22/109 (20.2%)
Hernia repair	1014	41 (4%)	1/19 (5.3%)	20/641 (3.1%)	15/283 (5.3%)	4/46 (8.7%)
Abdominal hysterectomy	346	21 (6.1%)	1/12 (8.3%)	7/217 (3.2%)	11/91 (12.1%)	1/20 (5%)
Vaginal hysterectomy	162	6 (3.7%)	-	3/117 (2.5%)	3/41 (7.3%)	0/2 (0%)

^§ Surgical site infections.

^§§National Nosocomial Infection Surveillance index category.

*Cardiovascular and other minor interventions are not reported because the denominator was too little (n = 21) to be included in statistical analysis.

** The procedures with no postdischarge surveillance (258) were not included.

M: no risk factor for NNIS index score plus laparoscopical procedure (NNIS = -1).