Objective: A cross-sectional analytic study of 268 patients who received surgery at Photharam Hospital was conducted to assess the incidence and risk factors of nosocomial surgical site infection (SSI).
Material and Method: The studied patients who voluntarily participated and signed informed consents were interviewed. Pus specimens from SSI patients diagnosed by use of CDC criteria were cultured. After risk factor analysis, the risk screening form was developed and calculated by the Receiving Operating Curve.
Results: The results revealed that incidence of nosocomial SSI was 20.52% (55/268 cases). Of 55 SSI patients, 45.46% were positive for bacterial culture. Risk factors for nosocomial SSI from univariate analysis were (a) age of patients > 60 years, OR = 1.91 (p = 0.043), (b) gender as male, OR = 2.20 (p = 0.024), (c) admitted ward as male surgical ward, OR = 2.42 (p = 0.028), (d) current patients’ illness as diabetes mellitus (DM), OR = 7.92 (p < 0.001) and tuberculosis, OR = 11.88 (p = 0.001), (e) abnormal ASA score, OR = 3.47 (p < 0.001), (f) smoking, OR = 3.72 (p < 0.001), (g) incorrect prophylactic drug use, OR = 2.98 (p = 0.002), (h) duration of admission > 10 days, OR = 4.87 (p < 0.001), and (i) wound dressing > 1 time/day, OR = 4.16 (p < 0.001). After multiple logistic regression analysis, the significant risk factors were (a) current patient’s illness as DM, OR = 14.43 (p = 0.005), (b) smoking, OR = 13.18 (p = 0.001), (c) duration of admission > 10 days, OR = 4.88 (p = 0.032) and (d) wound dressing >1 time/day, OR = 23.32 (p < 0.001). The risk screening form was developed and showed approximately 65% sensitivity and 78% specificity when a cut-off score at risk > 18 was used.
Conclusion: This risk screening form should be considered in other hospitals. When a postoperative patients has a score of 18, they should be considered a potential risk for nosocomial SSI and preventive measures should be integrated to reduce the risk for nosocomial SSI.

Keywords: Nosocomial surgical site infection, Incidence, Risk factors, Risk screening form