Surgical site infection and distribution of pathogens of abdominal contaminated wound: a prospective study

Abstract

Objective To investigate the characteristics of surgical site infection(SSI) and distribution of pathogens of abdominal contaminated wound. Methods The clinical data of 760 patients with digestive tract fistula who were prepared to undergo definitive operation at the Nanjing General Hospital of Nanjing Military Command between November 2011 and November 2013 were prospectively analyzed. Criteria for National Nosocomial Infection Surveillance (NNIS) of Centers for Disease Control and Prevention Definition (CDC) were used to determine SSI. A single-center and prospective observational study was performed in patients who were divided into SSI group and non-SSI group according to postoperative SSI. Demographic information, digestive tract fistula information, duration of hospital stay and SSI-related information were collected and analyzed. Measurement data were presented as M(Qn) and analyzed by the rank-sum test. Results Among 191 cases enrolled in the clinical trial, 51 patients developed SSI with overall incidence of 26.70%, including 36 cases of superficial incisional SSI, 8 cases of deep incisional SSI, and 7 cases of organic/lacunar SSI. SSI occured usually at postoperative week 1. Among the patients in the SSI group, bacteria culture was negative in 5 cases, and positive in 46 cases. There were 71 strains of pathogens separated from SSI group, including 22 strains of Escherichia coli, 14 strains of Enterococcus, 9 strains of Klebsiella pneumonia, 8 strains of Staphylococcus aureus, 7 strains of proteusbacillus vulgaris, 4 strains of Pseudomonas aeruginosa, 2 strains of Citrobacter, 2 strains of group D streptococcus, 1 strain of Morganella, 1 strain of Enterobacter and 1 strain of Aeromonas. A proportion of 72.7%(16/22) of Escherichia coli were ESBL (+ ). All the 8 strains of Staphylococcus aureus were β-lactamase (+ ), and 7 of them were MRSA (87.5%). The median duration of total hospital stay and postoperative hospital stay in the non-SSI group were 33.0 days (26.0 days, 46.0 days) and 16.5 days (13.0 days, 21.0 days), which were significantly shorter than 37.0 days (31.0 days, 64.0 days) and 23.0 days (17.0 days, 32.0 days) in the SSI group (Z=2 582.00, 1 757.00, P<0.05). Conclusions The incidence of SSI is high after definitive operation because digestive tract fistula is a kind of abdominal contaminated wound. The common pathogens are Escherichia coli, Enterococcus, Klebsiella pneumonia and Staphylococcus aureus, some of which are drug resistant. Registry This study was registered in Chinese Clinical Trial Registry with the registry number of ChiCTR-EOC-14005670. Key words: Abdominal contaminated wound; Surgical site infection; Distribution of pathogens