Objective      To investigate the clinical characteristics and drug resistance of deep sternal wound infection (DSWI) after cardiac surgery.       Methods      From January 2012 to December 2014

84 patients (≥18 years old) with secondary DSWI after cardiac surgery underwent the pectoralis major muscle flap transposition in our department

and the clinical data were retrospectively analyzed. The distribution of pathogens in the patients with DSWI and the drug resistance of pathogens were analyzed.       Results      Among these 84 patients

34 (40.5%) were females and the mean age was 54.6±14.8. There were 49 (58.3%) patients with type Ⅱ DSWI

17 (20.2%) patients with type Ⅰ DSWI and 18 (21.4%) patients with type Ⅲ DSWI. Both type I and type II DSWI patients showed typical clinical manifestations

such as fever

purulent exudate with wound dehiscence

sternal instability

and spontaneous pain in the surgical area. But type I DSWI patients were more likely to be associated with hypoproteinemia (P0.01)

and early chest X-ray or computerized tomography (CT) showed mediastinal widening (P0.01). Some patients with type Ⅲ DSWI showed only local symptoms at the surgical area. Microbiological diagnosis was available in 37 patients. The pathogens that were most commonly isolated in the patients with DSWI were Gram-negative bacilli (GNB

54.8%)

followed by methicillin-sensitive Staphylococcus aureus (23.7%). The most common pathogens in GNB were Pseudomonas aeruginosa

followed by Acinetobacter baumannii and Enterobacter cloacae. Pseudomonas aeruginosa resistant to imipenem and meropenem was 18.2%. Acinetobacter baumannii resistance was very serious

and its resistance to the clinical commonly used antibiotics was more than 70%. Enterobacter cloacae did not show the resistance to the most commonly used antibiotics. Staphylococcus aureus and Staphylococcus epidermidis showed 100% resistance to penicillin G

more than 80% resistance to clindamycin

and no resistance to tigecycline

vancomycin and linezolid.       Conclusion       DSWI often occurs within 1 month after cardiac surgery. Type II DSWI is the most common

and different types of DSWI exhibit different clinical features. The most common pathogens are GNB and Staphylococcus aureus

which have high resistance to commonly used antibiotics.