P45 – Microbiology and resistance patterns in surgical site infections after open reduction and internal fixation (ORIF)

Author(s):
Neil Pathak, Vanessa Ho, Taylor Klein, Nisha Iyer, Arun Kottarathara, Sebastian Schubl, Farshad Bagheri, Jamaica Hospital Medical Center

Background: Infectious complications after ORIF lead to increased hospital length of stay, long-term physical limitations, and reduced overall quality of life. Greater understanding of the microbiology and resistance patterns of these infections is required to guide appropriate empiric antibiotic therapy and preoperative prophylaxis regimens.

Hypothesis: We hypothesize that the most common pathogens isolated would be sensitive gram-positive organisms. We secondarily hypothesize that patients with chronic medical conditions or recent hospitalization would be more likely to exhibit more virulent pathogens.

Methods: A retrospective review was performed on patients who received ORIF between 2009-2011 at a community teaching hospital and developed a surgical site infection. Patient demographics, clinical risk factors, microbiology, and outcome data were collected. The Chi square test was utilized to determine association between risk factors and specific microorganisms.

Results: Fifty-nine patients (35 male) were included in the study (mean age 52.7 y, SD 19.9). The most common ORIF performed was hip/knee with 17 cases (29%). Forty-four patients (75%) required antibiotics at discharge. Two patients died (4%). Twenty-seven (46%) patients had gram positive and 12 (20%) had gram negative organisms identified. S. aureus was the most common causative agent, in 23 patients (39%): 12 methicillin resistant (MRSA), 10 methicillin sensitive (MSSA), and 1 with both. Other causative agents isolated included enterobactericeae (9%), pseudomonas (8%), enterococcus (7%), acinetobacter (3%), and fungi (3%). Isolation of MRSA was associated with prolonged preoperative hospital stay and recent antibiotic use (p<0.05). Isolation of MSSA was associated with a history of a chronic skin condition (p<0.05).

Conclusions: The treatment of infectious complications following ORIF is an ongoing challenge. Patients with a prolonged hospital stay or recent antibiotic use are at risk of MRSA infection. Consideration should be given to routine MRSA prophylaxis or MRSA eradication in high risk patients with mupirocin or chlorhexidine baths. Patients with presumed infection following ORIF should be treated with empiric antibiotics active against MRSA and gram negative organisms until final culture results are available.