The time course and microbiology of surgical site infections after head and neck free flap surgery.

OBJECTIVES/HYPOTHESIS: Determine the time of onset and microbiology of surgical site infections (SSIs) following head and neck free flap reconstructive surgeries.

STUDY DESIGN: Retrospective cohort study.

METHODS: All 504 free flap surgical cases (484 patients) performed April 1, 2009 to September 30, 2013 were reviewed; SSIs occurring ≤30 days postoperatively were evaluated. Admission screening for methicillin-resistant Staphylococcus aureus (MRSA) colonization was performed on all patients.

RESULTS: Flap-recipient site infections (flap SSIs) occurred in 67 cases (13.3%), one-third week 1 postoperatively, one-third week 2, one-third days 15 to 30; 45% occurred after hospital discharge. Wound cultures were polymicrobial, but 25% grew only normal oral flora, whereas 75% grew pathogens not part of normal oral flora, such as gram-negative bacilli (44% of cases), MRSA (20%), and methicillin-sensitive S aureus (MSSA) (16%). The frequency of these pathogens did not vary significantly by the time of SSI onset. In 67%, cultures included at least one pathogen resistant to the prophylactic antibiotic used. Clindamycin prophylaxis was a significant risk factor for flap SSI and for early partial or complete flap loss from infection. Donor SSIs occurred in 22 cases (4.4%), 95% >1 week postoperatively, and MRSA or MSSA were the primary pathogens in 89%. Of the 25 patients colonized with MRSA on admission, 40% developed a flap or donor SSI, a rate significantly higher than in non-colonized patients.

CONCLUSIONS: Gram-negative bacilli, MRSA, and MSSA were significant SSI pathogens, and late onset of infection was common. Better screening, decolonization, and prophylaxis may reduce SSI rates.

LEVEL OF EVIDENCE: 2b