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

Abstract

Determine the time of onset and microbiology of surgical site infections (SSIs) following head and neck free flap reconstructive surgeries. Retrospective cohort study. 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. 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. 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. 2b