Twelve hundred abscesses operatively drained: an antibiotic conundrum?

BACKGROUND

The incidence of soft tissue infections from antimicrobial-resistant pathogens is increasing. This study evaluated the epidemiology of operatively drained soft tissue abscesses.

METHODS

This retrospective study evaluated 1,200 consecutive patients from 2002 to 2008 who underwent incision and drainage (I&D) in the main operating room. Patients were excluded for perirectal or hidradenitis infections.

RESULTS

Of 1,200 consecutive cases with an I&D, 1,005 patients had intraoperative cultures. The 1,817 positive isolates included gram-positive aerobes (1,180 [65%]), gram-negative aerobes (207 [11%]), anaerobes (416 [23%]), and fungi (14 [1%]). The most prevalent organism was Staphylococcus aureus, 30% (536), with 80% (431) being methicillin-resistant S aureus (MRSA). MRSA was the predominant organism in all except the breast abscesses. Anaerobes were identified primarily in the breast in diabetics, and in trunk and extremity abscesses in intravenous drug users. The most frequently prescribed empiric antibiotic was ampicillin/sulbactam (66%). The initial empiric antibiotic did not cover MRSA (82%; P < .001), resistant gram-negative aerobes (24%), and anaerobes (26%).

CONCLUSION

Gram-positive aerobes plus anaerobes represented approximately 80% of the pathogens in our series, with the anaerobic rates being underestimated. Empiric antibiotics should cover MRSA and anaerobes in patients with superficial abscesses drained operatively.