Clin Infect Dis 2015 Aug 3
Most culture results in cellulitis are negative, and most causes remain unidentified.
Multicenter study of 30 adults with acute cellulitis (duration < 4 days, most lower extremity) without drainage, presenting to ED.
None had received abx =< 72 hours prior to biopsy.
All pts had punch biopsy from center of infection and comparable contralateral side, also needle aspirate from infection.
Specimens analyzed by standard culture, PCR and DNA sequencing.
Biopsies negative in 84%.
2 had MSSA by culture and PCR.
Sequencing revealed S aureus in 24% and 33% of infected and uninfected specimens, respectively.
MRSA and S pyogenes NOT detected by culture or PCR from any infection-site specimens!
– Cultures of cellulitis are pretty much useless.
– Remember the DDx of cellulitis!
– Ectopic pathogens can cause local release of inflammatory mediators due to anatomic changes.