887. A Pilot Study of Indigenous Cutaneous Microbes in Patients with Skin Abscesses
Session: Poster Abstract Session: Bone, Joint, and Soft Tissue Infection
Friday, October 19, 2012
Room: SDCC Poster Hall F-H
Background: Previous studies have demonstrated an association between antibiotic use and development of skin abscesses.  This study investigates the hypothesis that antibiotic-induced alterations in residential skin microbes could predispose to skin abscess.

Methods: This was a case-control study of 25 patients with skin abscesses and 25 age matched controls.  All patients and controls completed a questionnaire.  The purulent drainage from the abscess was sent for culture.  Skin swab samples for DNA analysis of cutaneous microbes were taken from 4 quadrants around the abscess and the patient’s contralateral side.  Skin swab samples were taken from controls at the same site as their matched patient.  DNA was extracted and analyzed by qPCR.

Results: Eleven of the 25 patients had Methicillin Resistant Staphylococcus aureus (MRSA),12 had other organisms and in two, the sample was not available for culture.  Thirteen of 25 abscess patients were female and 12 of 25 control patients were female.  Cultures for the non-MRSA group grew coagulase negative Staphylococcus (3), Proteus sp (1), Methicillin-susceptible Staphylococcus aureus (2), Group B Streptococcus (1), Enterococcus (1), “mixed flora” (2), Corynebacteria sp (1) and no growth (1).  Antibiotic use in the prior 3 months occurred in 8 of 25 abscess patients and 3 of 25 controls (p=0.067).  Antimicrobial soap use was reported in 16/25 abscess patients and 17/25 controls (p=0.77).  Of the 10 MRSA strains available for testing, 9 were USA 300 and 1 was USA 100.  The DNA analysis demonstrated significantly higher density of Staphylococcus aureus (determined by nuc qPCR) in patients with abscesses than controls (p<0.0001) and compared to the patient's contralateral side (p=0.005).  The samples from the contralateral side demonstrated more nuc than controls (p<0.0001).  We detected mecA more commonly in the patients with abscesses than in controls (p=0.0029)

Conclusion: Skin abscesses correlate with S. aureus  in surrounding and contralateral skin. The prevalence of mecA was higher than anticipated, which may reflect selection for resistant cutaneous microbiota.

James Horton, MD, Medicine, Carolinas Medical Center, Charlotte, NC, Guillermo Perez, New York University, New York, NY, Zhan Gao, New York University School of Medicine, New York, NY, Sullivan D. Matthew, MD, Emergency Medicine, Carolinas Medical Center, Charlotte, NC and Martin Blaser, MD, FIDSA, New York University and Veterans Affairs Medical Center, New York, NY

Disclosures:

J. Horton, GSK: , Research support
Gilead: , Research support

G. Perez, None

Z. Gao, None

S. D. Matthew, None

M. Blaser, None

<< Previous Abstract | Next Abstract

Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 17th with the exception of research findings presented at the IDWeek press conferences.