1245. Staphylococcus aureus Mupirocin Resistance in Patients with Community-Onset Skin and Soft Tissue Infection
Session: Poster Abstract Session: Staphylococcal Resistance and Epidemiology
Saturday, October 22, 2011
Room: Poster Hall B1
Background: 

Decolonization measures, including intranasal mupirocin, are prescribed to prevent community-onset skin and soft tissue infections (SSTI).  Mupirocin resistance has emerged in areas with widespread use.  We aimed to measure the prevalence of mupirocin resistance in Staphylococcus aureus (SA) strains from SSTI patients before and after mupirocin administration.

Methods: 

480 patients with community-onset SSTI and SA colonization (in the nares, axilla, or groin) were recruited from the Emergency Departments (ED) of St. Louis Children’s and Barnes-Jewish Hospitals.  In addition to routine treatment, 75 patients received a hygiene education curriculum alone and 405 patients received education plus mupirocin (with or without antimicrobial baths) for 5 days.  Patients were followed up to 12 months with repeat colonization cultures.  All recovered SA isolates were tested for mupirocin resistance by PCR detection of the mupA gene and by E-test.

Results: 

At baseline, 8/480 patients (1.7%) carried a mupirocin resistant (mup-R) SA strain (20/1255 isolates, 1.6%).  Recent healthcare exposure, healthcare worker in home, and SSTI in prior year were not significant risk factors for carrying mup-R SA at baseline.  During follow-up, 6/403 (1.5%) patients with culture data carried mup-R SA.

Of 75 patients not prescribed mupirocin, 3 (4%) carried mup-R SA at baseline.  During follow-up, 1/67 (1.5%) patients with culture data carried mup-R SA.  Of 405 patients receiving mupirocin, 5 (1.2%) carried mup-R SA at baseline.  During follow-up, 5/336 (1.5%) patients with culture data carried mup-R SA.  Of patients not carrying mup-R SA at baseline, acquisition of mup-R SA during follow-up occurred in 0/65 (0%) patients not receiving mupirocin compared to 2/333 (0.6%) patients receiving mupirocin (p=0.7).

Overall, mupirocin resistance was detected in 41/1269 (3.2%) methicillin-resistant (MR) SA isolates compared to 2/725 (0.3%) methicillin-sensitive (MS) SA isolates (p<0.001). 

Conclusion: 

The overall prevalence of mupirocin resistance is low in SA isolates recovered in outpatients.  Administration of mupirocin did not significantly increase prevalence of mupirocin resistance.  Prevalence of mupirocin resistance is higher in MRSA isolates than MSSA isolates.


Subject Category: A. Antimicrobial agents and Resistance

Stephanie A. Fritz, MD1, Patrick G. Hogan, MPH1, Madeline Martin, BS1, Marcela Rodriguez, MD1, Ali Ainsworth, BA1, Carol Patrick1, Emma Epplin, BS2, Bernard C. Camins, MD, MSCR3 and Carey-Ann Burnham, PhD4, (1)Pediatric Infectious Diseases, Washington University School of Medicine, St Louis, MO, (2)Washington University School of Medicine, Saint Louis, MO, (3)Department of Medicine, Washington University School of Medicine, St. Louis, MO, (4)Pediatrics, Pathology and Immunology, Washington University School of Medicine, St Louis, MO

Disclosures:

S. A. Fritz, None

P. G. Hogan, None

M. Martin, None

M. Rodriguez, None

A. Ainsworth, None

C. Patrick, None

E. Epplin, None

B. C. Camins, Pfizer, Inc. : Consultant, Grant Investigator and Speaker's Bureau, Consulting fee, Research grant, Research support and Speaker honorarium

C. A. Burnham, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.