title: Risk factors for Staphylococcus aureus postpartum breast abscess.
abstract: BACKGROUND
  Staphylococcus aureus (SA) breast abscesses are a complication of the postpartum period. Risk factors for postpartum SA breast abscesses are poorly defined, and literature is conflicting. Whether risk factors for methicillin-resistant SA (MRSA) and methicillin-susceptible SA (MSSA) infections differ is unknown. We describe novel risk factors associated with postpartum breast abscesses and the changing epidemiology of this infection.
  
  
  METHODS
  We conducted a cohort study with a nested case-control study (n = 216) involving all patients with culture-confirmed SA breast abscess among >30 000 deliveries at our academic tertiary care center from 2003 through 2010. Data were collected from hospital databases and through abstraction from medical records. All SA cases were compared with both nested controls and full cohort controls. A subanalysis was completed to determine whether risk factors for MSSA and MRSA breast abscess differ. Univariate analysis was completed using Student's t test, Wilcoxon rank-sum test, and analysis of variance, as appropriate. A multivariable stepwise logistic regression was used to determine final adjusted results for both the case-control and the cohort analyses.
  
  
  RESULTS
  Fifty-four cases of culture-confirmed abscess were identified: 30 MRSA and 24 MSSA. Risk factors for postpartum SA breast abscess in multivariable analysis include in-hospital identification of a mother having difficulty breastfeeding (odds ratio, 5.00) and being a mother employed outside the home (odds ratio, 2.74). Risk factors did not differ between patients who developed MRSA and MSSA infections.
  
  
  CONCLUSIONS
  MRSA is an increasingly important pathogen in postpartum women; risk factors for postpartum SA breast abscess have not changed with the advent of community-associated MRSA.
authors: Division of Infectious Diseases, Department of Health Care Quality, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA. wbranche@bidmc.harvard.edu
authors: Westyn
authors: W
authors: Branch-Elliman
authors: Toni H
authors: TH
authors: Golen
authors: Howard S
authors: HS
authors: Gold
authors: David S
authors: DS
authors: Yassa
authors: Linda M
authors: LM
authors: Baldini
authors: Sharon B
authors: SB
authors: Wright
mesh_terms: D000038:Abscess / Q000453:epidemiology* / Q000382:microbiology; D000328:Adult; D001940:Breast / Q000382:microbiology / Q000473:pathology; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008413:Mastitis / Q000453:epidemiology* / Q000382:microbiology; D049590:Postpartum Period; D011247:Pregnancy; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000302:isolation & purification*