The Role of Staphylococcus aureus in Mastitis: A Multidisciplinary Working Group Experience

Sara Giordana Rimoldi, Paola Pileri, Martina Ilaria Mazzocco, Francesca Romeri, Giovanna Bestetti, Nunziata Calvagna, Claudia Tonielli, Lorenza Fiori, Anna Gigantiello, Cristina Pagani, Paolo Magistrelli, Alessandra Sartani, Annalisa De Silvestri, Maria Rita Gismondo, Irene Cetin

Research output: Contribution to journalArticlepeer-review


Background: Breastfeeding women are at risk of developing mastitis during the lactation period. Staphylococcus aureus has emerged as the community-acquired pathogen responsible for virulence (methicillin resistance and Panton-Valentine leukocidin toxin producing). Research aim: The aim was to compare the microorganisms responsible for mastitis and breast abscesses during breastfeeding. Methods: This observational study was conducted with a sample of women (N = 60) admitted to our hospital between 2016 and 2018. Participants affected by mastitis and breast abscess were studied and cared for by a multidisciplinary working group. A diagnostic breast ultrasound identified the pathology. Results: Twenty-six participants (43.3%) were affected by mastitis and 34 (56.7%) by breast abscess. The most common microorganism identified was Staphylococcus aureus (S. aureus; mastitis, n = 13; abscesses, n = 24). Methicillin resistance was identified in 21 (44.7%) S. aureus strains: 17 (80.9%) cases of abscess and four (19.1%) cases of mastitis. The median number of months of breastfeeding was smaller in the methicillin-resistant S. aureus (MRSA) cases (median = 3, range = 1–20 months) than in the methicillin-sensitive S. aureus (MSSA) cases (median = 6.5, range = 3–21 months). The Panton-Valentine leukocidin toxin gene was detected in 12 (25.5%) cases (MRSA, n = 8, 66.7%; MSSA, n = 4, 33.3%). Hospitalization was required more frequently in MRSA (n = 8, 38%; five Panton-Valentine leukocidin positive) than in MSSA cases (n = 5, 19%; one Panton-Valentine leukocidin positive). Four women out of the eight MRSA cases (50%) that were Panton-Valentine leukocidin positive stopped breastfeeding during mammary pathologies, three (37.5%) participants continued breastfeeding until the follow-up recall, and one case was lost at follow-up. Conclusion: Clinical severity was probably complicated by the presence of the Panton-Valentine leukocidin toxin, which required hospitalization more frequently.

Original languageEnglish
JournalJournal of Human Lactation
Publication statusAccepted/In press - Jan 1 2019


  • anatomy
  • breast
  • breastfeeding
  • human milk

ASJC Scopus subject areas

  • Obstetrics and Gynaecology


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