Intramammary infusion of a live culture of Lactococcus lactis in ewes to treat staphylococcal mastitis

Sebastian Alessandro Mignacca, Simone Dore, Liliana Spuria, Pietro Zanghì, Benedetta Amato, Ilaria Duprè, Federica Armas, Elena Biasibetti, Cristina Camperio, Stefano A. Lollai, Maria Teresa Capucchio, Eugenia Agnese Cannas, Vincenzo di Marco Lo Presti, Cinzia Marianelli

Research output: Contribution to journalArticlepeer-review


Purpose. Alternatives to antibiotic therapy for mastitis in ruminants are needed. We present an evaluation, in two trials, of the efficacy of an intramammary infusion of a live culture of Lactococcus lactis for the treatment of subclinical and clinical mastitis in ewes. Methodology. In total, 67 animals were enrolled: 19 lactating ewes (study 1), including healthy (N=6) and coagulase-negative staphylococci (CNS)-infected ewes (N=13); and 48 lactating ewes (study 2) with either CNS mastitis (N=32), or Staphylococcus aureus mastitis (N=16), for a total of 123 mammary glands. Intramammary infusions were performed with either L. lactis or PBS for 3 (study 1) or 7 (study 2) consecutive days. Antibiotic-treated and untreated control glands were included. Milk samples for microbiology, somatic cell analysis and milk production were collected before and after treatment. Results/Key findings. L. lactis rapidly activated the mammary glands’ innate immune response and initiated an inflammatory response as evidenced by the recruitment of polymorphonuclear neutrophils and increased somatic cell counts. But while leading to a transient clearance of CNS in the gland, this response caused mild to moderate clinical cases of mastitis characterized by abnormal milk secretions and udder inflammation. Moreover, S. aureus infections did not improve, and CNS infections tended to relapse. Conclusion. Under our experimental conditions, the L. lactis treatment led to a transient clearance of the pathogen in the gland, but also caused mild to moderate clinical cases of mastitis. We believe it is still early to implement bacterial formulations as alternatives in treating mastitis in ruminants and further experimentation is needed.

Original languageEnglish
Article number000641
Pages (from-to)1798-1810
Number of pages13
JournalJournal of Medical Microbiology
Issue number12
Publication statusPublished - Dec 1 2017


  • Antibiotic alternative
  • Ewes
  • Intramammary infusion
  • Lactococcus lactis
  • Staphylococcal mastitis

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)


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