Article Text

Download PDFPDF
Pneumococcal lactational mastitis in a healthy woman
  1. Ayaka Ujita1,
  2. Hikohaku Ryu1,
  3. Hiroyuki Kobayashi1 and
  4. Mikiro Kato2
  1. 1Department of General Ineternal Medicine, Mito Kyodo General Hospital, Mito, Japan
  2. 2Department of Infectious Diseases, University of Tsukuba Hospital, Tsukuba, Japan
  1. Correspondence to Dr Mikiro Kato; k.mikiro{at}


We report a case of lactational mastitis complicated by Streptococcus pneumoniae bacteraemia in a breast feeding, healthy woman in her 20s. Numerous investigations showed that mastitis was the probable source of S. pneumoniae bacteraemia. While S. pneumoniae is known to cause non-lactational mastitis in patients with underlying diseases, such as systemic lupus erythematosus, reports of lactating mastitis in healthy individuals are scarce, with only six cases reported in the scientific literature published in English since 1995. Similar to previous reports, our patient had a good clinical course with antimicrobial therapy, and the infection was presumably transmitted from the asymptomatic child to the mother. Although the exact mechanisms that establish transmission from a child remain unclear, both host and pathogen factors, such as stagnant milk or bacterial virulence factors, are thought to play a key role. Caution should be exercised because serotypes not currently covered by pneumococcal vaccines are emerging.

  • General practice / family medicine
  • Vaccination/immunisation

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Contributors AU managed this patient and wrote this case report as the first author. HR supported AU. HK supported AU. MK supervised AU as the last author.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.