The Streptococcus milleri group--an unrecognized cause of disease in cystic fibrosis: a case series and literature review

Pediatr Pulmonol. 2008 May;43(5):490-7. doi: 10.1002/ppul.20809.


The "Streptococcus milleri" group (SMG) is increasingly recognized for their role in pyogenic infections including empyema and solid organ abscesses. However, SMG disease has rarely been identified in cystic fibrosis (CF). Inherent difficulties in both growing the organisms and distinguishing SMG from less virulent oropharyngeal viridans streptococci may have led to a decreased recognition of this as a CF pathogen. We report on six cases of SMG-related infection over a 4-year time-frame occurring within an adult CF clinic in Canada, and a further four cases identified through a literature review. SMG manifested disease as bronchopulmonary exacerbations in 7 of 10 patients, and 4 of 10 patients had extra-pulmonary dissemination of SMG infection. Noticeably, pulmonary exacerbations were frequently associated with atypically malodorous sputum. Furthermore, patients clinically responded to anti-microbial therapies with no anti-Pseudomonal activity. There was a consistent correlation of SMG disease and co-colonization with P. aeruginosa leading to speculation of polymicrobial interactions resulting in enhanced virulence. SMG deserves considerable attention as a potential pathogen within the airways of patients with CF.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Abscess / diagnosis
  • Abscess / drug therapy
  • Abscess / microbiology
  • Adolescent
  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Cystic Fibrosis / microbiology*
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Pelvis / diagnostic imaging
  • Pelvis / microbiology
  • Pelvis / pathology
  • Pseudomonas Infections / complications
  • Pseudomonas Infections / diagnosis
  • Pseudomonas Infections / drug therapy
  • Radiography, Thoracic
  • Sputum / microbiology
  • Streptococcal Infections / complications*
  • Streptococcal Infections / diagnosis*
  • Streptococcal Infections / drug therapy
  • Streptococcus milleri Group / drug effects
  • Streptococcus milleri Group / isolation & purification*
  • Tomography, X-Ray Computed


  • Anti-Bacterial Agents