Clinical aspects of invasive infection with Streptococcus dysgalactiae subsp. equisimilis in elderly patients

The number of patients with severe invasive infections (mainly exhibiting bacteremia) with Streptococcus dysgalactiae subsp. equisimilis (SDSE) has been increasing worldwide. We herein report the clinical aspects of invasive infections (cellulitis, pneumonia, and urosepsis) occurring with SDSE in 13 elderly patients (mean age 84 years, range 69-99 years) diagnosed at a hospital for elderly individuals during the period January 2005-June 2009. Ten subjects had underlying diseases, including neurologic disorders, diabetes mellitus, and others. Eleven patients presented to the hospital emergency department, and the most common symptom was high fever or respiratory distress. Primary care and emergency department doctors treating elderly patients with high fever should keep in mind invasive SDSE infection as a differential diagnosis, especially when an elderly person has underlying illnesses. To detect SDSE in elderly subjects, blood cultures should be obtained before the administration of antimicrobials because, as we found, the patients' symptoms were limited.