Community-acquired bacteremic Streptomyces atratus pneumonia in an immunocompetent adult: a case report

Miguel Angel Ariza-Prota, Ana Pando-Sandoval, David Fole-Vázquez, Marta García-Clemente, Teresa Budiño, Pere Casan

Streptomyces spp. are aerobic, Gram-positive bacteria of the order Actinomycetales, known for their ability to produce antimicrobial molecules such as streptomycin. Pneumonia due to Streptomyces is considered to be rare and limited to immunocompromised patients. Streptomyces spp. are only rarely associated with invasive systemic infections. To our knowledge, we report the first documented case of community-acquired Streptomyces atratus bacteremic pneumonia in an immunocompetent patient. We describe a case of Streptomyces atratus bacteremic pneumonia in an otherwise healthy, 77-year-old Spanish man. Streptomyces identified by 16S ribosomal RNA sequencing grew in multiple blood cultures and bronchoalveolar lavage cultures. The infection resolved completely after treatment with imipenem and amoxicillin/clavulanic acid for 2 months. The majority of cases reported in the literature make reference to the difficulty of determining the pathogenic role of Streptomyces spp. Usually considered a contaminant, the pathogenic role of Streptomyces spp. is easier to confirm when the species is isolated from a catheter tip and, in the case of blood cultures, in more than one sample with a high count of colonies. To our knowledge, we report the first documented case of Streptomyces atratus bacteremic pneumonia in an immunocompetent patient. As the experience is limited, further studies are needed to better understand the interpretation of the isolates of the genus Streptomyces; the predisposing factors for infection; and the course, treatment, and evolution of these infections.