Pyomyositis caused by Streptococcus pneumoniae after allogeneic hematopoietic stem cell transplantation

Area of Science:

• Infectious Diseases
• Hematology
• Transplantation Medicine

Background:

• Pyomyositis, a bacterial infection of muscle, is typically classified as tropical or non-tropical.
• Non-tropical pyomyositis commonly affects immunocompromised individuals, with Staphylococcus aureus being the most frequent pathogen.
• Infection by Streptococcus pneumoniae is an infrequent cause of pyomyositis and has not been previously documented post-allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Observation:

• This report details a unique case of pyomyositis caused by Streptococcus pneumoniae affecting the bilateral erector spinae muscles.
• The patient developed symptoms 34 months after undergoing allo-HSCT.
• Initial treatment with intravenous benzylpenicillin potassium for four weeks resulted in a clinical response.

Findings:

• Streptococcus pneumoniae is an uncommon cause of pyomyositis.
• This case represents the first reported instance of pyomyositis due to S. pneumoniae following allo-HSCT.
• S. pneumoniae bacteremia, though rare after HSCT, warrants consideration for pyomyositis in affected recipients.

Implications:

• The findings underscore the importance of considering pyomyositis in the differential diagnosis of S. pneumoniae bacteremia in allo-HSCT recipients.
• Prompt and accurate diagnosis, coupled with appropriate antibiotic selection, is crucial for effective pyomyositis management.
• This case expands the understanding of potential infectious complications after allo-HSCT, emphasizing the need for vigilance against unusual pathogens.