Pyothorax Caused by Arcanobacterium haemolyticum and Staphylococcus aureus Co-infection: A Case Report

Area of Science:

• Infectious Diseases
• Microbiology
• Pulmonology

Background:

• Arcanobacterium haemolyticum is known to cause pharyngeal and skin infections.
• Severe systemic infections, such as pyothorax (pleural effusion), are rare complications.
• Co-infections involving A. haemolyticum are infrequently reported.

Observation:

• An 80-year-old woman with diabetes mellitus developed a massive left pleural effusion 19 days after admission for orthopedic surgery.
• Chest radiography confirmed the significant pleural effusion.
• The patient presented with a left femoral neck fracture and a right first toe ulcer.

Findings:

• Pleural fluid cultures revealed a polymicrobial infection with both Staphylococcus aureus and Arcanobacterium haemolyticum.
• This represents the first reported case of Arcanobacterium haemolyticum pyothorax with bacterial co-infection.
• Only four cases of pyothorax attributed to A. haemolyticum have been previously documented in the literature.

Implications:

• This case highlights the potential for Arcanobacterium haemolyticum to cause severe systemic infections, including pyothorax, especially in immunocompromised individuals.
• The findings underscore the importance of considering A. haemolyticum in the differential diagnosis of pleural effusions, particularly in polymicrobial infections.
• Further research is warranted to understand the pathogenic mechanisms and optimal treatment strategies for A. haemolyticum-associated pyothorax and co-infections.