Staphylococcus aureus pyomyositis compared with non-Staphylococcus aureus pyomyositis

Area of Science:

• Infectious Diseases
• Bacteriology
• Musculoskeletal Infections

Background:

• Pyomyositis is an acute bacterial infection of skeletal muscle, often originating from hematogenous spread and typically involving abscess formation.
• It is crucial to understand the clinical nuances between different causative agents, particularly Staphylococcus aureus (SA), and the evolving landscape of antibiotic resistance.

Purpose of the Study:

• To compare the clinical presentation of pyomyositis caused by Staphylococcus aureus versus non-Staphylococcus aureus pathogens.
• To investigate the incidence and frequency of methicillin-resistant Staphylococcus aureus (MRSA) pyomyositis over time.

Main Methods:

• A retrospective chart review was conducted across three institutions in two cities.
• Data from sixty pyomyositis cases identified between 1990 and 2010 were analyzed.

Main Results:

• Of the sixty cases, 29 were attributed to Staphylococcus aureus (SA) and 31 to other bacterial etiologies or were culture-negative.
• Patients with a history of trauma were more likely to have SA pyomyositis, and SA-infected patients were generally younger.
• The first MRSA case was documented in 2005, with no significant increase in its frequency in the subsequent five years.

Conclusions:

• Pyomyositis is an underrecognized emerging infection with potential for severe complications like bacteremia.
• Despite the rise of MRSA in other conditions, methicillin-sensitive SA remains a significant cause of pyomyositis.
• Empirical SA treatment is recommended for all pyomyositis patients until culture results are available.