Monomicrobial Staphylococcus aureus Necrotizing Soft Tissue Infection: A Case Report and Review of Literature.

Necrotizing soft tissue infections (NSTIs) are severe infections that cause destruction of tissues, including the skin, fascia, and muscle. Here, we discuss a case of a monomicrobial NSTI caused by methicillin-resistant Staphylococcus aureus (MRSA). The patient presented with signs of sepsis and a large, pustular, purulent, and draining skin infection, consisting of 50-60 lesions that had coalesced into a large collection in the right lumbar region and tracked inferolaterally toward the buttocks. This case provides an opportunity to discuss the pathophysiology underlying the progression of MRSA abscesses to NSTIs, as well as the diagnosis and treatment of these infections. The patient was treated with intravenous antibiotics and required surgical debridement, which revealed extension of the infection into the subcutaneous tissue, muscle, deep lumbar fascia, and posterior layer of the thoracolumbar fascia. This case highlights the unusual anatomical location and monomicrobial etiology of an NSTI. It also underscores the diagnostic challenges in determining the severity of infection, as existing diagnostic tools for NSTIs may have limited utility in atypical anatomical regions and in infections arising from uncommon sources.