Community-Acquired Necrotizing Pneumonia Caused by ST72-SCCmec Type IV-Methicillin-Resistant Staphylococcus aureus in...

Area of Science:

• Infectious Diseases
• Microbiology
• Pulmonology

Background:

• Community-associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) is increasingly recognized globally.
• The Panton-Valentine leukocidin (PVL)-negative ST72-SCCmec type IV strain is prevalent in Korea, typically causing skin/soft tissue infections and healthcare-associated pneumonia.
• Community-acquired pneumonia (CAP) caused by this specific CA-MRSA strain has not been previously reported in Korea.

Purpose of the Study:

• To report the first cases of community-acquired pneumonia (CAP) caused by the PVL-negative ST72-SCCmec type IV CA-MRSA strain in Korea.
• To raise awareness of this specific CA-MRSA strain as a potential cause of severe CAP, even in patients without traditional risk factors.

Main Methods:

• Case report of two patients diagnosed with CAP.
• Identification of the causative pathogen as PVL-negative ST72-SCCmec type IV CA-MRSA.
• Clinical review of patient histories, focusing on risk factors for MRSA acquisition.

Main Results:

• Two patients presented with severe CAP attributed to the PVL-negative ST72-SCCmec type IV CA-MRSA strain.
• Neither patient had identifiable risk factors typically associated with MRSA acquisition.
• The findings suggest this strain can cause severe pulmonary infections beyond skin and soft tissue infections.

Conclusions:

• CA-MRSA, specifically the PVL-negative ST72-SCCmec type IV strain, should be considered in the differential diagnosis of severe CAP in Korea.
• The absence of typical MRSA risk factors does not exclude CA-MRSA as the causative agent in severe CAP.
• These cases underscore the evolving epidemiology of CA-MRSA and its potential to cause severe pneumonia, including necrotizing forms.