Virulence and Antibiotic Resistance Profiles of Staphylococcus aureus Isolated from Epidermal Growth Factor Receptor...

Area of Science:

• Dermatology
• Microbiology
• Oncology

Background:

• Cutaneous adverse reactions (CARs), including papulopustular eruptions and paronychia, are frequent side effects of epidermal growth factor receptor (EGFR) inhibitor cancer therapy.
• Emerging evidence suggests a link between Staphylococcus aureus and the development of these EGFR inhibitor-associated CARs.

Purpose of the Study:

• To investigate the role of S. aureus in the pathogenesis of CARs associated with EGFR inhibitor therapy.
• To characterize S. aureus strains isolated from CARs, focusing on antibiotic resistance, biofilm formation, and virulence factors.

Main Methods:

• Observational prospective study involving 42 S. aureus strains isolated from patients with CARs.
• Analysis of antibiotic resistance patterns, biofilm formation capacity, and production of soluble virulence factors (DNase/esculinase).
• Multiplex polymerase chain reaction (PCR) was used to identify virulence and resistance genes.

Main Results:

• S. aureus was detected in 90% of CAR lesions, with genetic identity between nasal and skin isolates in 33% of cases.
• High resistance rates were observed for penicillins (85%) and tetracyclines (57%), but not fluoroquinolones, vancomycin, or rifampicin.
• All S. aureus isolates formed biofilms; DNase/esculinase production correlated with CAR severity, with an enzymatic score indicating an 18-fold increased risk for severe reactions.

Conclusions:

• S. aureus plays a significant role in exacerbating EGFR inhibitor-induced CARs through antibiotic resistance, biofilm production, and virulence factor expression.
• Routine microbial screening, including nasal swabs, and antibiogram-guided therapy are recommended for managing CARs.
• The developed enzymatic score shows potential as a predictive biomarker for CAR severity.