Genetic characterization of erythromycin- and methicillin-resistant community-acquired Staphylococcus aureus isolated...

Area of Science:

• Microbiology
• Infectious Diseases
• Genetics

Background:

• Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a growing public health concern, particularly in pediatric populations.
• Understanding the genetic makeup and toxin production of CA-MRSA is crucial for effective treatment and control.

Purpose of the Study:

• To determine the prevalence of Panton-Valentine leukocidin (PVL) toxin, SCCmec, and accessory gene regulator (agr) types in pediatric CA-MRSA isolates from Texas.
• To characterize the genetic basis of macrolide resistance in these strains.

Main Methods:

• Analysis of 197 pediatric CA-MRSA isolates collected in Texas.
• Typing of SCCmec and agr genes.
• Detection of PVL toxin and msrA gene.

Main Results:

• The majority of pediatric macrolide-resistant, clindamycin-susceptible CA-MRSA isolates were PVL-positive, belonged to SCCmec type IV, and agr type I.
• The msrA gene was identified as the primary determinant for macrolide resistance in these strains.
• PVL-negative strains, characterized by SCCmec type II and agr type II, were infrequently detected but persistently present.

Conclusions:

• Pediatric CA-MRSA in Texas are frequently characterized by PVL toxin production and specific genetic profiles associated with macrolide resistance.
• The consistent presence of PVL-negative strains highlights the diverse epidemiology of CA-MRSA in the community.
• These findings have implications for antimicrobial stewardship and infection control strategies in pediatric healthcare settings.