In 2001, the nasal carriage rate of MSSA was 28% and the nasal carriage rate of MRSA was just 0.8%. “We had a small—but important—reservoir of MRSA in our community,” Dr. Creech said.
The 2004 follow-up study revealed a 10-fold increase in MRSA nasal carriage. Of the 500 children swabbed, 46 (9.2%) were colonized with MRSA.
Of the 46 MRSA isolates, 45 were susceptible to rifampin, gentamicin, and trimethoprim-sulfamethoxazole. However, 25 (54%) were resistant to erythromycin and 12 (26%) were resistant to clindamycin.
Of the erythromycin-resistant isolates, eight (32%) showed characteristics of inducible resistance by the disk diffusion test. Only 4 of the 46 isolates (8%) expressed constitutive resistance to clindamycin.
Ten of the 46 isolates (21%) were positive for the cytotoxin PVL.