Treatment of Antimicrobial-Resistant Gram-Positive Infections (MRSA, VISA, VRSA) in Children

Staphylococcus aureus is a leading cause of both community and hospital acquired severe and life threatening infections such as bacteremia, infective endocarditis, osteomyelitis, arthritis, cellulitis, and pneumonia. Methicillin resistant S. aureus (MRSA) is defined as oxacillin minimum inhibitory concentration (MIC) >4 mcg/mL, and has increased in prevalence worldwide as both a healthcare-associated and a community-associated pathogen. Vancomycin is the treatment of choice for all invasive MRSA infections especially in life threatening ones in children. A number of community associated MRSA isolates remain susceptible to clindamycin and trimethoprim/sulphametoxazole (TMP-SMX). In communities the prevalence of MRSA colonization and infection is high (>10 percent) and the prevalence of clindamycin resistance is low (<10 percent) clindamycin may be used for empiric therapy.Vancomycin intermediate S. aureus (VISA) is defined as a vancomycin MIC 4 to 8 mcg/mL and vancomycin resistant S. aureus (VRSA) MIC >16 mcg/mL. VISA strains have variable susceptibility patterns to linezolid, chloramphenicol, gentamycin, rifampin, TMP-SMX and tetracycline. VISA and VRSA isolates have usually been found susceptible to linezolid, quinopristin/dalfopristin and daptomycin. However clinical experience of quinopristin/dalfopristin and daptomycin in children are limited.