Community-associated Methicillin-resistant Staphylococcus aureus Disease in Children in Taiwan: The Importance of Antibiotic Stewardship

Abstract

Since it was first reported in the 1960s, methicillinresistant Staphylococcus aureus (MRSA) has been a major cause of a variety of infectious syndromes in patients exposed to the healthcare environment.1 In Taiwan, MRSA was first documented in the early 1980s and increased rapidly in the 1990s.1 Nowadays, MRSA is endemic in most hospitals in Taiwan and accounts for 53–83% of all S. aureus isolates.1 However, from the late 1990s, community-associated (CA) MRSA has become a major concern worldwide.2 CA-MRSA causes a variety of diseases, ranging from skin or soft tissue infection to severe invasive diseases, such as sepsis, necrotizing pneumonia, and necrotizing fasciitis.1,2 CA-MRSA strains worldwide are thought to have unique microbiological characteristics such as limited antibiotic resistance (except to β-lactam antimicrobial agents), different exotoxin gene profiles (e.g. Panton–Valentine leukocidin; PVL), and smaller staphylococcal cassette chromosome mec (SCCmec) variants: either SCCmec type IV, or less frequently, type V or a variant, type VT. In Taiwan, CA-MRSA infections have been reported increasingly in pediatric patients since 2002. The rate of MRSA was estimated as 44% in pediatric cases of CA S. aureus infections, after pooling the data from retrospective studies with similar designs between 1997 and 2001.1 Currently, the CA-MRSA strains that cause infection in Taiwan are characterized by multiple antibiotic resistance (including clindamycin, erythromycin, tetracycline and chloramphenicol), which differs from those in the United States,4 with skin and superficial soft tissue infections being the major clinical manifestations. However, significant morbidity and mortality from CA-MRSA infections have been reported increasingly in pediatric cases.1,5 They have common pulsed-field gel electrophoresis (PFGE) patterns that differ from those of the major pandemic clones of hospitalacquired MRSA isolates. Also, the genotype has been identified as sequence type (ST) 59 by multilocus sequencing typing; they possess PVL and staphylococcal enterotoxin B and may have acquired SCCmec type VT (now designated type VII), or less frequently, type IV.4,6,7 The importance of antibiotic stewardship for CA-MRSA disease in Taiwan can be demonstrated in four different ways. Several previous community-based studies and the latest islandwide survey have assessed the extent of MRSA in the community, and have revealed a high prevalence of colonization with multidrug-resistant MRSA.3,6,8 Compared with that among healthy children during the period 2001–2002, the prevalence of nasal MRSA colonization among healthy