Changing epidemiology of methicillin-resistantStaphylococcus aureuscolonization in paediatric intensive-care units

Abstract

SUMMARYCommunity-associated methicillin-resistant S. aureus (CA-MRSA) accounts for a growing proportion of hospital-onset infections, and colonization is a risk factor. This study aimed to determine changes in the prevalence of CA-MRSA colonization in paediatric intensive-care units (ICUs). A total of 495 paediatric patients colonized with MRSA from neonatal, medical, surgical, and cardiac ICUs between 2001 and 2009 were identified. Isolates were characterized by spa type, staphylococcal cassette chromosome (SCC) mec type and the presence of the genes encoding Panton-Valentine leukocidin (PVL). The proportion of patients colonized with MRSA remained stable (average 3 . 2 %). The proportion of isolates with spa type 1, SCCmec type IV and PVL increased over time to maximums in 2009 of 36 . 1% (P<0 . 001), 54 . 2% (P=0 . 03) and 28 . 9% (P=0 . 003), respectively. Antibiotic susceptibility patterns showed increasing proportions susceptible to clindamycin, gentamicin, tetracycline and trimethoprim-sulfamethoxazole (P values <0 . 001). In conclusion, the proportion of MRSA-colonized children in ICUs with CA-MRSA increased significantly over time.

Emergence of Community-Genotype Methicillin-ResistantStaphylococcus aureusin Korean Hospitals: Clinical Characteristics of Nosocomial Infections by Community-Genotype Strain

“…A prospective study in Colombia showed the CA-MRSA presented as primary bacteremia and SSI as result of nosocomial infection [23]. While the pathogenicity has not been fully elucidated, considering that the most superficial incisional SSI develops due to contamination of the surgical site by endogenous flora of the patient [24], and there is an increasing prevalence of colonization and infection by community-genotype MRSA strains in healthcare settings [1025], operations for solid tumors may contribute to colonization of community-genotype MRSA and the subsequent development of infections. On the other hand, underlying neurologic disease and care in the ICU were found to be associated with MRSA infections by hospital-genotype strains.…”

Community-Associated Methicillin-Resistant Staphylococcus aureus Case Studies

“…More recently, USA300 was found to account for 28 % of healthcare-associated bloodstream infections (contact with healthcare facility within year prior to admission) and 20 % of nosocomial infections (positive blood culture more than 48 h after admission)[9]. In parallel, an increase in colonization with strains consistent with USA300 was also noted in pediatric ICU patients from 2001 to 2009, where in 2009 36 % colonization isolates had a spa -type consistent with USA300 and 29 % of isolates were PVL positive [72]. …”

“…In that context, the occurrence of a decreased susceptibility to vancomycin in USA300 isolates is not surprising [72, 75], but the prospect of multidrug resistance in strains with increased virulence is a source of great concern.…”

Update on Epidemiology and Treatment of MRSA Infections in Children

“…In 2001-9 at the Children’s Hospital of Boston, among 15,295 pediatric ICU patients, 3.2% (495/15,295) carried MRSA in the nares, and the proportion of MRSA isolates increased that carried SCC mec IV (p=0.03), and pvl (p=0.003). No isolate was pvl + in 2003, but 28.9% were pvl + in 2009 (21). At Case Western Reserve University, the incidence of MRSA infections in the NICU was higher in 2006-8 compared with 2001-5.…”