Changes in the Nasal Colonization with Methicillin-Resistant Staphylococcus aureus in Children: 2004-2009

Abstract

Background Staphylococcus aureus is an important cause of infection, particularly in persons colonized with this organism. This study compared the annual prevalence and microbiological characteristics of methicillin-resistant S. aureus (MRSA) nasal colonization in Taiwanese children from 2004 through 2009. Risk factors for MRSA were determined for the overall study period.MethodsChildren from birth to ≤14 years of age presenting for health maintenance visits or attending 1 of 57 kindergartens were recruited. Nasal swabs were obtained, and a questionnaire was administered. The prevalence and microbiological characteristics of MRSA colonization were also calculated for two 3-year periods: 2004–2006 and 2007–2009.ResultsCultures of the anterior nares were positive for S. aureus in 824 (25.8%) of the 3,200 children, and MRSA colonization was found in 371 (11.6%) children. The prevalence of S. aureus colonization decreased from 28.1% in 2004–2006 to 23.3% in 2007–2009 (p<0.01), whereas the prevalence of MRSA colonization increased from 8.1% to 15.1% during this period (p<0.0001). Multivariate analysis revealed that the independent risk factors for MRSA carriage were different for male and female children, and also among age groups. Most MRSA isolates belonged to sequence type 59 (ST59) (86.3%); however, a multiresistant MRSA clone with ST338 background emerged in 2007–2009. Ten (62.5%) of the 16 MRSA isolates expressed the genotypic profile ST338/staphylococcal cassette chromosome mec VT/Panton-Valentine leukocidin-positive/staphylococcal enterotoxin B-positive, and differed only in their antimicrobial susceptibility patterns.ConclusionThe prevalence of nasal colonization by MRSA increased among healthy Taiwanese children from 2004–2006 to 2007–2009, despite an overall decrease in the prevalence of nasal colonization by S. aureus. A multiresistant MRSA clone characterized as ST338 was identified from these children.

Multidrug-resistant clones of community-associated meticillin-resistant Staphylococcus aureus isolated from Chinese children and the resistance genes to clindamycin and mupirocin

“…The ermA and ermC genes are usually the main resistant genes responsible. The ermB gene, formerly found in animal strains conferring constitutive resistance to erythromycin and clindamycin, has recently been observed in human isolates in Taiwan and Hong Kong (Lo et al, 2010). In the current study, the cMLS B phenotype was prevalent in all MLS Bresistant S. aureus isolates and the ermB gene was the most prevalent resistance gene in CA MLS B -resistant S. aureus isolates.…”

Comparative study of nasal bacterial carriage in pediatric patients from two different geographical regions

“…In the Eritrean cohort, we did not find that healthcare exposure was significantly associated with MRSA nasal carriage, a finding that has been widely reported in the previous literature [2,5,17,18] and in the German cohort of the current study. Due to relatively small sample sizes in this prospective study, associations may not have been detected, particularly for MRSA isolates.…”

“…Due to relatively small sample sizes in this prospective study, associations may not have been detected, particularly for MRSA isolates. In contrast, a relatively high prevalence of MRSA colonization was found (11.6%) for a cohort of healthy children aged ≤14 years in community settings in Taiwan over a 5-year period with increasing tendency, despite an overall decrease in the prevalence of nasal colonization by S. aureus [18]. Kuehnert et al [5] concluded that the S. aureus colonization prevalence in the nares was highest in participants 6-11 years old in the United States, whereas MRSA colonization was associated with age ≥60 years and being female but not with recent health-care exposure.…”

Risk factors and molecular analysis of Panton-Valentine leukocidin-positive methicillin-susceptible Staphylococcus aureus colonization and infection in children

“…In our previous studies, high Staphylococcal Enterotoxin B (SEB) gene carriage rate in S aureus was noted. 16,19 In this study, we wanted to find the definite carriage rate of community-associated (CA)-MSSA in Taiwan.…”