ABSTRACT
BACKGROUND: The prevalence of nasopharyngeal colonization with Staphylococcus aureus can reach 20-30% among the population, which can lead to invasive infection. AIM: To investigate the prevalence of colonization among different age groups, and analyse S. aureus strain-specific virulence patterns. METHOD: For analysis of the prevalence of colonization, groups consisting of newborns, healthy volunteers aged 5-60 years, and nursing home residents aged >80 years were examined with nasopharyngeal swabs. After S. aureus was cultured, genetic analysis and phenotypic virulence testing were performed by cell-based assays. FINDINGS: Among 924 volunteers, the overall colonization rate was approximately 30%, with a peak in subjects aged 5-10 years (49%). Neonates and subjects aged >80 years showed different distributions of clonal clusters. Overall, the strains of all age groups exhibited virulence characteristics that can contribute to the development of infection. In particular, the neonatal strains exhibited a high incidence of toxin genes that resulted in increased cytotoxic effects compared with the other strains tested. CONCLUSIONS: Colonizing strains showed a virulence profile in all age groups, which may lead to the establishment of invasive infection. Consequently, decolonization measures could be considered for selected patients depending on the risk of infection.
Subject(s)
Carrier State/epidemiology , Nasopharynx/microbiology , Staphylococcal Infections/epidemiology , Staphylococcus aureus/isolation & purification , Virulence Factors/analysis , Adolescent , Adult , Aged , Aged, 80 and over , Carrier State/microbiology , Child , Child, Preschool , Female , Genotype , Humans , Infant , Infant, Newborn , Male , Middle Aged , Phenotype , Prevalence , Staphylococcal Infections/microbiology , Staphylococcus aureus/genetics , Staphylococcus aureus/pathogenicity , Virulence , Virulence Factors/genetics , Young AdultABSTRACT
Insulin-like growth factor binding protein (IGFBP)-2 has mitogenic effects in normal and neoplastic cells. The purpose of this study is to examine the diagnostic and prognostic significance of elevated IGFBP-2 levels in children with AML after hematopoietic stem cell transplantation (HSCT) at relapse and continuous complete remission (CCR). In 27 children with AML (mean age 13.6+/-5.3 years; patients in remission n=15 with relapse n=12) serum parameters of IGFBP-2, IGFBP-3, IGF-I and IGF-II were analyzed up to 18 months after HSCT by RIA. AML-patients with evidence of relapse demonstrated a continuous increase of IGFBP-2 levels during the follow-up. At day 100 after HSCT, IGFBP-2 concentrations were significantly higher in patients with relapse than in children without relapse (7.4+/-4.0 standard deviation score (SDS) vs 3.9+/-1.7 SDS; P=0.01). Serum IGFBP-2 was identified as an independent factor for the prediction of relapse. Furthermore, the probability of relapse-free survival (RFS) in patients with IGFBP-2 >4.5 SDS at day 100 after HSCT was 31% compared to patients with IGFBP-2 <4.5 SDS was 72% (P=0.004). Patients with IGFBP-2 concentration up to 4.5 SDS more likely developed a relapse and had a poorer outcome. Identification of these patients allows a more individualized and aggressive adjuvant treatment and follow-up.
Subject(s)
Insulin-Like Growth Factor Binding Protein 2/blood , Leukemia, Myeloid, Acute/therapy , Stem Cell Transplantation/adverse effects , Adolescent , Biomarkers/blood , Bone Marrow Transplantation , Child , Female , Follow-Up Studies , Humans , Insulin-Like Growth Factor Binding Protein 3/blood , Insulin-Like Growth Factor I/metabolism , Insulin-Like Growth Factor II/metabolism , Male , Recurrence , Risk Assessment , Time FactorsABSTRACT
SUMMARY: Insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) may play an important role in tumor proliferation. This study aimed to investigate the IGF system in children with acute leukemia prior to and after hematological stem cell transplantation (HSCT). In 51 patients (AML n=27; ALL n=24; mean age 11.2+/-4.8 years), serum parameters (IGF-I,-II, IGFBP-2,-3) were investigated up to 18 months after HSCT by RIA. Patients with AML showed a significant increase of IGFBP-2 up to 100 days after HSCT (mean +/-s.d. prior to HSCT: 3.2+/-3.6 SDS vs 100 days after HSCT: 5.3 degrees +/-3.4 SDS, P=0.005). Furthermore, IGF-I and IGFBP-3 were significantly decreased (IGF-I: -0.3+/-1.5 vs -0.7 +/-1.2 SDS, P=0.001; IGFBP-3: -0.3+/-1.1 vs -1.0+/-1.1 SDS, P=0.02). Children with AML showed significantly higher IGFBP-2 (P=0.04) and significantly lower IGF-I (P=0.03) and IGFBP-3 (P=0.05) levels than children with ALL at day 100 after HSCT. We conclude that children with acute leukemia show important changes in the IGF system after HSCT. In particular, IGFBP-2 was significantly elevated at day 100 after HSCT. Increased IGFBP-2 and decreased IGF-I and IGFBP-3 may be associated with the increased proliferation rate of transplanted bone marrow.
