RESUMO
Two multicentre external quality assessments (EQA) for the molecular detection and genotyping of meticillin-resistant Staphylococcus aureus (MRSA) were arranged. Firstly, 11 samples containing various amounts of inactivated MRSA strains, meticillin-susceptible S. aureus (MSSA), meticillin-resistant coagulase-negative staphylococci (MRCoNS) or Escherichia coli were distributed to 82 laboratories. Samples containing 102 or 103 MRSA cells were correctly scored in only 16 and 46% of the datasets returned, respectively. Two of the used MSSA strains contained an SCCmec cassette lacking the mecA gene. There was a marked difference in the percentage of correct results for these two MSSA strains (37 and 39%) compared to the MSSA strain lacking the SCCmec cassette (88%). Secondly, a panel for MRSA genotyping, consisting of ten samples (two identical, three genetically related and five unique strains) was distributed to 19 laboratories. Seventy-three percent of the datasets recorded all samples correctly. Most pulsed-field gel electrophoresis (PFGE) protocols proved to be suboptimal, resulting in inferior resolution in the higher or lower fragment regions. The performance of molecular diagnostics for MRSA shows no significant changes since our first EQA in 2006. The first molecular typing results are encouraging. Both assessments indicate that programme expansion is required and that major performance discrepancies continue to exist.
Assuntos
Staphylococcus aureus Resistente à Meticilina/genética , Técnicas de Diagnóstico Molecular/métodos , Garantia da Qualidade dos Cuidados de Saúde/métodos , Infecções Estafilocócicas/microbiologia , Proteínas de Bactérias/genética , DNA Bacteriano/análise , Eletroforese em Gel de Campo Pulsado/métodos , Genótipo , Humanos , Proteínas de Ligação às Penicilinas , Staphylococcus aureus/genéticaRESUMO
The lens-specific intermediate filament (IF) proteins CP49 and filensin have been identified in a large number of evolutionary divergent species. In the chick lens both CP49 and filensin have been identified. Recently a unique variant of CP49, CP49ins has been identified. CP49ins contains an insertion of 49 amino acids in helix 1b giving it characteristics similar to the lamin-like cytoplasmic IF of invertebrates. The presence of this variant form in the chick lens poses some important questions about the co-assembly of the two CP49 forms and also the evolutionary relationship with invertebrate IF proteins.