RESUMO
We typed 600 methicillin-resistant Staphylococcus aureus (MRSA) isolates collected in 51 hospitals in the Rio de Janeiro, Brazil, metropolitan area during 2014-2017. We found that multiple new clonal complex (CC) 5 sequence types had replaced previously dominant MRSA lineages in hospitals. Whole-genome analysis of 208 isolates revealed an emerging sublineage of multidrug-resistant MRSA, sequence type 105, staphylococcal cassette chromosome mec II, spa t002, which we designated the Rio de Janeiro (RdJ) clone. Using molecular clock analysis, we hypothesized that this lineage began to expand in the Rio de Janeiro metropolitan area in 2009. Multivariate analysis supported an association between bloodstream infections and the CC5 lineage that includes the RdJ clone. Compared with other closely related isolates, representative isolates of the RdJ clone more effectively evaded immune function related to monocytic cells, as evidenced by decreased phagocytosis rate and increased numbers of viable unphagocytosed (free) bacteria after in vitro exposure to monocytes.
Assuntos
Bacteriemia , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Bacteriemia/epidemiologia , Brasil/epidemiologia , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Monócitos , Infecções Estafilocócicas/epidemiologiaRESUMO
Staphylococcus aureus is an important nosocomial and community-acquired pathogen. Hospital infections are frequently complicated by the ability of bacteria to form biofilms on different surfaces. The development of bacterial films on medical indwelling devices, such as prostheses, often requires surgical procedures to remove the contaminated implant. Indeed, biofilm formation on central endovenous catheters is a major cause of primary bacteraemia in hospitals. The modulation of virulence factors in S. aureus is orchestrated by a number of global regulators including agr RNAIII. To improve our understanding of the role of the agr quorum-sensing system in biofilm formation by S. aureus, we constructed a number of agr-null mutants, derived from contemporary clinical isolates. Analysis of these mutants indicates that agr has a significant impact on biofilm development for most of the isolates tested. Our data show that RNAIII can control both biofilm formation and accumulation. The agr effect included both up- and downregulation of biofilms, even for isolates within the same lineage, corroborating the hypothesis that the mechanisms involved in S. aureus biofilms are complex and probably multifactorial.
Assuntos
Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Glucose/metabolismo , RNA Bacteriano/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/fisiologia , Transativadores/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Staphylococcus aureus Resistente à Meticilina/fisiologia , Dados de Sequência Molecular , RNA Bacteriano/metabolismo , Alinhamento de Sequência , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/patogenicidade , Transativadores/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
O objetivo deste estudo foi avaliar a eficácia de quatro soluçöes comerciais de hipoclorito de sódio a 2-2,5 por cento em eliminar esporos de Bacillus subtilis sobre cones de "gutta-percha". Os produtos testados foram três marcas de água sanitária (Clorox, Q-Boa e Super Globo) e Virex. Os cones de "gutta-percha" contaminados com os esporos foram deixados em contato com as soluçöes por 1, 3, 5, 10 e 20 minutos. Os resultados demonstraram que todas as soluçöes testadas descontaminaram os cones após um minuto de contato
Assuntos
Guta-Percha , Hipoclorito de Sódio , Esporos Bacterianos , Esterilização , Desinfetantes de Equipamento Odontológico , Descontaminação/métodosRESUMO
Nosocomial infections are an important cause of morbidity and mortality all over the world. It has been shown that appropriate enviromental hygienic and disinfection practices can be very helpful to hospital infection control. The purpose of this study was to evaluate the bactericidal activity of some disinfectants against antibiotic-susceptible and antibiotic-resistant hospital bacterial isolates. The susceptibility of 27 clinical isolates to disinfectants and antibiotics was determined by the Association of Official Analytical Chemist's (AOAC). Use-Dilution method and by the Kirby-Bauer method, respectively. All strains tested were susceptible to sodium hypochlorite, glutaraldehyde and to the association quartenary ammonium - formaldehyde - ethyl alcohol disinfectants. However, the susceptibility of strains to phenol and to one quartenary ammonium compound was variable. Among twenty-one antibiotic-multiresistant strains (methicillin-resistant staphylococci, "Enterococcus" spp, "Pseudomonas aeruginosa", "Klebsiella pneumoniae", "Proteus mirabilis", "Enterobacter cloacae", "Serratia marcescens" and "Escherichia coli") eleven (52(per cent)) and eight (38(per cent)) strains were resistant to the quaternary ammonium and phenol compounds, respectively. Among six isolates that demonstrated susceptibility to antibiotics (staphylococci, "Enterococcus" spp., "P. mirabilis", "E. cloacae" and "E. coli") two strains (33(per cent)) showed resisance to these disinfectants. The results demosntrated the lack of correlation between antibiotic-susceptibility and susceptibility to disinfectants in hospital strains