RESUMO
AIMS: The aims of this study were to design, synthesize and to evaluate 2-hydroxy-3-phenylsulfanylmethyl-[1,4]-naphthoquinones against Gram-negative and Gram-positive bacterial strains, including methicillin-resistant Staphylococcus aureus (MRSA) and its biofilm, to probe for potential lead structures. METHODS AND RESULTS: Thirty-six new analogues were prepared with good yields using a simple, fast, operational three-procedure reaction and a thiol addition to an ο-quinone methide using microwave irradiation. All compounds were tested against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis ATCC 15290, Serratia marcescens ATCC 14756, Klebsiella pneumoniae ATCC 4352, Enterobacter cloacae ATCC 23355, Enterococcus faecalis ATCC 29212, S. aureus ATCC 25923, Staphylococcus simulans ATCC 27851, Staphylococcus epidermidis ATCC 12228 and a hospital strain of MRSA. Their antibacterial activity was determined using the disc diffusion method, revealing the activity of 19 compounds, mainly against Gram-positive strains. Interestingly, the minimal inhibitory concentration ranges detected for the hit molecules (32-128 µg ml-1 ) were within Clinical and Laboratory Standards Institute levels. Promisingly, compound 15 affected the MRSA strain, with a reduction of up to 50% in biofilm formation, which is better than vancomycin as biofilm forms a barrier against the antibiotic that avoids its action. CONCLUSIONS: After probing 36 naphthoquinones for a potential antibacterial lead structure against the bacterial biofilm, we found that compound 15 should be explored further and also should be structurally modified in the near future to test against Gram-negative strains. SIGNIFICANCE AND IMPACT OF THE STUDY: Since vancomycin is one of the last treatment options currently available, and it is unable to inhibit biofilm, the research of new antimicrobials is urgent. In this context, 2-hydroxy-3-phenylsulfanylmethyl-[1,4]-naphthoquinones proved to be a promising lead structure against MRSA and bacterial biofilm.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Naftoquinonas/farmacologia , Enterobacter cloacae , Enterococcus faecalis/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Naftoquinonas/química , Proteus mirabilis/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus/efeitos dos fármacos , VancomicinaRESUMO
Biofilm formed by Staphylococcus aureus is considered an important virulence trait in the pathogenesis of infections associated with implantable medical devices. Gene expression analyses are important strategies for determining the mechanisms involved in production and regulation of biofilm. Obtaining intact RNA preparations is the first and most critical step for these studies. In this article, we describe an optimized protocol for obtaining total RNA from sessile cells of S. aureus using the RNeasy Mini Kit. This method essentially consists of a few steps, as follows: 1) addition of acetone-ethanol to sessile cells, 2) lysis with lysostaphin at 37°C/10 min, 3) vigorous mixing, 4) three cycles of freezing and thawing, and 5) purification of the lysate in the RNeasy column. This simple pre-kit procedure yields high-quality total RNA from planktonic and sessile cells of S. aureus.
Assuntos
Técnicas Bacteriológicas/normas , Biofilmes/crescimento & desenvolvimento , RNA Bacteriano/isolamento & purificação , Staphylococcus aureus/genética , Técnicas Bacteriológicas/métodos , Eletroforese em Gel de Ágar , Proteínas Hemolisinas/metabolismo , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Controle de Qualidade , Reação em Cadeia da Polimerase em Tempo Real , Transcrição Reversa , Staphylococcus aureus/fisiologiaRESUMO
Biofilm formed by Staphylococcus aureus is considered an important virulence trait in the pathogenesis of infections associated with implantable medical devices. Gene expression analyses are important strategies for determining the mechanisms involved in production and regulation of biofilm. Obtaining intact RNA preparations is the first and most critical step for these studies. In this article, we describe an optimized protocol for obtaining total RNA from sessile cells of S. aureus using the RNeasy Mini Kit. This method essentially consists of a few steps, as follows: 1) addition of acetone-ethanol to sessile cells, 2) lysis with lysostaphin at 37°C/10 min, 3) vigorous mixing, 4) three cycles of freezing and thawing, and 5) purification of the lysate in the RNeasy column. This simple pre-kit procedure yields high-quality total RNA from planktonic and sessile cells of S. aureus.
Assuntos
Técnicas Bacteriológicas/normas , Biofilmes/crescimento & desenvolvimento , RNA Bacteriano/isolamento & purificação , Staphylococcus aureus/genética , Técnicas Bacteriológicas/métodos , Eletroforese em Gel de Ágar , Proteínas Hemolisinas/metabolismo , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Controle de Qualidade , Reação em Cadeia da Polimerase em Tempo Real , Transcrição Reversa , Staphylococcus aureus/fisiologiaRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) isolates genetically related to the CA-MRSA clone MW2/USA400 (ST1-SCCmecIV lineage) from the United States have emerged in hospitals in Rio de Janeiro and are associated with nosocomial bloodstream infections. To understand the virulence mechanisms involved in the adaptability of ST1 isolates as a hospital pathogen in Rio de Janeiro, we compared the virulence traits and fitness properties of the Brazilian isolates with those displayed by the CA-MRSA isolates from the United States. Similar to the USA400 from the United States, all the Brazilian isolates tested carried the genes encoding SEH and LukDE. In contrast, none of the Brazilian isolates carried the lukSF PVL, sea, sec, and sek genes. Competition experiments in mice demonstrated a significant increase in the fitness for the CA-MRSA isolates MW2 and USA400-0051 from the United States compared to other isolates. In the foreign body animal model, 83 % more North-American bacterial cells were recovered compared to the Brazilian ST1 isolates. Differences in gene expression of important virulence factors were detected. Transcription of rnaIII and psmα3 was increased about two-fold in the isolates from the United States, and sasG about two-fold in the Brazilian isolates. Thus, it is possible that the virulence attenuation observed among the Brazilian hospital isolates, associated with the acquisition of multiple resistant determinants, are consequences of microevolutionary events that contributed to the necessary fitness adjustment of this lineage, allowing a typically community-acquired MRSA (MW2/USA400) to emerge as a successful hospital pathogen (Brazilian ST1-SCCmecIV).
Assuntos
Infecções Comunitárias Adquiridas/microbiologia , Infecção Hospitalar/microbiologia , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/fisiologia , Infecções Estafilocócicas/microbiologia , Fatores de Virulência/genética , Animais , Evolução Biológica , Brasil , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Genes Bacterianos , Genótipo , Humanos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Camundongos , Estados Unidos , VirulênciaRESUMO
In this study, genotyping techniques including staphylococcal chromosomal cassette mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and restriction-modification tests were used to compare the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered at two times within a 10-year interval (1998 and 2008) from a tertiary Brazilian hospital. In addition, the antimicrobial susceptibility profiles were analyzed. All 48 MRSA isolates from 1998 and 85.7% from 2008 (48/56 isolates) displayed multidrug-resistance phenotypes and SCCmec III. All but one of the 13 representative SCCmec III isolates belonged to CC8 and had PFGE patterns similar to that of the BMB9393 strain (Brazilian epidemic clone of MRSA; BEC). In 2008, we found an increased susceptibility to rifampicin and chloramphenicol among the SCCmec III isolates. In addition, we detected the entrance of diverse international MRSA lineages susceptible to trimethoprim-sulfamethoxazole (SXT), almost all belonging to CC5. These non-SCCmec III isolates were related to the USA 300 (ST8-SCCmec IV; PFGE-type B), USA 800 (ST5-SCCmec IV; subtype D1), USA 100 (ST5-SCCmec II; subtype D2), and EMRSA-3/Cordobes (ST5-SCCmec I, type C) clones. To the best of our knowledge, this is the first report of the emergence of isolates genetically related to the EMRSA-3/Cordobes clone in southeast Brazil. In this regard, these isolates were the most common non-SCCmec III MRSA in our institution, accounting for 8.9% of all isolates recovered in 2008. Thus, despite the supremacy of BEC isolates in our country, significant changes may occur in local MRSA epidemiology, with possible consequences for the rationality of MRSA empiric therapy.
Assuntos
Humanos , Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Brasil , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Fenótipo , Fatores de TempoRESUMO
In this study, genotyping techniques including staphylococcal chromosomal cassette mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and restriction-modification tests were used to compare the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered at two times within a 10-year interval (1998 and 2008) from a tertiary Brazilian hospital. In addition, the antimicrobial susceptibility profiles were analyzed. All 48 MRSA isolates from 1998 and 85.7% from 2008 (48/56 isolates) displayed multidrug-resistance phenotypes and SCCmec III. All but one of the 13 representative SCCmec III isolates belonged to CC8 and had PFGE patterns similar to that of the BMB9393 strain (Brazilian epidemic clone of MRSA; BEC). In 2008, we found an increased susceptibility to rifampicin and chloramphenicol among the SCCmec III isolates. In addition, we detected the entrance of diverse international MRSA lineages susceptible to trimethoprim-sulfamethoxazole (SXT), almost all belonging to CC5. These non-SCCmec III isolates were related to the USA 300 (ST8-SCCmec IV; PFGE-type B), USA 800 (ST5-SCCmec IV; subtype D1), USA 100 (ST5-SCCmec II; subtype D2), and EMRSA-3/Cordobes (ST5-SCCmec I, type C) clones. To the best of our knowledge, this is the first report of the emergence of isolates genetically related to the EMRSA-3/Cordobes clone in southeast Brazil. In this regard, these isolates were the most common non-SCCmec III MRSA in our institution, accounting for 8.9% of all isolates recovered in 2008. Thus, despite the supremacy of BEC isolates in our country, significant changes may occur in local MRSA epidemiology, with possible consequences for the rationality of MRSA empiric therapy.
Assuntos
Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Brasil , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Fenótipo , Fatores de TempoRESUMO
Over the last years, investigations on the increase of platinum (Pt), palladium (Pd), and rhodium (Rh) levels in urban environments of big cities all over the world - especially to catalytic converters emissions - have been grown up enormously. São Paulo City is the 6th largest megacity in the world having about 20 million inhabitants and an ever increasing seven million motor vehicle fleet. In spite of this, there has never been an investigation regarding Pt, Pd, and Rh levels in the city. In the present study, Pt, Pd, and Rh concentrations were determined in soils adjacent to seven main high-density traffic avenues in the metropolitan region of São Paulo City. Inductively coupled plasma mass spectrometry was employed - after ultrasound-assisted aqua regia leaching - as analytical technigue. The results showed concentration levels up to 378 ng g(-1) for Pd, 208 ng g(-1) for Pt, and 0.2 to 45 ng g(-1) for Rh. These levels are much higher than those considered for the geochemical background of soils, indicating a catalytic converter source. Due to the different Pt/Pd/Rh ratio in Brazilian automobile catalytic converters, lower levels of Pt/Pd ratios compared with other similar studies were observed. The obtained results are the first data for monitoring Pt, Pd, and Rh pollution in São Paulo City soils.
Assuntos
Monitoramento Ambiental , Paládio/análise , Platina/análise , Ródio/análise , Poluentes do Solo/análise , Brasil , Cidades , Humanos , Veículos Automotores , Solo/químicaRESUMO
In this study, we associated the restriction modification (RM) tests to the polymerase chain reaction (PCR) detection of molecular markers (SCCmec III, seh, agr II-SCCmec IV, and lukSF) for revealing the main methicillin-resistant Staphylococcus aureus (MRSA) clones circulating in Brazil. This simple and rapid approach allowed a precise classification of the MRSA analyzed when compared with pulsed-field gel electrophoresis (PFGE) data.
Assuntos
Enzimas de Restrição-Modificação do DNA , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Tipagem Molecular/métodos , Reação em Cadeia da Polimerase/métodos , Infecções Estafilocócicas/microbiologia , Brasil , Análise por Conglomerados , Eletroforese em Gel de Campo Pulsado , Humanos , Staphylococcus aureus Resistente à Meticilina/genéticaRESUMO
The values of k(0) and Q(0) for (64)Zn(n,γ)(65)Zn and (68)Zn(n,γ)(69m)Zn reactions were determined experimentally. The irradiations were performed near the core of the IEA-R1 3.5MW nuclear research reactor of the Nuclear and Energy Research Institute - IPEN-CNEN/SP, in São Paulo, Brazil. The results for the neutron field parameters f and α were 49.7(19) and -1.1(31)×10(-3), respectively. The resulting values of k(0) and Q(0) for (64)Zn(n,γ)(65)Zn reaction were 5.63(8)×10(-3) and 1.69(6), respectively, and the corresponding values for (68)Zn(n,γ)(69m)Zn reaction were 4.00(6)×10(-4) and 2.34(4), respectively. These results were compared with the literature.
RESUMO
We report on an experimental study of the structures presented by urethane/urea elastomeric films without and with ferromagnetic nanoparticles incorporated. The study is made by using the X-ray diffraction, nuclear magnetic resonance (NMR), optical, atomic and magnetic force (MFM) microscopy techniques, and mechanical assays. The structure of the elastomeric matrix is characterized by a distance of 0.46 nm between neighboring molecular segments, almost independent on the stretching applied. The shear casting performed in order to obtain the elastomeric films tends to orient the molecules parallel to the flow direction thus introducing anisotropy in the molecular network which is reflected on the values obtained for the orientational order parameter and its increase for the stretched films. In the case of nanoparticles-doped samples, the structure remains nearly unchanged although the local order parameter is clearly larger for the undoped films. NMR experiments evidence modifications in the molecular network local ordering. Micrometer size clusters were observed by MFM for even small concentration of magnetic particles.
Assuntos
Elastômeros/química , Ferro/química , Nanopartículas Metálicas/química , Ureia/química , Uretana/química , Espectroscopia de Ressonância Magnética , Microscopia de Força Atômica , Tamanho da Partícula , Espalhamento a Baixo Ângulo , Propriedades de Superfície , Difração de Raios XRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is a major agent of hospital infections worldwide. In Brazil, a multiresistant MRSA lineage (ST239-SCCmecIIIA), the so-called Brazilian epidemic clone (BEC), has predominated in all regions. However, an increase in nosocomial infections caused by non-multiresistant MRSA clones has recently been observed. In the present study, 45 clinical isolates of MRSA obtained from a university hospital located in Natal city, Brazil, were identified by standard laboratory methods and molecularly characterized using staphylococcal chromosome cassette mec (SCCmec) typing and pulsed-field gel electrophoresis. Antimicrobial susceptibility testing was carried out using CLSI methods. The MRSA isolates studied displayed a total of 8 different pulsed-field gel electrophoresis patterns (types A to H) with predominance (73 percent) of pattern A (BEC-related). However, MRSA harboring SCCmec type IV were also identified, 3 (7 percent) of which were genetically related to the pediatric clone - USA800 (ST5-SCCmecIV). In addition, we found a considerable genetic diversity within BEC isolates. MRSA displaying SCCmecIV are frequently susceptible to the majority of non-β-lactam antibiotics. However, emergence of multiresistant variants of USA800 was detected.
Assuntos
Humanos , Variação Genética/genética , Staphylococcus aureus Resistente à Meticilina/genética , Antibacterianos , Técnicas de Tipagem Bacteriana , Brasil , DNA Bacteriano/genética , Genótipo , Hospitais Universitários , Testes de Sensibilidade Microbiana , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificaçãoRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is a major agent of hospital infections worldwide. In Brazil, a multiresistant MRSA lineage (ST239-SCCmecIIIA), the so-called Brazilian epidemic clone (BEC), has predominated in all regions. However, an increase in nosocomial infections caused by non-multiresistant MRSA clones has recently been observed. In the present study, 45 clinical isolates of MRSA obtained from a university hospital located in Natal city, Brazil, were identified by standard laboratory methods and molecularly characterized using staphylococcal chromosome cassette mec (SCCmec) typing and pulsed-field gel electrophoresis. Antimicrobial susceptibility testing was carried out using CLSI methods. The MRSA isolates studied displayed a total of 8 different pulsed-field gel electrophoresis patterns (types A to H) with predominance (73%) of pattern A (BEC-related). However, MRSA harboring SCCmec type IV were also identified, 3 (7%) of which were genetically related to the pediatric clone--USA800 (ST5-SCCmecIV). In addition, we found a considerable genetic diversity within BEC isolates. MRSA displaying SCCmecIV are frequently susceptible to the majority of non-beta-lactam antibiotics. However, emergence of multiresistant variants of USA800 was detected.
Assuntos
Variação Genética/genética , Staphylococcus aureus Resistente à Meticilina/genética , Antibacterianos , Técnicas de Tipagem Bacteriana , Brasil , DNA Bacteriano/genética , Genótipo , Hospitais Universitários , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade MicrobianaRESUMO
Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emergent pathogen in Brazil. However, there are no data on the prevalence of CA-MRSA. We report here the first well-characterized case of severe life-threatening CA-MRSA infection in a child living in Rio de Janeiro city. The patient had many complications including hematogenous osteomyelitis and involvement of multiple sites requiring drainage of soft-tissue abscess, and pleural and pericardial empyema. The MRSA isolates recovered were genotyped using PFGE, SCCmec typing and multilocus sequence typing. Disk diffusion tests were performed following Clinical and Laboratory Standards Institute recommendations. In addition, the presence of Panton-Valentine leukocidin (PVL) was assessed by PCR amplification, using specific primers for lukF-pv (encoding for the F subunit of the PVL). The bacterial isolates were related to the ST30-SCCmecIV lineage (Oceania Southwest Pacific clone), a PVL producer CA-MRSA previously detected in Porto Alegre, RS, Brazil. Also, the isolates analyzed were susceptible to all non-â-lactam antibiotics tested. The present report demonstrates that disseminated CA-MRSA disease is also occurring in Rio de Janeiro. Thus, the empirical treatment of moderate or severe infections suspected of being associated with CA-MRSA needs to be reviewed in order to allow prompt initiation of an effective therapy that also covers these microorganisms.
Assuntos
Criança , Feminino , Humanos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/microbiologia , Técnicas de Tipagem Bacteriana , Brasil/epidemiologia , Infecções Comunitárias Adquiridas/diagnóstico , Infecções Comunitárias Adquiridas/microbiologia , Testes de Sensibilidade Microbiana , Índice de Gravidade de Doença , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/epidemiologiaRESUMO
Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emergent pathogen in Brazil. However, there are no data on the prevalence of CA-MRSA. We report here the first well-characterized case of severe life-threatening CA-MRSA infection in a child living in Rio de Janeiro city. The patient had many complications including hematogenous osteomyelitis and involvement of multiple sites requiring drainage of soft-tissue abscess, and pleural and pericardial empyema. The MRSA isolates recovered were genotyped using PFGE, SCCmec typing and multilocus sequence typing. Disk diffusion tests were performed following Clinical and Laboratory Standards Institute recommendations. In addition, the presence of Panton-Valentine leukocidin (PVL) was assessed by PCR amplification, using specific primers for lukF-pv (encoding for the F subunit of the PVL). The bacterial isolates were related to the ST30-SCCmecIV lineage (Oceania Southwest Pacific clone), a PVL producer CA-MRSA previously detected in Porto Alegre, RS, Brazil. Also, the isolates analyzed were susceptible to all non-beta-lactam antibiotics tested. The present report demonstrates that disseminated CA-MRSA disease is also occurring in Rio de Janeiro. Thus, the empirical treatment of moderate or severe infections suspected of being associated with CA-MRSA needs to be reviewed in order to allow prompt initiation of an effective therapy that also covers these microorganisms.
Assuntos
Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/microbiologia , Técnicas de Tipagem Bacteriana , Brasil/epidemiologia , Criança , Infecções Comunitárias Adquiridas/diagnóstico , Infecções Comunitárias Adquiridas/microbiologia , Feminino , Humanos , Testes de Sensibilidade Microbiana , Índice de Gravidade de Doença , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/epidemiologiaRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial agent of biopolymer-associated infections, and isolates of S. aureus can produce different virulence factors, including potent toxins. The biofilm formation and accumulation by certain international MRSA lineages were analysed, and the toxic shock syndrome-associated genes (tst, seb and sec) among these isolates were assessed. In addition, the presence of lukF-pv (encoding the F-subunit of Panton-Valentine leukocidin (PVL)) was investigated. Most of the MRSA isolates tested were capable of forming biofilm on polystyrene surfaces, but lacked the superantigen toxin genes that were tested. PVL was rarely detected among the hospital isolates analysed.
Assuntos
Biofilmes/crescimento & desenvolvimento , Infecções Comunitárias Adquiridas/microbiologia , Infecção Hospitalar/microbiologia , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/fisiologia , Infecções Estafilocócicas/microbiologia , Fatores de Virulência/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Enterotoxinas/genética , Humanos , Leucocidinas/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Poliestirenos , Superantígenos/genéticaRESUMO
An increasing incidence of nosocomial infections caused by non-multiresistant methicillin-resistant Staphylococcus aureus (nMMRSA) has been reported worldwide. The present study genotyped nMMRSA isolates obtained from hospitals in two cities in Brazil. The hospital isolates displayed pulsed-field gel electrophoresis (PFGE) patterns that were similar to those of the USA100 (ST5-SCCmecII) and USA 800 (ST5-SCCmecIV) strains, which are related to the New York/Japan and paediatric clones, respectively. Carriage of SCCmecIV and the classification by multilocus sequence typing (MLST) of a representative of this PFGE pattern in clonal complex 5 (CC5) confirmed the genetic relationship of the Brazilian isolates with USA800. The USA800-related Brazilian isolates were responsible for severe nosocomial infections in compromised adults and elderly patients in Brazil. A higher growth rate, an ability to form biofilm on inert polystyrene surfaces and the presence of the egc locus may have contributed, at least in part, to the fitness of these organisms as global nosocomial pathogens.
Assuntos
Infecção Hospitalar/microbiologia , Resistência a Meticilina , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Técnicas de Tipagem Bacteriana , Biofilmes/crescimento & desenvolvimento , Brasil/epidemiologia , Criança , Pré-Escolar , Infecção Hospitalar/epidemiologia , Impressões Digitais de DNA , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Humanos , Incidência , Pessoa de Meia-Idade , Epidemiologia Molecular , Análise de Sequência de DNA , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimentoRESUMO
Tillandsia usneoides L. is an epiphytic bromeliad plant able to absorb water and nutrients directly from the air. For this reason this species was selected to carry out a monitoring study of air pollution in the metropolitan region of São Paulo, Brazil. Five consecutive transplantation experiments (8 weeks each) were performed in 10 sites of the city, submitted to different sources of air pollution (industrial, vehicular), using plants collected from an unpolluted area. After exposure, trace metals were analyzed in the plant by instrumental neutron activation analysis. Traffic-related elements such as Zn and Ba presented high concentrations in exposure sites near to heavy traffic avenues (cars, buses and trucks) and may be associated to vehicular sources. For Zn and Co the highest contents were related to industrial zones and can be associated to the presence of anthropogenic emission sources. The rare earth elements, Fe and Rb, probably have soil particles as main source.
Assuntos
Poluentes Atmosféricos/análise , Metais/análise , Tillandsia/química , Bário/análise , Biomarcadores/análise , Brasil , Cidades , Cobalto/análise , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental/métodos , Indústrias , Ferro/análise , Análise de Ativação de Nêutrons/métodos , Medição de Risco/métodos , Rubídio/análise , Poluentes do Solo/análise , Emissões de Veículos/análise , Zinco/análiseRESUMO
OBJECTIVE: To study colonization with methicillin-resistant Staphylococcus aureus in a home care service during a 4-month period. DESIGN: Prospective study. SETTING: A home care service located in Rio de Janeiro, Brazil. PARTICIPANTS: Patients admitted to the home care service during this period, their household contacts, and health care workers (HCWs). METHODS: Swab specimens from the anterior nares were collected from each patient in the 3 groups at admission. Screening was repeated every 7 days. MRSA was detected using a mecA probe, and the clonality of isolates was evaluated by molecular methods, primarily pulsed-field gel electrophoresis. RESULTS: Of the 59 study patients, 9 (15.3%) had MRSA colonization detected; these cases of colonization were classified as imported. Only 1 (2.0%) of the 50 patients not colonized at admission became an MRSA carrier (this case of colonization was classified as autochthonous). Two (0.9%) of 224 household contacts and 16 (7.4%) of 217 HCWs had MRSA colonization. Cross-transmission from patient to HCW could be clearly demonstrated in 8 cases. The great majority of MRSA isolates belonged to the Brazilian epidemic clone. CONCLUSIONS: MRSA colonization was common in the home care service analyzed. The fact that the majority of MRSA isolates obtained were primarily of nosocomial origin (and belonged to the so-called Brazilian epidemic clone) substantiated our findings that all but 1 patient had already been colonized before admission to the home care service. Only cross-transmission from patients to healthcare workers could be verified. On the basis of these results, we believe that a control program built on admission screening of patients for detection of MRSA carriage could contribute to the overall quality of care.
Assuntos
Serviços de Assistência Domiciliar , Resistência a Meticilina , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/genética , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Portador Sadio/epidemiologia , Infecção Hospitalar/epidemiologia , Feminino , Humanos , Masculino , Estudos Prospectivos , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificaçãoRESUMO
Twenty isolates of group B streptococcus (GBS) were recovered from the milk of cows with bovine mastitis on three farms located in the south and south-east of Brazil between 1987 and 1988. These isolates were characterised by molecular methods and compared with a collection of 103 human GBS isolates from colonised and infected patients in the same region between 1980 and 2003. Some of the bovine isolates shared identical or similar pulsed-field gel electrophoresis (PFGE) patterns with a PFGE clone of human GBS type V. In addition, these bovine and human isolates also possessed the same ribotype. Multilocus sequence typing (MLST) of representative isolates confirmed the genetic relationship between the human and bovine GBS isolates with identical PFGE patterns, which clustered in the same ST-26 clonal complex. These data support the hypothesis that some bovine GBS strains are related closely to human isolates and may infect humans, or vice versa. Further comparative genomic analyses of GBS isolates from bovine and human origins are required to investigate this hypothesis further.
Assuntos
Mastite Bovina/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae/classificação , Streptococcus agalactiae/genética , Animais , Técnicas de Tipagem Bacteriana , Brasil , Bovinos , Eletroforese em Gel de Campo Pulsado , Feminino , Humanos , Ribotipagem , Análise de Sequência de DNA , Sorotipagem , Infecções Estreptocócicas/veterináriaRESUMO
The dating of fossil teeth of an ancient goat (Nesogoral melonii) using the electron spin resonance (ESR) technique is reported. This animal was found in the fossiliferous site at Orosei (Nuoro, Sardinia, Italy) and was endemic in the region. Molar teeth were cleaned and enamel was completely removed from dentine. Enamel was irradiated with a 60Co gamma source and measured with an ESR spectrometer (X-band) to obtain the signal vs. dose curve and fitted with an exponential function. The archeological dose obtained by the fitting was 211 +/- 34 Gy. Uranium and thorium concentrations were determined by neutron activation analysis. With the software ROSY the age estimates were 195 +/- 30 ky for early uptake, 247 +/- 40 ky for linear uptake and 243 +/- 40 ky for a combination of uptake processes.