RESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) carrying SCCmec type IV has emerged in hospitals worldwide. The aim of this study was to evaluate phenotypic and molecular characteristics of antimicrobial resistance in MRSA SCCmec IV isolates, presenting different genetic backgrounds, isolated from hospitals in Rio de Janeiro. The antimicrobial resistance of 128 S. aureus type IV isolates from 11 hospitals was characterized by the disk diffusion test and minimum inhibitory concentration (MIC) test. Mutations in parC gene, which encodes ciprofloxacin resistance, and genes associated with macrolide-lincosamide-streptogramin B (MLSb) resistance were also investigated. MRSA isolates belonging to USA400/ST1 (60 isolates), USA800/ST5 (40), USA1100/ST30 (13), and other 11 (15) lineages were mainly resistant to erythromycin (68%), ciprofloxacin (56%), and clindamycin (50%). The highest antimicrobial resistance rates were found among USA400 isolates (p < 0.05). The majority of them (90%) carried only the erm(C) gene and mainly presented two mutation types in the parC gene. The msr(A) gene was most frequently found among USA800 isolates (p < 0.05). Among MRSA type IV isolates from Rio de Janeiro hospitals, multiresistance, including mutations in parC gene, was associated to the USA400/ST1, while the msr(A) gene was associated with USA800/ST5 isolates, highlighting that these lineages could have more potential to persist in a hospital environment.
Assuntos
DNA Topoisomerase IV/genética , Farmacorresistência Bacteriana Múltipla/genética , Regulação Bacteriana da Expressão Gênica , Staphylococcus aureus Resistente à Meticilina/genética , Metionina Sulfóxido Redutases/genética , Metiltransferases/genética , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , Brasil/epidemiologia , DNA Topoisomerase IV/metabolismo , Hospitais , Humanos , Lincosamidas/farmacologia , Macrolídeos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Metionina Sulfóxido Redutases/metabolismo , Metiltransferases/metabolismo , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Mutação , Quinolonas/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Estreptogramina B/farmacologiaRESUMO
Staphylococcus lugdunensis is a rare cause of severe infections and clinical manifestations are similar to those related to S. aureus infection. We describe a hospital-acquired bacteremia due to methicillin-resistant Staphylococcus lugdunensis, misidentified as methicillin-resistant S. aureus. The oxacillin MIC was 16 µg/mL and the mecA gene and SCCmec type V were determined by PCR. Although treatment had been appropriated, the patient died after rapid progressive respiratory failure and another nosocomial sepsis. It is important not only to identify S. lugdunensis in view of its clinical course, but also to determine its susceptibility to oxacillin by detecting the mecA gene or its product.
Assuntos
Idoso , Feminino , Humanos , Bacteriemia/microbiologia , Infecção Hospitalar/microbiologia , Resistência a Meticilina/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus lugdunensis/genética , Antibacterianos/farmacologia , Bacteriemia/diagnóstico , Proteínas de Bactérias/genética , Infecção Hospitalar/diagnóstico , Staphylococcus aureus Resistente à Meticilina , Resistência a Meticilina/efeitos dos fármacos , Oxacilina/farmacologia , Infecções Estafilocócicas/diagnóstico , Staphylococcus lugdunensis/efeitos dos fármacosRESUMO
Carbapenemase production is an important mechanism of carbapenem resistance among nonfermentative Gram-negative isolates. This study aimed to report the detection of blaOXA-58 gene in multiresistant clinical isolates of Acinetobacter baumannii recovered from inpatients in a public hospital. Polymerase chain reaction tests were performed to detect the blaOXA-23-like, blaOXA-24-like, blaOXA-58-like and blaOXA-51-like genes. The blaOXA-58 and blaOXA-23 genes were detected in one and three isolates, respectively. Sequencing of the blaOXA-58-like amplicon revealed 100 percent identity with the A. baumannii blaOXA-58 gene listed in the GenBank database. This is the first report of an OXA-58-producing A. baumannii isolate in Rio de Janeiro, Brazil.
Assuntos
Humanos , Acinetobacter baumannii , beta-Lactamases , Infecções por Acinetobacter , Acinetobacter baumannii , Acinetobacter baumannii/enzimologia , Antibacterianos , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Farmacorresistência Bacteriana Múltipla , Reação em Cadeia da PolimeraseRESUMO
INTRODUÇÃO: O gênero Staphylococcus é de grande importância devido a sua alta prevalência em infecções hospitalares e por apresentar taxas elevadas de resistência a oxacilina e a outros antimicrobianos. Assim, a avaliação da acurácia dos métodos fenotípicos usados para determinação do perfil de suscetibilidade a antimicrobianos é essencial para garantir a escolha da terapia mais adequada. MÉTODOS: Foram usadas 114 amostras de Staphylococcus sp (53 S. aureus e 61 SCN) na avaliação da acurácia dos métodos de difusão de disco, microdiluição em agar, ágar triagem oxacilina e sistema automatizado em comparação com a PCR para verificação da resistência a oxacilina. RESULTADOS: O gene mecA foi detectado em 48 (42,1 por cento) amostras e 27 (23,7 por cento) amostras apresentaram discrepância de resultados em pelo menos um dos métodos (74,1 por cento SCN, 25,9 por cento S. aureus). Para S. aureus, com exceção do Microscan Walkaway, todos os métodos apresentaram 100 por cento de especificidade e sensibilidade. Já para os SCN, o sistema automatizado e o disco de cefoxitina apresentaram menor acurácia. CONCLUSÕES: O uso de dois métodos deve ser a melhor opção para a melhora da acurácia, principalmente quando o laboratório de diagnóstico utiliza somente sistema automatizado ou teste de difusão do disco de oxacilina. A associação destes métodos com outros apresentaram praticamente 100 por cento de sensibilidade e especificidade em nosso estudo.
INTRODUCTION: The genus Staphylococcus is of great importance because of its high prevalence in hospital infections and because it presents high rates of resistance to oxacillin and other antimicrobials. Thus, evaluation of the accuracy of the phenotypic methods that are used to determine the profile of antimicrobial resistance is essential to ensure that the most appropriate therapy is chosen. METHODS: One hundred and fourteen strains of Staphylococcus sp (53 S. aureus and 61 CNS) were used to evaluate the accuracy of the methods of disk diffusion, agar microdilution, oxacillin screening agar and automated systems, in comparison with PCR for investigating resistance to oxacillin. RESULTS: The mecA gene was detected in 48 strains (42.1 percent), and 27 strains (23.7 percent) showed discrepant results in at least one of the methods (74.1 percent of CNS, 25.9 percent of S. aureus). For S. aureus, with the exception of the Microscan Walkaway, all the methods showed 100 percent specificity and sensitivity. In relation to CNS, the automated system and cefoxitin disk had lower accuracy. CONCLUSIONS: Use of two methods should be the best option for improved accuracy, especially when the diagnostic laboratory only uses an automated system or oxacillin disk diffusion test. Combination of these methods with others presented almost 100 percent sensitivity and specificity in our study.
Assuntos
Humanos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Cefoxitina/farmacologia , Testes de Sensibilidade Microbiana/métodos , Oxacilina/farmacologia , Staphylococcus/efeitos dos fármacos , Fenótipo , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade , Staphylococcus/isolamento & purificaçãoRESUMO
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococcus infections are a worldwide concern. Currently, these isolates have also shown resistance to vancomycin, the last therapy used in these cases. It has been observed that quinones and other related compounds exhibit antibacterial activity. This study evaluated the antibacterial activity, toxicity and in vivo dermal irritability of lapachol extracted from Tabebuia avellanedae and derivatives against methicillin-resistant staphylococcal isolates. In addition, its mechanism of action was also analyzed. METHODS: The compounds beta-lapachone, 3-hydroxy beta N lapachone and alpha-lapachone were tested to determine the MIC values against methicillin-resistant S. aureus, S. epidermidis and S. haemolyticus strains, being the two last ones hetero-resistant to vancomycin. Experiments of protein synthesis analysis to investigate the naphthoquinones action were assessed. In vitro toxicity to eukaryotic BSC-40 African Green Monkey Kidney cell cultures and in vivo primary dermal irritability in healthy rabbits were also performed. RESULTS: The compounds tested showed antibacterial activity (MICs of 8, 4/8 and 64/128 microg/mL to beta-lapachone, 3-hydroxy beta N lapachone and alpha-lapachone, respectively), but no bactericidal activity was observed (MBC > 512 microg/mL for all compounds). Although it has been observed toxic effect in eukaryotic cells, the compounds were shown to be atoxic when applied as topic preparations in healthy rabbits. No inhibition of proteins synthesis was observed. CONCLUSION: Our results suggest that quinones could be used in topic preparations against wound infections caused by staphylococci, after major investigation of the pharmacological properties of the compounds. Studies about the use of these compounds on tumoral cells could be carried on, due to their effect in eukaryotic cells metabolism.