RESUMO
We report the exceptional case of a severe intraocular Abiotrophia defectiva infection which developed after cataract surgery. Retinal involvement as a complication of A. defectiva endophthalmitis or the combination of acute-onset endophthalmitis with infiltrative keratitis caused by this pathogen has not been described. Moreover, our report represents the first documented ocular A. defectiva infection in Germany. A. defectiva was identified using biotyping and 16S ribosomal RNA gene sequence analysis. Despite vigorous antimicrobial therapy and repeated ocular surgery, visual outcome was poor.
Assuntos
Aerococcaceae/isolamento & purificação , Endoftalmite/microbiologia , Infecções por Bactérias Gram-Positivas/diagnóstico , Ceratite/microbiologia , Retinite/microbiologia , Aerococcaceae/classificação , Aerococcaceae/genética , Aerococcaceae/metabolismo , Idoso , Técnicas de Tipagem Bacteriana , Extração de Catarata/efeitos adversos , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Endoftalmite/complicações , Feminino , Alemanha , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Ceratite/complicações , RNA Ribossômico 16S/genética , Retinite/complicações , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Infecção da Ferida Cirúrgica/microbiologiaRESUMO
Staphylococcus epidermidis is a common pathogen in device-associated infections which is able to attach onto polymeric surfaces and develop multilayered biofilms. Attached S. epidermidis displays reduced susceptibility to antimicrobial agents. In this study we investigated the influence of ciprofloxacin and the group IV quinolones gatifloxacin, gemifloxacin, and moxifloxacin with the minimal attachment killing (MAK) assay. MAK concentrations were determined for three biofilm-positive wild-type strains and their isogenic biofilm-negative mutants Depending on strain and investigated quinolone, it was possible to distinguish between a heterogeneous MAK (MAKhetero), and a homogeneous resistance (MAKhomo) which corresponds to the model of a few persisting cells under antibiotic treatment. A lower MAKhomo was detected for the biofilm-negative mutants as well as for the corresponding wild-types for some of the tested quinolones, which seems to be a result of higher bacterial inocula, whereas the MAKhetero concentrations were comparable for mutants and wild-types for nearly all of the tested antibiotics and strains. These data indicate that biofilm formation is not necessary for persistence of attached S. epidermidis cells under treatment with quinolones and could explain therapeutic failure in foreign body-associated infections due to biofilm-negative S. epidermidis isolates. The individual resistance phenotypes of investigated strains indicate that the determination of MAK concentrations might help to predict the therapy outcome of foreign body-associated infections with both biofilm-positive and biofilm-negative S. epidermidis. Thus, the relatively high activity displayed by group IV quinolones against individual attached staphylococcal isolates indicates a possible treatment option with the respective quinolones for foreign body-associated infections due to these isolates.
Assuntos
Anti-Infecciosos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Farmacorresistência Bacteriana , Infecções Relacionadas à Prótese/tratamento farmacológico , Quinolonas/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus epidermidis/efeitos dos fármacos , Compostos Aza/farmacologia , Biofilmes/crescimento & desenvolvimento , Ciprofloxacina/farmacologia , Contagem de Colônia Microbiana , Relação Dose-Resposta a Droga , Fluoroquinolonas/farmacologia , Gatifloxacina , Gemifloxacina , Humanos , Testes de Sensibilidade Microbiana , Moxifloxacina , Mutação , Naftiridinas/farmacologia , Infecções Relacionadas à Prótese/microbiologia , Quinolinas/farmacologia , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/crescimento & desenvolvimentoRESUMO
Reporter gene systems are an invaluable tool for investigation of gene transcription activity in eukaryotes and prokaryotes. In order to analyze the temporal and spatial resolution of gene expression patterns in situ and for quantitatively investigating gene expression, the green fluorescent protein (GFP) appears to be especially useful. GFP has been broadly used in various bacterial species, however, there is only limited knowledge about key biological properties in S. epidermidis. Here, the crucial influence of different ribosomal binding sites (RBS) on gfpmut3.1 translation initiation in S. epidermidis 1457 is demonstrated. Only by using the RBS of the delta-hemolysin promoter, after 24 hours a strong fluorescence signal was obtained. The half-life of GFPmut3.1 in S. epidermidis 1457 was significantly shorter than in E. coli (7 h vs. 24 h). GFPmut3.1 derivatives with shorter half-lives (GFP(AAV) and GFP(ASV)) did not reach sufficient quantitative protein levels, and the resulting low fluorescence limits their use as reporter genes in S. epidermidis. This work provides fundamental insights into gfpmut3.1 expression in S. epidermidis and describes the crucial determinants of its biological behavior in this species. In general, this study underlines the need to accurately characterize key biological properties of this transcription marker in gram-positive hosts.
Assuntos
Fusão Gênica Artificial/métodos , Proteínas de Bactérias/biossíntese , Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/metabolismo , Staphylococcus epidermidis/genética , Proteínas de Bactérias/genética , Sítios de Ligação/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Fluorescência , Proteínas de Fluorescência Verde/genética , Meia-Vida , Proteínas Hemolisinas/genética , Regiões Promotoras Genéticas , Ribossomos/fisiologia , Staphylococcus epidermidis/metabolismo , Fatores de TempoRESUMO
Medical device-associated infections, most frequently caused by coagulase-negative staphylococci, especially Staphylococcus epidermidis, are of increasing importance in modern medicine. Regularly, antimicrobial therapy fails without removal of the implanted device. The most important factor in the pathogenesis of medical device-associated staphylococcal infections is the formation of adherent, multilayered bacterial biofilms. There is urgent need for an increased understanding of the functional factors involved in biofilm formation, the regulation of their expression, and the interaction of those potential virulence factors in device related infection with the host. Significant progress has been made in recent years which may ultimately lead to new rational approaches for better preventive, therapeutic, and diagnostic measures.
