RESUMEN
BACKGROUND: The use of indwelling medical devices is associated with a significant risk of infections by Staphylococcus aureus (S. aureus) which possesses a variety of virulence factors including many toxins and the ability to invade eukaryotic cells or to form biofilm on biotic and abiotic surfaces. The virulence factors above described are often related to proteins exposed on the bacterial surface. Blocking S. aureus colonization may reduce the incidence of invasive infectious diseases. Previously reports evaluated the anti-infective properties of serratiopeptidase (Spep), an extracellular metalloprotease produced by Serratia marcescens ATCC 21074 (E-15), in impairing virulence-related staphylococcal properties, such as attachment to inert surfaces and adhesion/invasion on eukaryotic cells. However, to date its mechanism of action is unknown. METHODS: Spep gene was PCR amplified and cloned into expression vector pET28b(+). The mutant EspepA was constructed from plasmid pET28b-Spep applying the one-step overlap extension PCR strategy. There sulting plasmids were costransformed in EcBL21(DE3) cells with the plasmid pRuW4inh1 harboring the Erwinia chrysanthemi secretion system. Bacterial pellets and supernatants were collected and analyzed by SDS-PAGE and zymography. The unambiguous identification and a detailed structure characterization of both the wild type and the mutant Spep were obtained by mass spectrometric analyses. The resultant supernatants sterilized by filtration were separately used to condition biofilm formation of S. aureus. Quantification was based on crystal violet method. RESULTS: In this work we constructed Spep mutant by substituting the glutamic acid in the catalytic site with a residue of alanine. In this manner we were able to evaluate the anti-biofilm activity of Spep mutant in absence of proteolytic activity. As expected, this mutant did not display protease activity but it retained its anti-biofilm properties, suggesting that this action is independent by enzymatic activity. CONCLUSIONS: New knowledge obtained from data reported in this paper calls attention to a novel mechanism of action of Spep. This protein could be developed as a potential "antipathogenic agent" capable to impair the ability of S. aureus to form biofilm on prostheses, catheters and medical devices, exploiting a mechanism different from the proteolytic activity.
Asunto(s)
Antiinfecciosos/metabolismo , Biopelículas/efectos de los fármacos , Metaloproteasas/metabolismo , Péptido Hidrolasas/metabolismo , Staphylococcus aureus/fisiología , Sustitución de Aminoácidos , Clonación Molecular , Escherichia coli/genética , Expresión Génica , Espectrometría de Masas , Metaloproteasas/química , Metaloproteasas/genética , Mutagénesis Sitio-Dirigida , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/aislamiento & purificación , Proteínas Mutantes/metabolismo , Péptido Hidrolasas/química , Péptido Hidrolasas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Staphylococcus aureus/efectos de los fármacosRESUMEN
Staphylococcus epidermidis is recognized as cause of biofilm-associated infections and interest in the development of new approaches for S. epidermidis biofilm treatment has increased. In a previous paper we reported that the supernatant of Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 presents an anti-biofilm activity against S. epidermidis and preliminary physico-chemical characterization of the supernatant suggested that this activity is due to a polysaccharide. In this work we further investigated the chemical nature of the anti-biofilm P. haloplanktis TAC125 molecule. The production of the molecule was evaluated in different conditions, and reported data demonstrated that it is produced in all P. haloplanktis TAC125 biofilm growth stages, also in minimal medium and at different temperatures. By using a surface coating assay, the surfactant nature of the anti-biofilm compound was excluded. Moreover, a purification procedure was set up and the analysis of an enriched fraction demonstrated that the anti-biofilm activity is not due to a polysaccharide molecule but that it is due to small hydrophobic molecules that likely work as signal. The enriched fraction was also used to evaluate the effect on S. epidermidis biofilm formation in dynamic condition by BioFlux system.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Pseudoalteromonas/fisiología , Staphylococcus epidermidis/fisiología , Regiones Antárticas , Polisacáridos/metabolismo , Pseudoalteromonas/metabolismo , Staphylococcus epidermidis/metabolismo , Tensoactivos/metabolismoRESUMEN
Betamethasone is an anti-inflammatory steroid drug used in cases of anaphylactic and allergic reactions, of Alzheimer and Addison diseases and in soft tissue injuries. It modulates gene expression for anti-inflammatory activity suppressing the immune system response. This latter effect might decrease the effectiveness of immune system response against microbial infections. Corticosteroids, in fact, mask some symptoms of infection and during their use superimposed infections may occur. Thus, the use of glucocorticoids in patients with sepsis remains extremely controversial. In this study we analyzed the in vitro effect of a commercial formulation of betamethasone (Bentelan) on several Gram positive and Gram negative bacteria of clinical relevance. It was found to be an inhibitor of the growth of most of the strains examined. Also the effect of betamethasone in combination with some classes of antibiotics was evaluated. Antibiotic-steroid combination therapy is, in such cases, superior to antibiotic-alone treatment to impair bacterial growths. Such effect was essentially not at all observable on Staphylococcus aureus or Coagulase Negative Staphylococci (CoNS).
Asunto(s)
Antibacterianos/farmacología , Betametasona/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Antibacterianos/administración & dosificación , Betametasona/administración & dosificación , Quimioterapia Combinada , Bacterias Gramnegativas/crecimiento & desarrollo , Bacterias Grampositivas/crecimiento & desarrollo , Pruebas de Sensibilidad MicrobianaRESUMEN
AIMS: The purpose of this study was to evaluate the antimicrobial efficacy of five different proteases belonging to two different families on Staphylococcus aureus and Staphylococcus epidermidis strains. METHODS AND RESULTS: We used three serine proteases and two metalloproteases in single species biofilm formation assays and in human cell invasion processes. Following each protease incubation with bacterial cells, surface protein patterns were analysed by SDS-PAGE and zymography. Some differently expressed proteins were identified by mass spectrometry. CONCLUSIONS: The effect of tested proteases on biofilm formation was not related to the protease category but was strain-dependent and was related to the biofilm formation capacity of each staphylococcal strain. Some proteases showed a nonspecific and indiscriminate effect on surface proteins, while others induced a discrete and reproducible action on protein profiles. SIGNIFICANCE AND IMPACT OF THE STUDY: The inhibition of the surface-related virulence factors is a promising avenue to overcome persistent infections caused by bacterial biofilms. To this end, we show here that proteases, in particular the metalloprotease serratiopeptidase, can interfere with adhesion and invasion of eukaryotic cells and biofilm formation in staphylococci and their use could represent a viable treatment for the development of novel combination therapies.
Asunto(s)
Biopelículas/efectos de los fármacos , Metaloproteasas/farmacología , Serina Proteasas/farmacología , Staphylococcus aureus/patogenicidad , Staphylococcus epidermidis/patogenicidad , Adhesión Bacteriana , Proteínas Bacterianas/análisis , Biopelículas/crecimiento & desarrollo , Genes Bacterianos , Células HeLa , Humanos , Proteínas de la Membrana/análisis , Péptido Hidrolasas/farmacología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética , Staphylococcus epidermidis/efectos de los fármacos , Staphylococcus epidermidis/genética , VirulenciaRESUMEN
Use of herbal plant remedies to treat infectious diseases is a common practice in many countries in traditional and alternative medicine. However to date there are only few antimicrobial agents derived from botanics. Based on microbiological screening tests of crude plant extracts we identified four compounds derived from Krameria, Aesculus hippocastanum and Chelidonium majus that showed a potentially interesting antimicrobial activity. In this work we present an in depth characterization of the inhibition activity of these pure compounds on the formation of biofilm of Staphylococcus aureus as well as of Staphylococcus epidermidis strains. We show that two of these compounds possess interesting potential to become active principles of new drugs.
Asunto(s)
Antibacterianos/química , Biopelículas/efectos de los fármacos , Productos Biológicos/química , Extractos Vegetales/farmacología , Plantas/química , Staphylococcus aureus/fisiología , Staphylococcus epidermidis/fisiología , Aesculus/química , Antibacterianos/farmacología , Productos Biológicos/farmacología , Chelidonium/química , Krameriaceae/química , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/metabolismo , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/químicaRESUMEN
Staphylococcus aureus and Staphylococcus epidermidis are the major cause of infections associated with implanted medical devices. Colonization on abiotic and biotic surfaces is often sustained by biofilm forming strains. Human natural defenses can interfere with this virulence factor. We investigated the effect of human apo-transferrin (apo-Tf, the iron-free form of transferrin, Tf) and holo-transferrin (holo-Tf, the iron-saturated form) on biofilm formation by CA-MRSA S. aureus USA300 type (ST8-IV) and S. epidermidis (a clinical isolate and ATCC 35984 strain). Furthermore S. aureus adhesion and invasion assays were performed in a eukaryotic cell line. A strong reduction in biofilm formation with both Tfs was obtained albeit at very different concentrations. In particular, the reduction in biofilm formation was higher with apo-Tf rather than obtained with holo-Tf. Furthermore, while S. aureus adhesion to eukaryotic cells was not appreciably affected, their invasion was highly inhibited in the presence of holo-Tf, and partially inhibited by the apo form. Our results suggest that Tfs could be used as antibacterial adjuvant therapy in infection sustained by staphylococci to strongly reduce their virulence related to adhesion and cellular invasion.
Asunto(s)
Adhesión Bacteriana/efectos de los fármacos , Staphylococcus/efectos de los fármacos , Transferrinas/farmacología , Biopelículas/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Células HeLa , Humanos , Isoformas de Proteínas/farmacología , Staphylococcus/fisiologíaRESUMEN
The main problem associated with artificial vascular devices is the risk of bacterial infections, mostly sustained by coagulase negative Staphylococci or Staphylococcus aureus. Many efforts have been made to identify materials refractory to bacterial adhesion. The aim of our study is to verify the antimicrobial properties of two kinds of vascular prosthesis to prevent early onset infections and the efficacy of the concomitant action of a systemic antibiotic treatment. Adult male Wistar rats were used. We subcutaneously implanted in four groups a silver-coated prosthesis fragment, and a rifampicin-soaked prosthesis fragment in the remaining four groups. We inoculated in the site of implant a high bacterial burden of S. aureus in four groups and a low burden in the remaining groups. Systemic levofloxacin was administered for seven days in four groups representing the two kinds of prosthesis; after 21 days the rats were sacrificed, prosthesis fragments were sonicated and the corresponding supernatants were plated for bacterial counts. The rifampicin-soaked prostheses explanted from rats treated with levofloxacin were sterile, regardless of the bacterial inoculum. In other groups some prostheses were colonized. In the experimental rat model used, the action of local and systemic antibiotic treatment was able to reduce colonisation of artificial prostheses.
Asunto(s)
Profilaxis Antibiótica , Prótesis Vascular/efectos adversos , Levofloxacino , Ofloxacino/uso terapéutico , Rifampin/farmacología , Plata/farmacología , Animales , Masculino , Infecciones Relacionadas con Prótesis/prevención & control , Ratas , Ratas Wistar , Infecciones Estafilocócicas/tratamiento farmacológicoRESUMEN
Herpes simplex virus infections are prevalent viral infections in humans. HSVs are also the most common cause of sporadic viral encephalitis (HSE). Magnetic resonance is the imaging method of choice for HSE because it provides the most sensitive method for detecting early lesions. The objective of this study is to set-up and in vitro test an experimental contrast agent specific for antigens present on HSV-infected cells, bound with a paramagnetic agent detectable by MR imaging. A selected anti-HSV HrFab was labelled with Alexa Fluor 488, 125I and Gd3+Cl6. In order to assess anti-HSV affinity and specificity, ELISA assays were performed. Vero cells infected with HSV strains were visualized by MRI using anti-HSV HrFab/Gd3+Cl6 complex. Results of the ELISA tests demonstrated that the anti-HSV HrFab labelled with Gd3+Cl6 showed similar affinity for the antigens while the 125I immunoconjugate showed reduced affinity. MRI confirmed high affinity and specificity of antibody for the detection of HSV infections.
Asunto(s)
Gadolinio , Herpesvirus Humano 1/aislamiento & purificación , Herpesvirus Humano 2/aislamiento & purificación , Imagen por Resonancia Magnética/métodos , Animales , Anticuerpos Antivirales/inmunología , Chlorocebus aethiops , Ensayo de Inmunoadsorción Enzimática , Aumento de la Imagen , Fragmentos Fab de Inmunoglobulinas/inmunología , Proteínas Recombinantes/inmunología , Células VeroRESUMEN
Unlike in Escherichia coli, in Salmonella enterica production of class B acid phosphatase (AphA) was detectable also in cells growing in the presence of glucose. Characterization of the aphA locus from a S. enterica ser. typhi strain showed that the aphA determinant is very similar to the E. coli homolog, and that its chromosomal location between the highly conserved tyrB and uvrA genes is retained. However, the aphA flanking regions were found to be markedly different in the two species, either between tyrB and aphA or between aphA and uvrA. The differences in the aphA 5'-flanking region, which in S. enterica is considerably shorter than in E. coli (183 vs. 1121 bp) and includes potential promoter sequences not present in E. coli, could be responsible for the different regulation of class B acid phosphatase observed in the two species.
Asunto(s)
Fosfatasa Ácida/genética , Mapeo Cromosómico , Proteínas de Escherichia coli , Escherichia coli/enzimología , Regulación Bacteriana de la Expresión Génica , Salmonella enterica/enzimología , Fosfatasa Ácida/biosíntesis , Adenosina Trifosfatasas/genética , Proteínas Bacterianas/genética , Secuencia de Bases , Cósmidos/genética , Proteínas de Unión al ADN/genética , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Genes Bacterianos , Glucosa/metabolismo , Datos de Secuencia Molecular , Mapeo Restrictivo , Salmonella enterica/genética , Salmonella enterica/crecimiento & desarrollo , Alineación de Secuencia , Análisis de Secuencia de ADNRESUMEN
Staphylococcus epidermidis is an important cause of catheter-associated infections, which are attributed to its ability to form a multilayered biofilm on polymeric surfaces. This ability depends, in part, on the activity of the icaADBC locus and the icaR gene, which are involved in the production of the polysaccharide intercellular adhesin (PIA) that is functionally necessary for cell-to-cell adhesion and biofilm accumulation. The present study determined: (1) the prevalence of the icaADBC operon in S. epidermidis isolates from catheter-related and other nosocomial infections; (2) the correlation between the presence of this operon, biofilm production and resistance to antibiotics; (3) the expression of ica genes and biofilm production; and (4) the genetic relatedness of the isolates. The results showed that icaRADBC was present in 45% of the isolates included in the study, and that such isolates were significantly more resistant to the main antibiotics tested than were ica-negative isolates. The presence of the entire cluster did not always correlate with biofilm production, determined under different culture conditions, but there was evidence to suggest a correlation when at least two genes (icaAD) were co-transcribed. Eight of 18 ica-positive isolates had the entire operon in the same restriction fragment after pulsed-field gel electrophoresis, but the isolates were not clonal. Estimation of genetic relatedness indicated that ica-positive S. epidermidis isolates belonged to different lineages, distributed in only one of two major clusters, with a genetic distance of c. 0.12.
Asunto(s)
Operón/genética , Staphylococcus epidermidis/genética , Adhesión Bacteriana/genética , Adhesión Bacteriana/fisiología , Biopelículas/crecimiento & desarrollo , Catéteres de Permanencia/microbiología , Farmacorresistencia Bacteriana/genética , Humanos , Operón/fisiología , Infecciones Estafilocócicas/microbiología , Staphylococcus epidermidis/fisiologíaRESUMEN
The Morganella morganii phoC gene, encoding a class A acid phosphatase, was used to generate gene fusions with modified amino-terminal moieties of the Escherichia coli lacZ gene carrying a multiple-cloning site flanked by phage-specific promoters and recognition sites for universal sequencing primers. The corresponding hybrid proteins retained a PhoC-like enzymatic activity which is easily detectable by a plate histochemical assay, rendering similar gene fusions potentially useful as targets for cloning-dependent insertional inactivation. Cloning experiments performed in plasmids carrying similar lacZ-phoC fusions confirmed their usefulness as cloning vectors for direct screening of recombinants. As compared to conventional lacZ alpha-complementation-based vectors, which can only be used in E. coli hosts carrying specific lacZ mutations, the lacZ-phoC fusion-based vectors can be used in combination with any E. coli host and require a less expensive histochemical assay for screening of recombinants, while retaining all the advantageous features that made the former so popular as general purpose cloning vehicles.
Asunto(s)
Fosfatasa Ácida/genética , Escherichia coli/genética , Genes Bacterianos , Mutagénesis Insercional , Fusión Artificial Génica , Clonación Molecular , ADN Recombinante , Escherichia coli/enzimología , Código Genético , Vectores Genéticos , Operón Lac , Plásmidos/genéticaRESUMEN
It has been clearly established that the inoculum size greatly affects the results of antibiotic susceptibility tests performed in both liquid and solid media in standard laboratory growth conditions (i.e. planktonic). Recently methods were developed to perform antibiotic susceptibility tests on bacteria growing in sessile conditions. The present study investigates the effect of the inoculum size on results obtained by these methods. Results show that the inoculum size does not affect tests performed in sessile conditions. A simple and reliable method is proposed to be applied to routine microbiological laboratory procedures.
Asunto(s)
Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana/métodos , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/crecimiento & desarrollo , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/crecimiento & desarrollo , Staphylococcus epidermidis/efectos de los fármacos , Staphylococcus epidermidis/crecimiento & desarrollo , Reproducibilidad de los ResultadosRESUMEN
The antibacterial activity of 6 antibiotics towards 10 gram-positive and 6 gram-negative glycocalyx-producing strains, has been evaluated by employing a method which partially simulates the in vivo colonization of prosthetic devices. The results showed that routine antibiotic sensitivity tests are not predictive about the response of the glycocalyx-embedded bacteria, and that prophylaxis may be useful with ofloxacin and clindamycin, before placing a prosthetic device. Once bacterial colonization had already occurred, however, none of the tested antibiotics was able to eradicate the sessile bacterial form. The minimum bactericidal concentration (MBC) values, indeed, were much higher than those determined on the planktonic form, and were much higher than serum and tissue levels that can be reached in vivo.
Asunto(s)
Antibacterianos/farmacología , Bacterias/metabolismo , Infecciones Bacterianas/metabolismo , Catéteres de Permanencia , Pruebas de Sensibilidad Microbiana , Prótesis e Implantes , Bacterias/efectos de los fármacos , Infecciones Bacterianas/tratamiento farmacológico , Membrana Celular/metabolismo , Pruebas de Sensibilidad Microbiana/métodosRESUMEN
A novel staining procedure to demonstrate glycocalyx production by clinical isolates is presented. The short times required, specificity and sensitivity suggest that the staining could be applied to routine in vitro diagnostic procedures.
Asunto(s)
Biopelículas , Glicoproteínas/aislamiento & purificación , Polisacáridos/aislamiento & purificación , Prótesis e Implantes/microbiología , Coloración y Etiquetado/métodos , Adhesión Bacteriana , Infecciones Bacterianas , Prótesis de la Rodilla/microbiología , Micrococcus luteus/crecimiento & desarrollo , Pseudomonas aeruginosa/crecimiento & desarrolloRESUMEN
AIM: Vascular dementia (VaD) is defined as a loss of cognitive function resulting from ischemic, hypoperfusive, or hemorrhagic brain lesions due to cerebrovascular disease or cardiovascular pathology. The main types of VaD are: Small Vessel Disease Dementia (sVAD), Large vessel disease dementia, hypoperfusive-ischemic dementia and hemorragic dementia. The sVAD is divided into two main categories: subcortical ischemic vascular dementia (SIVD) and cortical dementia. Currently, no drugs are approved for the treatment of VaD. This study aimed to determine whether rivastigmine, a second generation cholinesterase inhibitor with selectivity for the CNS, with capacity to inhibit both acetylcholinesterase (AChE) and butyryl-cholinesterase (BuChE), slows the rate of cognitive decline associated with VaD. METHODS: Study subjects were 27 male and 43 female outpatients aged 80.03±6.53 years, with Mini-Mental State Examination (MMSE) score ranging batween 22 and 12, affected by VaD. They were included in the study if they were undergoing pharmacological treatment with acetylsalicylic acid 100 mg for at least six months. Patients were divided into two groups: one group was treated with ASA 100 mg and rivastigmine patch 9.5 mg (Rivastigmine group), the other just with ASA 100 mg (ASA group). All patients were followed for 6 months, with a first evaluation (T0) and a second examination after six mounths of treatment (T1). RESULTS: Statistically data proved as the Rivastigmine group showed constant values at MMSE, compared with patients of the ASA group who experienced decline of their cognitive performances. The same result was found in CDR, ADL, GDS and NPI scales. It is remarkable to underline as Rivastigmine-treated patients had a mean improvement in GDS scales, in comparison with patients of the ASA group who showed a worsening of mood. CONCLUSION: Rivastigmine-therapy improves cognitive performance in elderly with SIVD.
Asunto(s)
Acetilcolinesterasa , Butirilcolinesterasa , Inhibidores de la Colinesterasa/uso terapéutico , Cognición/efectos de los fármacos , Demencia Vascular/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Fenilcarbamatos/uso terapéutico , Anciano , Anciano de 80 o más Años , Antiinflamatorios no Esteroideos/uso terapéutico , Aspirina/uso terapéutico , Demencia Vascular/clasificación , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Escala del Estado Mental , RivastigminaAsunto(s)
Antibacterianos/farmacología , Myxococcales/efectos de los fármacos , Procedimientos Ortopédicos/efectos adversos , Cefotaxima/farmacología , Clindamicina/farmacología , Ensayo de Unidades Formadoras de Colonias , Humanos , Imipenem/farmacología , Pruebas de Sensibilidad Microbiana , Miocamicina/farmacología , Myxococcales/aislamiento & purificación , Myxococcales/fisiología , Ofloxacino/farmacología , Complicaciones Posoperatorias/microbiologíaAsunto(s)
Antibacterianos/farmacología , Leucomicinas/farmacología , Animales , Antibacterianos/uso terapéutico , Bacterias/efectos de los fármacos , Infecciones Bacterianas/tratamiento farmacológico , Leucomicinas/uso terapéutico , Ratones , Pruebas de Sensibilidad Microbiana , Miocamicina , Peritonitis/tratamiento farmacológicoRESUMEN
BACKGROUND: In recent years, several reports have suggested, but never definitely demonstrated that dental units (DU) could be potential sources of viral cross-infections sustained by viral agents including HBV, HCV and HIV. This work aims at assessing the risk of HCV cross-infection by dental unit water lines (DUWLs). MATERIALS AND METHODS: Ten anti-HCV positive viremic patients were submitted to dental treatment on three different DU (one unit fully equipped to minimize viral contamination risk). A PCR method using primers for UTR and E2 regions was used to evaluate HCV RNA presence in DUWLs sprays. A modified RNA extraction protocol was developed to eliminate the risk of low sensibility due to the presence of inhibitors in saliva. Sequences obtained from E2 PCR products amplified from blood and oral fluids were analyzed and compared. RESULTS: Fluids collected from three different DU before treatment were always negative for the presence of HCV RNA; after treatment viral contamination was detected in six out of ten cases in conventional DU, in three out of ten cases on the reduced-retraction DU while was never detected in sprays taken from fully equipped DU. Comparison of E2 region sequences obtained from blood and DUWLs sprays showed identity in each patient. CONCLUSION: Here we demonstrate that fixed DUWLs and handpieces can be contaminated by viral agents and become a vehicle of cross-infection and that a specific online active decontamination system developed for both handpieces and fixed waterlines can eliminate this risk.
Asunto(s)
Infección Hospitalaria/prevención & control , Equipo Dental/virología , Contaminación de Equipos/prevención & control , Hepacivirus/aislamiento & purificación , Control de Infección Dental , Infección Hospitalaria/virología , Agua Dulce/virología , Hepacivirus/genética , Hepatitis C/prevención & control , Hepatitis C/transmisión , Hepatitis C/virología , Humanos , Proyectos PilotoRESUMEN
We found that nalidixic acid is a good inhibitor of conjugal transfer of R-plasmids and that related compounds show the same properties. We investigated recently synthetized quinolinic molecules. The inhibition was not due to bacterial activity of the compounds against donors, recipients or R transconjugants; in fact, the drug concentrations were twice or four times lower than the M.I.C. values. The new molecules showed a marked inhibitory effect in various R-mating experiments.
Asunto(s)
4-Quinolonas , Antibacterianos/farmacología , Antiinfecciosos , Conjugación Genética/efectos de los fármacos , Ácido Nalidíxico/farmacología , Quinolinas/farmacología , Quinolonas , Ciprofloxacina , Escherichia coli/efectos de los fármacos , Ácido Nalidíxico/análogos & derivados , NorfloxacinoRESUMEN
Among the different mechanisms of bacterial resistance to antimicrobial agents that have been studied, biofilm formation is one of the most widespread. This mechanism is frequently the cause of failure in the treatment of prosthetic device infections, and several attempts have been made to develop molecules and protocols that are able to inhibit biofilm-embedded bacteria. We present data suggesting the possibility that proteolytic enzymes could significantly enhance the activities of antibiotics against biofilms. Antibiotic susceptibility tests on both planktonic and sessile cultures, studies on the dynamics of colonization of 10 biofilm-forming isolates, and then bioluminescence and scanning electron microscopy under seven different experimental conditions showed that serratiopeptidase greatly enhances the activity of ofloxacin on sessile cultures and can inhibit biofilm formation.