RESUMO
Enterococcus faecalis is among the most resistant bacteria found in infected root canals. The demand for cutting-edge disinfection methods has rekindled research on photoinactivation with visible light. This study investigated the bactericidal activity of femtosecond laser irradiation against vancomycin-resistant Enterococcus faecalis V583 (VRE). The effect of parameters such as wavelength and energy density on the viability and growth kinetics of VRE was studied to design an optimized laser-based antimicrobial photoinactivation approach without any prior addition of exogenous photosensitizers. The most effective wavelengths were 430 nm and 435 nm at a fluence of 1000 J/cm2, causing a nearly 2-log reduction (98.6% and 98.3% inhibition, respectively) in viable bacterial counts. The colony-forming units and growth rate of the laser-treated cultures were progressively decreased as energy density or light dose increased at 445 nm but reached a limit at 1250 J/cm2. At a higher fluence of 2000 J/cm2, the efficacy was reduced due to a photobleaching phenomenon. Our results highlight the importance of optimizing laser exposure parameters, such as wavelength and fluence, in bacterial photoinactivation experiments. To our knowledge, this is the first study to report an optimized wavelength for the inactivation of VRE using visible femtosecond laser light.
Assuntos
Enterococcus faecalis , Enterococcus faecalis/efeitos da radiação , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecalis/efeitos dos fármacos , Humanos , Enterococos Resistentes à Vancomicina/efeitos da radiação , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Viabilidade Microbiana/efeitos da radiação , Lasers , Cinética , Resistência a VancomicinaRESUMO
Infections with enterococci are challenging to treat due to intrinsic resistance to several antibiotics. Especially vancomycin-resistant Enterococcus faecium and Enterococcus faecalis are of considerable concern with a limited number of efficacious therapeutics available. From an initial screening of 20 peptidomimetics, 11 stable peptide/ß-peptoid hybrids were found to have antibacterial activity against eight E. faecium and E. faecalis isolates. Microbiological characterization comprised determination of minimal inhibitory concentrations (MICs), probing of synergy with antibiotics in a checkerboard assay, time-kill studies, as well as assessment of membrane integrity. E. faecium isolates proved more susceptible than E. faecalis isolates, and no differences in susceptibility between the vancomycin-resistant (VRE) and -susceptible E. faecium isolates were observed. A test of three peptidomimetics (Ac-[hArg-ßNsce]6-NH2, Ac-[hArg-ßNsce-Lys-ßNspe]3-NH2 and Oct-[Lys-ßNspe]6-NH2) in combination with conventional antibiotics (vancomycin, gentamicin, ciprofloxacin, linezolid, rifampicin or azithromycin) revealed no synergy. The same three potent analogues were found to have a bactericidal effect with a membrane-disruptive mode of action. Peptidomimetics Ac-[hArg-ßNsce-Lys-ßNspe]3-NH2 and Oct-[Lys-ßNspe]6-NH2 with low MIC values (in the ranges 2-8 µg/mL and 4-16 µg/mL against E. faecium and E. faecalis, respectively) and displaying weak cytotoxic properties (i.e., <10% hemolysis at a ~100-fold higher concentration than their MICs; IC50 values of 73 and 41 µg/mL, respectively, against HepG2 cells) were identified as promising starting points for further optimization studies.
Assuntos
Antibacterianos , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecium/crescimento & desenvolvimento , Peptoides , Resistência a Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Antibacterianos/química , Antibacterianos/farmacologia , Peptoides/química , Peptoides/farmacologiaRESUMO
Vancomycin-resistant Enterococcus (VRE) is a leading cause of hospital-acquired infections and continues to spread despite widespread implementation of pathogen-targeted control guidelines. Commensal gut microbiota provide colonization resistance to VRE, but the role of gut microbiota in VRE acquisition in at-risk patients is unknown. To address this gap in our understanding, we performed a case-control study of gut microbiota in hospitalized patients who did (cases) and did not (controls) acquire VRE. We matched case subjects to control subjects by known risk factors and "time at risk," defined as the time elapsed between admission until positive VRE screen. We characterized gut bacterial communities using 16S rRNA gene amplicon sequencing of rectal swab specimens. We analyzed 236 samples from 59 matched case-control pairs. At baseline, case and control subjects did not differ in gut microbiota when measured by community diversity (P = 0.33) or composition (P = 0.30). After hospitalization, gut communities of cases and controls differed only in the abundance of the Enterococcus-containing operational taxonomic unit (OTU), with the gut microbiota of case subjects having more of this OTU than time-matched control subjects (P = 0.01). Otherwise, case and control communities after the time at risk did not differ in diversity (P = 0.33) or community structure (P = 0.12). Among patients who became VRE colonized, those having the Blautia-containing OTU on admission had lower Enterococcus relative abundance once colonized (P = 0.004). Our results demonstrate that the 16S profile of the gut microbiome does not predict VRE acquisition in hospitalized patients, likely due to rapid and profound microbiota change. The gut microbiome does not predict VRE acquisition, but it may be associated with Enterococcus expansion, suggesting that these should be considered two distinct processes.IMPORTANCE The Centers for Disease Control and Prevention estimates that VRE causes an estimated 54,000 infections and 539 million dollars in attributable health care costs annually. Despite improvements in hand washing, environmental cleaning, and antibiotic use, VRE is still prevalent in many hospitals. There is a pressing need to better understand the processes by which patients acquire VRE. Multiple lines of evidence suggest that intestinal microbiota may help some patients resist VRE acquisition. In this large case-control study, we compared the 16S profile of intestinal microbiota on admission in patients that did and did not subsequently acquire VRE. The 16S profile did not predict subsequent VRE acquisition, in part due to rapid and dramatic change in the gut microbiome following hospitalization. However, Blautia spp. present on admission predicted decreased Enterococcus abundance after VRE acquisition, and Lactobacillus spp. present on admission predicted Enterococcus dominance after VRE acquisition. Thus, VRE acquisition and domination may be distinct processes.
Assuntos
Enterococcus faecium/crescimento & desenvolvimento , Microbioma Gastrointestinal/fisiologia , RNA Ribossômico 16S/genética , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Antibacterianos/farmacologia , Fenômenos Fisiológicos Bacterianos , Estudos de Casos e Controles , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana , Enterococcus faecium/patogenicidade , Fezes/microbiologia , Feminino , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/prevenção & controle , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Vancomicina/farmacologia , Enterococos Resistentes à Vancomicina/genética , Enterococos Resistentes à Vancomicina/patogenicidadeRESUMO
Intestinal commensal bacteria can inhibit dense colonization of the gut by vancomycin-resistant Enterococcus faecium (VRE), a leading cause of hospital-acquired infections1,2. A four-strained consortium of commensal bacteria that contains Blautia producta BPSCSK can reverse antibiotic-induced susceptibility to VRE infection3. Here we show that BPSCSK reduces growth of VRE by secreting a lantibiotic that is similar to the nisin-A produced by Lactococcus lactis. Although the growth of VRE is inhibited by BPSCSK and L. lactis in vitro, only BPSCSK colonizes the colon and reduces VRE density in vivo. In comparison to nisin-A, the BPSCSK lantibiotic has reduced activity against intestinal commensal bacteria. In patients at high risk of VRE infection, high abundance of the lantibiotic gene is associated with reduced density of E. faecium. In germ-free mice transplanted with patient-derived faeces, resistance to VRE colonization correlates with abundance of the lantibiotic gene. Lantibiotic-producing commensal strains of the gastrointestinal tract reduce colonization by VRE and represent potential probiotic agents to re-establish resistance to VRE.
Assuntos
Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Enterococcus faecium/efeitos dos fármacos , Lactococcus lactis/metabolismo , Probióticos , Resistência a Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Animais , Antibacterianos/biossíntese , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bacteriocinas/genética , Bacteriocinas/isolamento & purificação , Enterococcus faecium/crescimento & desenvolvimento , Enterococcus faecium/isolamento & purificação , Fezes/microbiologia , Feminino , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/microbiologia , Vida Livre de Germes , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/crescimento & desenvolvimento , Humanos , Lactococcus lactis/química , Lactococcus lactis/crescimento & desenvolvimento , Lactococcus lactis/fisiologia , Camundongos , Testes de Sensibilidade Microbiana , Microbiota/genética , Nisina/química , Nisina/farmacologia , Simbiose/efeitos dos fármacos , Vancomicina/farmacologia , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/isolamento & purificaçãoRESUMO
Vancomycin-resistant Enterococcus (VRE) are highly antibiotic-resistant and readily transmissible pathogens that cause severe infections in hospitalized patients. We discovered that lithocholic acid (LCA), a secondary bile acid prevalent in the cecum and colon of mice and humans, impairs separation of growing VRE diplococci, causing the formation of long chains and increased biofilm formation. Divalent cations reversed this LCA-induced switch to chaining and biofilm formation. Experimental evolution in the presence of LCA yielded mutations in the essential two-component kinase yycG/walK and three-component response regulator liaR that locked VRE in diplococcal mode, impaired biofilm formation, and increased susceptibility to the antibiotic daptomycin. These mutant VRE strains were deficient in host colonization because of their inability to compete with intestinal microbiota. This morphotype switch presents a potential non-bactericidal therapeutic target that may help clear VRE from the intestines of dominated patients, as occurs frequently during hematopoietic stem cell transplantation.
Assuntos
Ácidos e Sais Biliares/metabolismo , Colo/microbiologia , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/crescimento & desenvolvimento , Infecções por Bactérias Gram-Positivas/microbiologia , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Animais , Portador Sadio/microbiologia , Camundongos , Virulência/efeitos dos fármacosRESUMO
Vancomycin-resistant Enterococcus (VRE) infection is a serious challenge for clinical management and there is no effective treatment at present. Fecal microbiota transplantation (FMT) and probiotic intervention have been shown to be promising approaches for reducing the colonization of certain pathogenic bacteria in the gastrointestinal tract, however, no such studies have been done on VRE. In this study, we evaluated the effect of FMT and two Lactobacillus strains (Y74 and HT121) on the colonization of VRE in a VRE-infection mouse model. We found that both Lactobacilli strains reduced VRE colonization rapidly. Fecal microbiota and colon mRNA expression analyses further showed that mice in FMT and the two Lactobacilli treatment groups restored their intestinal microbiota diversity faster than those in the phosphate buffer saline (PBS) treated group. Administration of Lactobacilli restored Firmicutes more quickly to the normal level, compared to FMT or PBS treatment, but restored Bacteroides to their normal level less quickly than FMT did. Furthermore, these treatments also had an impact on the relative abundance of intestinal microbiota composition from phylum to species level. RNA-seq showed that FMT treatment induced the expression of more genes in the colon, compared to the Lactobacilli treatment. Defense-related genes such as defensin α, Apoa1, and RegIII were down-regulated in both FMT and the two Lactobacilli treatment groups. Taken together, our findings indicate that both FMT and Lactobacilli treatments were effective in decreasing the colonization of VRE in the gut.
Assuntos
Antibiose , Portador Sadio/terapia , Trato Gastrointestinal/microbiologia , Infecções por Bactérias Gram-Positivas/terapia , Lactobacillus/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Animais , Modelos Animais de Doenças , Transplante de Microbiota Fecal/métodos , Camundongos , Resultado do TratamentoRESUMO
BACKGROUND: The transition from manual processing of patient samples to automated workflows in medical microbiology is challenging. Although automation enables microbiologists to evaluate all samples following the same incubation period, the essential incubation times have yet to be determined. We defined essential incubation times for detecting methicillin-resistant Staphylococcus aureus (MRSA), multi-drug resistant gram-negative bacteria (MDRGN), and vancomycin-resistant enterococci (VRE). METHODS: We monitored the growth kinetics of MRSA, MDRGN, and VRE between two and 48 hours on chromogenic media to establish the time points of first growth, single colony appearance, and typical morphology for 10², 104, 106, and 108 colony forming units/mL. Subsequently, we imaged plates inoculated with 778 patient samples after 20, 24, and 36 hours. RESULTS: The first growth, single colony appearance, and typical morphology time points were inoculum-dependent. First growth appeared after 6-18 hours, 4-18 hours, and 8-48 hours for MRSA, MDRGN, and VRE, respectively, and single colonies appeared at 12-18 hours, 6-20 hours, and 12-48 hours, respectively. Typical morphology was visible at 14-22 hours and 12-48 hours for MRSA and VRE, but was not determined for MDRGN. By examining patient samples, ≥98% of MRSA and MDRGN were visible 20 hours after the start of incubation. Following 24 hours of incubation, only 79.5% of VRE were clearly visible on the respective plates. CONCLUSIONS: An incubation time of 20 hours is sufficient for detecting MRSA and MDRGN. VRE growth is much slower and requires additional imaging after 36 hours.
Assuntos
Bactérias Gram-Negativas/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Automação Laboratorial , Farmacorresistência Bacteriana Múltipla , Bactérias Gram-Negativas/isolamento & purificação , Humanos , Cinética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Reto/microbiologia , Fatores de Tempo , Enterococos Resistentes à Vancomicina/isolamento & purificaçãoRESUMO
Flavophospholipol (FPL) is an antimicrobial feed additive that has been approved for use in livestock animals and has the potential to decrease horizontal dissemination of antimicrobial resistance genes. Since previous studies showed that FPL has an inhibitory effect on plasmid transfer, in vitro experiments have proven the efficacy of FPL in reducing the conjugative transfer of plasmids encoding the extended-spectrum ß-lactamase (ESBL) and vanA genes. These are among the most important antimicrobial resistance loci known. ESBL-producing Escherichia coli and vancomycin-resistant Enterococcus faecalis (VRE) were exposed to several concentrations of FPL, and transfer frequency and plasmid curing activity were determined. FPL inhibited the conjugative transfer of plasmids harboring ESBL and vanA genes in a concentration-dependent manner in all strains. Further transfer experiments revealed that FPL could decrease or increase transfer frequency depending on plasmid type when transfer frequency was at low levels. The plasmid curing activity of FPL was also observed in ESBL-producing E. coli in a concentration-dependent manner, suggesting that they partially contribute to the inhibition of conjugative transfer. These results suggest that the use of FPL as a feed additive might decrease the dissemination of ESBL and vanA genes among livestock animals.
Assuntos
Antibacterianos/farmacologia , Bambermicinas/farmacologia , Conjugação Genética/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Escherichia coli/crescimento & desenvolvimento , Aditivos Alimentares/farmacologia , Transferência Genética Horizontal/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Ração Animal , Proteínas de Bactérias/genética , Carbono-Oxigênio Ligases/genética , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Escherichia coli/prevenção & controle , Infecções por Bactérias Gram-Positivas/prevenção & controle , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Plasmídeos/fisiologia , beta-Lactamases/genéticaRESUMO
Vancomycin-resistant enterococci (VRE) are an important cause of nosocomial infections in acute-care hospitals (ACHs), intermediate-care facilities (ITCFs), and long-term care facilities (LTCFs). This study contemporaneously compared the epidemiology and risk factors for VRE colonization in different care settings in a health care network. We conducted a serial cross-sectional study in a 1,700-bed ACH and its six closely affiliated ITCFs and LTCFs in June and July of 2014 to 2016. Rectal swab or stool specimens were cultured for VRE. Multivariable logistic regression was used to assess for independent risk factors associated with VRE colonization. Of 5,357 participants, 523 (9.8%) were VRE colonized. VRE prevalence was higher in ACHs (14.2%) than in ITCFs (7.6%) and LTCFs (0.8%). Common risk factors between ACHs and ITCFs included prior VRE carriage, a longer duration of antibiotic therapy, surgery in the preceding 90 days, and the presence of a skin ulcer. Independent risk factors specific to ACH-admitted patients were prior methicillin-resistant Staphylococcus aureus carriage, a higher number of beds per room, prior proton pump inhibitor use, and a length of stay of >14 days. For ITCFs, a length of stay of >14 days was inversely associated with VRE colonization. Similarities and differences in risk factors for VRE colonization were observed between health care settings. VRE prevention efforts should target the respective high-risk patients.
Assuntos
Infecção Hospitalar/epidemiologia , Infecções por Bactérias Gram-Positivas/epidemiologia , Hospitais , Resistência a Vancomicina , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Cuidados Críticos/estatística & dados numéricos , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Estudos Transversais , Feminino , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Tempo de Internação/estatística & dados numéricos , Assistência de Longa Duração/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Fatores de Risco , Singapura/epidemiologia , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimentoRESUMO
Background: In France, Carbapenem-Resistant Enterobacteriaceae (CRE) and Vancomycin-Resistant Enterococci (VRE) are considered as Extensively Drug-Resistant (XDR) bacteria. Their management requires reinforcement of hospital's hygiene policies, and currently there is few consistent data concerning the spontaneous decolonization in XDR colonized patients. Our aim is to study the natural history of decolonization of XDR carriers over time in a hospital setting in a low prevalence country. Material and methods: Retrospective multicenter study over 2 years (2015-2016) in 2 different tertiary care hospital sites and units having an agreement for permanent cohorting of such XDR carriers. We gathered the type of microorganisms, risk factors for colonization and rectal swabs from patient's follow-up. We also evaluated patient care considering isolation precautions. Results: We included 125 patients, aged 63+/-19y, including 72.8% of CRE (n = 91), 24.8% of VRE (n = 31) and 2.4% (n = 3) co-colonized with CRE and VRE. CRE were mainly E. coli (n = 54), K. pneumoniae (n = 51) and E. cloacae (n = 6). Mechanisms of resistance were mainly OXA-48 (n = 69), NDM-1 (n = 11), OXA-232 (n = 8) and KPC (n = 3).Prior antibiotic therapy was reported in 38.4% (n = 48) of cases. Conversely, 17.6% (n = 22) received antibiotics during follow-up.Spontaneous decolonization occurred within the first 30 days in 16.4% (n = 19/116) of cases and up to 48.2% after day-90 with a median follow-up of 96 days (0-974).We estimated that XDR carriage was associated with a larger care burden in 13.6% (n = 17) of cases, especially due to a prolongation of hospitalization of 32.5 days (15-300). Conclusions: Our study shows that spontaneous decolonization is increasing over time (up to 48.2%). We can regret that only few patients underwent screening after 1 year, emphasizing the need for more monitoring and prospective studies.
Assuntos
Antibacterianos/uso terapêutico , Enterobacteriáceas Resistentes a Carbapenêmicos/crescimento & desenvolvimento , Infecções por Enterobacteriaceae/tratamento farmacológico , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Adulto , Idoso , Idoso de 80 Anos ou mais , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Portador Sadio/tratamento farmacológico , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Farmacorresistência Bacteriana , Infecções por Enterobacteriaceae/epidemiologia , Infecções por Enterobacteriaceae/microbiologia , Feminino , França/epidemiologia , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Centros de Atenção Terciária/estatística & dados numéricos , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/genética , Enterococos Resistentes à Vancomicina/isolamento & purificação , Adulto JovemRESUMO
Commensal gastrointestinal bacteria resist the expansion of pathogens and are lost during critical illness, facilitating pathogen colonization and infection. We performed a prospective, ICU-based study to determine risk factors for loss of gut colonization resistance during the initial period of critical illness. Rectal swabs were taken from adult ICU patients within 4 hours of admission and 72 hours later, and analyzed using 16S rRNA gene sequencing and selective culture for vancomycin-resistant Enterococcus (VRE). Microbiome data was visualized using principal coordinate analyses (PCoA) and assessed using a linear discriminant analysis algorithm and logistic regression modeling. 93 ICU patients were analyzed. At 72 hours following ICU admission, there was a significant decrease in the proportion of Clostridial Clusters IV/XIVa, taxa that produce short chain fatty acids (SCFAs). At the same time, there was a significant expansion in Enterococcus. Decreases in Cluster IV/XIVa Clostridia were associated with loss of gut microbiome colonization resistance (reduced diversity and community stability over time). In multivariable analysis, both decreased Cluster IV/XIVa Clostridia and increased Enterococcus after 72 hours were associated with receipt of antibiotics. Cluster IV/XIVa Clostridia, although a small fraction of the overall gastrointestinal microbiome, drove distinct clustering on PCoA. During initial treatment for critical illness, there was a loss of Cluster IV/XIVa Clostridia within the distal gut microbiome which associated with an expansion of VRE and with a loss of gut microbiome colonization resistance. Receipt of broad-spectrum antibiotics was associated with these changes.
Assuntos
Clostridium/crescimento & desenvolvimento , Trato Gastrointestinal/microbiologia , Idoso , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Clostridium/efeitos dos fármacos , Clostridium/genética , Estado Terminal , Fezes/microbiologia , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Análise de Componente Principal , Estudos Prospectivos , RNA Ribossômico 16S/química , RNA Ribossômico 16S/metabolismo , Fatores de Tempo , Enterococos Resistentes à Vancomicina/genética , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/isolamento & purificaçãoRESUMO
Vancomycin-resistance among Enterococci has been escalating in recent years in many countries. Linezolid, an oxazolidinone is one of the novel drug that promised effective therapy of infections caused by vancomycin-resistant Enterococci (VRE).However, like with most of the previous antimicrobial agents, the clinical benefit of linezolid is being threatened by the emergence of resistant strains of MRSA and vancomycin resistant enterococci VRE, being reported in many countries. This study was conducted to establish linezolid susceptibility of VRE isolates by determining the in vitro activity of linezolid against vancomycin resistant Enterococci, isolated in our setup using fifty VRE isolates. The data collected from this study conclude that the vancomycin resistant Enterococci are 100% linezolid susceptible and presently there is no significant resistance against this unique oxazolidinone in our setup.
Assuntos
Antibacterianos/farmacologia , Linezolida/farmacologia , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/isolamento & purificação , Estudos Transversais , Humanos , Testes de Sensibilidade Microbiana/métodos , Resultado do Tratamento , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimentoRESUMO
Biofilms and the rapid evolution of multidrug resistance complicate the treatment of bacterial infections. Antibiofilm agents such as metallic-inorganic nanoparticles or peptides act by exerting antibacterial effects and, hence, do not combat biofilms of antibiotics-resistant strains. In this Letter, we show that the block copolymer DA95B5, dextran- block-poly((3-acrylamidopropyl) trimethylammonium chloride (AMPTMA)- co-butyl methacrylate (BMA)), effectively removes preformed biofilms of various clinically relevant multidrug-resistant Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE V583), and Enteroccocus faecalis (OG1RF). DA95B5 self-assembles into core-shell nanoparticles with a nonfouling dextran shell and a cationic core. These nanoparticles diffuse into biofilms and attach to bacteria but do not kill them; instead, they promote the gradual dispersal of biofilm bacteria, probably because the solubility of the bacteria-nanoparticle complex is enhanced by the nanoparticle dextran shell. DA95B5, when applied as a solution to a hydrogel pad dressing, shows excellent in vivo MRSA biofilm removal efficacy of 3.6 log reduction in a murine excisional wound model, which is significantly superior to that for vancomycin. Furthermore, DA95B5 has very low in vitro hemolysis and negligible in vivo acute toxicity. This new strategy for biofilm removal (nanoscale bacterial debridement) is orthogonal to conventional rapidly developing resistance traits in bacteria so that it is as effective toward resistant strains as it is toward sensitive strains and may have widespread applications.
Assuntos
Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Nanopartículas/administração & dosagem , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Antibacterianos/efeitos adversos , Dextranos/administração & dosagem , Dextranos/química , Humanos , Metacrilatos/administração & dosagem , Metacrilatos/química , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Nanopartículas/química , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/patogenicidadeRESUMO
The activities of four oxadiazoles were investigated with 210 methicillin-resistant Staphylococcus aureus (MRSA) strains. MIC50 and MIC90 values of 1 to 2 and 4 µg/ml, respectively, were observed. We also evaluated the activity of oxadiazole ND-421 against other staphylococci and enterococci and in the presence of oxacillin for selected MRSA strains. The MIC for ND-421 is lowered severalfold in combination with oxacillin, as they synergize. The MIC90 of ND-421 against vancomycin-resistant enterococci is ≤1 µg/ml.
Assuntos
Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Oxidiazóis/farmacologia , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Antibacterianos/química , Cefalosporinas/farmacologia , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Oxacilina/farmacologia , Oxidiazóis/química , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/crescimento & desenvolvimento , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/crescimento & desenvolvimento , Staphylococcus saprophyticus/efeitos dos fármacos , Staphylococcus saprophyticus/crescimento & desenvolvimento , Relação Estrutura-Atividade , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , CeftarolinaRESUMO
The spread of antibiotic resistance is one of the leading public health problems in Italy. A European Centre for Disease Prevention and Control country visit recently confirmed the major challenges and made important suggestions. In response, the Ministry of Health published the National Plan for Antimicrobial Resistance Containment, and a group of experts belonging to the Italian Group of Antimicrobial Stewardship (GISA) convened to develop a summary of practical recommendations. The GISA document is intended for use by practising physicians; it aims to increase the rational use of antimicrobials in the treatment of infections, and to change the culture of infection control of antibiotic-resistant bacteria, through the translation of theoretical knowledge into priority actions. This document has been endorsed by several national scientific societies, and reflects the particular challenges that are faced in Italy. Nevertheless, it is considered that the general principles and approaches discussed are relevant, particularly to other developed economies.
Assuntos
Antibacterianos/uso terapêutico , Gestão de Antimicrobianos/organização & administração , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/prevenção & controle , Saúde Pública/normas , Acinetobacter/efeitos dos fármacos , Acinetobacter/crescimento & desenvolvimento , Infecções Bacterianas/microbiologia , Vacinas Bacterianas/administração & dosagem , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Humanos , Itália , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimentoRESUMO
Antibiotics with novel bactericidal mechanisms of action are urgently needed. The antibiotic acyldepsipeptide 4 (ADEP4) activates the ClpP protease and causes cells to self-digest. The effects of ADEP4 and ClpP activation have not been characterized sufficiently for the enterococci, which are important pathogens known for high levels of acquired and intrinsic antibiotic resistance. In the present study, ADEP4 was found to be potently active against both Enterococcus faecalis and Enterococcus faecium, with MIC90s of 0.016 µg/ml and 0.031 µg/ml, respectively. ClpP purified from E. faecium was found to bind ADEP4 in a surface plasmon resonance analysis, and ClpP activation by ADEP4 was demonstrated biochemically with a ß-casein digestion assay. In addition, E. faecium ClpP was crystallized in the presence of ADEP4, revealing ADEP4 binding to ClpP in the activated state. These results confirm that the anti-enterococcal activity of ADEP4 occurs through ClpP activation. In killing curve assays, ADEP4 was found to be bactericidal against stationary-phase vancomycin-resistant E. faecalis (VRE) strain V583, and resistance development was prevented when ADEP4 was combined with multiple classes of approved antibiotics. ADEP4 in combination with partnering antibiotics also eradicated mature VRE biofilms within 72 h of treatment. Biofilm killing with ADEP4 antibiotic combinations was superior to that with the clinically used combinations ampicillin-gentamicin and ampicillin-daptomycin. In a murine peritoneal septicemia model, ADEP4 alone was as effective as ampicillin. ADEP4 coadministered with ampicillin was significantly more effective than either drug alone. These data suggest that ClpP-activating antibiotics may be useful for treating enterococcal infections.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/química , Depsipeptídeos/farmacologia , Endopeptidase Clp/química , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecium/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Ampicilina/farmacologia , Animais , Antibacterianos/química , Proteínas de Bactérias/agonistas , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Cristalografia por Raios X , Depsipeptídeos/química , Modelos Animais de Doenças , Combinação de Medicamentos , Endopeptidase Clp/genética , Endopeptidase Clp/metabolismo , Enterococcus faecalis/enzimologia , Enterococcus faecalis/genética , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecium/enzimologia , Enterococcus faecium/genética , Enterococcus faecium/crescimento & desenvolvimento , Ativação Enzimática/efeitos dos fármacos , Feminino , Expressão Gênica , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Camundongos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Sepse/tratamento farmacológico , Sepse/microbiologia , Vancomicina/farmacologia , Enterococos Resistentes à Vancomicina/enzimologia , Enterococos Resistentes à Vancomicina/genética , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimentoRESUMO
Enterococci are commensal micro-organisms present in the gastrointestinal tract of humans. Although normally innocuous to the host, strains of enterococcus exhibiting resistance to vancomycin (VRE) have been associated with high rates of infection and mortality in immunocompromised patients. Decolonization of VRE represents a key strategy to curb infection in highly-susceptible patients. However, there is a dearth of decolonizing agents available clinically that are effective against VRE. The present study found that niclosamide, an anthelmintic drug, has potent antibacterial activity against clinical isolates of vancomycin-resistant Enterococcus faecium (minimum inhibitory concentration 1-8 µg/mL). E. faecium mutants exhibiting resistance to niclosamide could not be isolated even after multiple (10) serial passages. Based upon these promising in-vitro results and the limited permeability of niclosamide across the gastrointestinal tract (when administered orally), niclosamide was evaluated in a VRE colonization-reduction murine model. Remarkably, niclosamide outperformed linezolid, an antibiotic used clinically to treat VRE infections. Niclosamide was as effective as ramoplanin in reducing the burden of vancomycin-resistant E. faecium in the faeces, caecal content and ileal content of infected mice after only 8 days of treatment. Linezolid, in contrast, was unable to decrease the burden of VRE in the gastrointestinal tract of mice. The results obtained indicate that niclosamide warrants further evaluation as a novel decolonizing agent to suppress VRE infections.
Assuntos
Antibacterianos/uso terapêutico , Reposicionamento de Medicamentos , Intestinos/microbiologia , Niclosamida/uso terapêutico , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Animais , Depsipeptídeos/uso terapêutico , Fezes/microbiologia , Humanos , Linezolida/uso terapêutico , Camundongos , Testes de Sensibilidade Microbiana , Oxiclozanida/farmacologia , Rafoxanida/farmacologia , Salicilanilidas/farmacologia , Vancomicina/farmacologia , Resistência a Vancomicina , Enterococos Resistentes à Vancomicina/efeitos dos fármacosRESUMO
Modern medicine is challenged continuously by the increasing prevalence of antibiotic resistant bacteria. Cationic antimicrobial peptides and their derivatives are interesting potential alternatives to antibiotics due to their rapid action, broad-spectrum of antimicrobial activity and limited emergence of bacterial resistance. This study reports the novel antimicrobial properties of histone H5, purified from chicken erythrocytes, and histone H5-derived synthetic peptides. Broth microdilution assays revealed that histone H5 has potent broad-spectrum antimicrobial activity against Gram-positive and Gram-negative planktonic bacteria (MIC range: 1.9 ± 1.8 to 4.9 ± 1.5 µg/mL), including vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA). Moreover, histone H5 displayed anti-biofilm activity against established Listeria monocytogenes and Pseudomonas aeruginosa biofilms. Scanning electron microscopy demonstrated bacterial membrane damage after histone H5 treatment, while a hemolytic assay revealed that histone H5 is non-toxic towards mammalian erythrocytes, even at a concentration of 1 mg/mL. Although the predicted H5-derived antimicrobial peptides tested in this study were located within the antimicrobial domain of histone H5, their synthetic versions did not possess more potent antimicrobial activity than the full length protein. Overall, this study demonstrates that histone H5 is a potent antimicrobial and therefore a promising template for the development of novel histone H5-derived antimicrobial peptides.
Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes/efeitos dos fármacos , Histonas/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Peptídeos/farmacologia , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antibacterianos/síntese química , Peptídeos Catiônicos Antimicrobianos/síntese química , Biofilmes/crescimento & desenvolvimento , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , Galinhas , Relação Dose-Resposta a Droga , Eritrócitos/química , Hemólise/efeitos dos fármacos , Histonas/química , Histonas/isolamento & purificação , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/ultraestrutura , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/ultraestrutura , Testes de Sensibilidade Microbiana , Peptídeos/síntese química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/ultraestrutura , Alinhamento de Sequência , Relação Estrutura-Atividade , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/ultraestruturaRESUMO
Iclaprim is a bacterial dihydrofolate reductase inhibitor that is currently being evaluated in two phase 3 trials for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSI). Prior animal infection model studies suggest that the pharmacokinetic/pharmacodynamic (PK/PD) drivers for efficacy are area under the concentration-time curve from 0 to 24 h at steady state (AUC0-24ss), AUC/MIC, and time above the MIC during the dosing interval (T > MIC), while QTc prolongation was associated with the maximal concentration at steady state (Cmaxss) in a thorough QTc phase 1 study. Using PK data collected from 470 patients from the previously conducted phase 3 complicated skin and skin structure infection (cSSSI) trials, population PK modeling and Monte Carlo simulation (MCS) were used to identify a fixed iclaprim dosage regimen for the ongoing phase 3 ABSSSI studies that maximizes AUC0-24ss, AUC/MIC, and T > MIC while minimizing the probability of a Cmaxss of ≥800 ng/ml relative to the values for the previously employed cSSSI regimen of 0.8 mg/kg of body weight infused intravenously over 0.5 h every 12 h. The MCS analyses indicated that administration of 80 mg as a 2-h infusion every 12 h provides 28%, 28%, and 32% increases in AUC0-24ss, AUC/MIC, and T > MIC, respectively, compared to values for the 0.8-mg/kg cSSSI regimen, while decreasing the probability of a Cmaxss of ≥800 ng/ml, by 9%. Based on PK/PD analyses, 80 mg iclaprim administered over 2 h every 12 h was selected as the dosing scheme for subsequent phase 3 clinical trials.
Assuntos
Antibacterianos/farmacocinética , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Modelos Estatísticos , Infecções Pneumocócicas/tratamento farmacológico , Pirimidinas/farmacocinética , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Adulto , Idoso , Antibacterianos/sangue , Antibacterianos/farmacologia , Área Sob a Curva , Método Duplo-Cego , Esquema de Medicação , Cálculos da Dosagem de Medicamento , Feminino , Infecções por Bactérias Gram-Positivas/sangue , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/patologia , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Método de Monte Carlo , Infecções Pneumocócicas/sangue , Infecções Pneumocócicas/microbiologia , Infecções Pneumocócicas/patologia , Pirimidinas/sangue , Pirimidinas/farmacologia , Infecções Cutâneas Estafilocócicas/sangue , Infecções Cutâneas Estafilocócicas/microbiologia , Infecções Cutâneas Estafilocócicas/patologia , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimentoRESUMO
ABSTRACT Rapid identification of vancomycin-resistant enterococci (VRE) can assist in choosing the appropriate treatment and preventing VRE spread. The performance of chromIDTM VRE agar was evaluated using 184 clinical isolates of Enterococcus spp. and reference strains. The test had a sensitivity of 95.52% but a low specificity of 30%.