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1.
PLoS One ; 15(2): e0228781, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32059020

RESUMO

BACKGROUND: Over the last three decades, hospital adapted clonal complex (CC) 17 strains of Enterococcus faecium have acquired and exchanged antimicrobial resistance genes leading to the widespread resistance to clinically important antimicrobials globally. In Australia, a high prevalence of vancomycin resistance has been reported in E. faecium in the last decade. METHODS: In this study, we determined the phylogenetic relationship and genetic characteristics of E. faecium collected from hospitalized patients with blood stream infections throughout Australia from 2015 to 2017 using high throughput molecular techniques. RESULTS: Using single nucleotide polymorphism based phylogenetic inference, three distinct clusters of isolates were observed with additional sub-clustering. One cluster harboured mostly non-CC17 isolates while two clusters were dominant for the vanA and vanB operons. CONCLUSION: The gradual increase in dominance of the respective van operon was observed in both the vanA and vanB dominant clusters suggesting a strain-van operon affinity. The high prevalence of the van operon within isolates of a particular sub-cluster was linked to an increased number of isolates and 30-day all-cause mortality. Different dominant sub-clusters were observed in each region of Australia. Findings from this study can be used to put future surveillance data into a broader perspective including the detection of novel E. faecium strains in Australia as well as the dissemination and evolution of each strain.


Assuntos
Enterococcus faecium/genética , Enterococcus faecium/fisiologia , Sepse/microbiologia , Sequenciamento Completo do Genoma , Austrália , Enterococcus faecium/efeitos dos fármacos , Humanos , Filogenia , Polimorfismo de Nucleotídeo Único , Resistência a Vancomicina/genética
2.
Arch Oral Biol ; 110: 104617, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31794906

RESUMO

Streptococcus mutans and Candida albicans are the main oral pathogens which contribute to dental caries that affects all ages of human being. OBJECTIVES: This study focuses on the potential of crude cell free supernatant (CCFS) from lactic acid bacteria (LAB) to inhibit of the growth of S. mutans UKMCC 1019. DESIGN: A total of 61 CCFS from LAB strains were screened for their inhibitory ability against S. mutans UKMCC 1019 by broth microdilution method. The selected LAB with highest antimicrobial activity was identified and its CCFS was characterized for pH stability, temperature tolerance, enzyme sensitivity, metabolism of carbohydrates, enzymatic activities and antimicrobial activity against S. mutans UKMCC 1019 and C. albicans UKMCC 3001 by well diffusion assay. The effect of CCFS on cell structure of S. mutans UKMCC 1019 was observed under transmission electron microscopy (TEM). RESULTS: The CCFS from isolate CC2 from Kimchi showed the highest inhibition against S. mutans UKMCC 1019, which was 76.46 % or 4406.08 mm2/mL and it was identified to be most closely related to Enterococcus faecium DSM 20477 based on 16 s rRNA sequencing. The CCFS of E. faecium DSM 20477 had high tolerance to acidic and alkaline environment as well as high temperature. It also shows high antifungal activities against C. albicans UKMCC 3001 with 2362.56 mm2/mL. Under TEM, the cell walls and the cytoplasm membrane of S. mutans UKMCC 1019 were disrupted by the antimicrobial substance, causing cell lysis. CONCLUSIONS: Hence, the CCFS from E. faecium DSM 20477 is a potential bacteriocin in future for the treatment of dental caries.


Assuntos
Anti-Infecciosos , Cárie Dentária , Enterococcus faecium , Streptococcus mutans , Antibacterianos , Anti-Infecciosos/farmacologia , Biofilmes , Cárie Dentária/microbiologia , Enterococcus faecium/isolamento & purificação , Enterococcus faecium/fisiologia , Humanos , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/patogenicidade
3.
J Dairy Sci ; 103(1): 379-395, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31629529

RESUMO

Dairy farmers are often challenged with the need to feed high-moisture corn (HMC) after less than 30 d of fermentation. The objective this study was to assess the effects of microbial inoculation and particle size on fermentation profile, aerobic stability, and ruminal in situ starch degradation of HMC ensiled for a short period. High-moisture corn was harvested, coarsely ground (3,798 ± 40 µm, on average) or finely ground (984 ± 42 µm, on average), then ensiled in quadruplicate vacuum pouches untreated (CON) or with the following treatments: Lactobacillus plantarum CH6072 at 5 × 104 cfu/g and Enterococcus faecium CH212 at 5 × 104 cfu/g of fresh forage (LPEF); or Lactobacillus buchneri LB1819 at 7.5 × 104 cfu/g and Lactococcus lactis O224 at 7.5 × 104 cfu/g (LBLL). Silos were allowed to ferment for 14 or 28 d. Ruminal in situ starch degradation increased when HMC was finely ground. In addition, in situ starch degradation was greater and aerobic stability increased approximately 5-fold with LBLL compared with CON and LPEF. An interaction between microbial inoculation and storage length occurred for lactic acid. At 14 d, concentrations of lactic acid were greatest in LPEF and lowest in LBLL. Lactic acid concentrations increased from 14 to 28 d with CON and LPEF, but decreased with LBLL. At 28 d, concentrations of lactic acid were lower in LBLL compared with CON and LPEF. An interaction between particle size, microbial inoculation, and storage length occurred for acetic acid and ammonia-N. At 14 and 28 d, acetic acid concentrations were greatest in finely ground LBLL followed by coarsely ground LBLL. Ammonia-N concentrations increased across all treatments from 0 to 28 d. At 14 and 28 d, concentrations of ammonia-N were greatest in finely ground LBLL and lowest in coarsely ground CON and coarsely ground LPEF. Results from this study suggest that L. buchneri LB1819 can produce acetic acid in as little as 14 d, and that by 28 d, it has the potential to improve the aerobic stability of HMC. Additionally, results indicate that L. buchneri LB1819 has the potential to improve ruminal degradation of starch by 28 d of storage. Finally, results confirm enhanced fermentation and improved ruminal starch degradation with finely ground HMC by 28 d of storage.


Assuntos
Enterococcus faecium/fisiologia , Lactobacillus/fisiologia , Silagem/análise , Amido/metabolismo , Zea mays , Ácido Acético/metabolismo , Aerobiose , Inoculantes Agrícolas , Animais , Fermentação , Lactobacillus/classificação , Tamanho da Partícula , Silagem/microbiologia , Amido/química , Zea mays/metabolismo , Zea mays/microbiologia
4.
Nat Commun ; 10(1): 4569, 2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31594927

RESUMO

Bacterial pathogens that infect patients also contaminate hospital surfaces. These contaminants impact hospital infection control and epidemiology, prompting quantitative examination of their transmission dynamics. Here we investigate spatiotemporal and phylogenetic relationships of multidrug resistant (MDR) bacteria on intensive care unit surfaces from two hospitals in the United States (US) and Pakistan collected over one year. MDR bacteria isolated from 3.3% and 86.7% of US and Pakistani surfaces, respectively, include common nosocomial pathogens, rare opportunistic pathogens, and novel taxa. Common nosocomial isolates are dominated by single lineages of different clones, are phenotypically MDR, and have high resistance gene burdens. Many resistance genes (e.g., blaNDM, blaOXA carbapenamases), are shared by multiple species and flanked by mobilization elements. We identify Acinetobacter baumannii and Enterococcus faecium co-association on multiple surfaces, and demonstrate these species establish synergistic biofilms in vitro. Our results highlight substantial MDR pathogen burdens in hospital built-environments, provide evidence for spatiotemporal-dependent transmission, and demonstrate potential mechanisms for multi-species surface persistence.


Assuntos
Antibacterianos/farmacologia , Infecção Hospitalar/transmissão , Farmacorresistência Bacteriana Múltipla/genética , Contaminação de Equipamentos , Unidades de Terapia Intensiva , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/fisiologia , Antibacterianos/uso terapêutico , Biofilmes/efeitos dos fármacos , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/isolamento & purificação , Enterococcus faecium/fisiologia , Humanos , Testes de Sensibilidade Microbiana , Paquistão , Análise Espaço-Temporal , Estados Unidos
5.
Artigo em Inglês | MEDLINE | ID: mdl-31533204

RESUMO

Enterococci are commonly found in humans, animals and environments. Their highly adaptive mechanisms are related to several virulent determinants and their ability to resist antibiotics. Data on the relationship between the esp gene, biofilm formation and antibiotic susceptibility profiles may differ between countries. This cross-sectional study was conducted to determine the proportion of esp gene and biofilm formation among Enterococcus faecalis and Enterococcus faecium clinical isolates. We also investigated the possible association between the esp gene with antibiotic susceptibility patterns and biofilm formation. The isolates were collected from clinical samples and identified using biochemical tests and 16SRNA. Antibiotic susceptibility patterns and a biofilm assay were conducted according to the established guidelines. Molecular detection by PCR was used to identify the esp gene using established primers. In total, 52 and 28 of E. faecalis and E. faecium were identified, respectively. E. faecium exhibited higher resistance rates compared to E. faecalis as follows: piperacillin/tazobactam (100% versus 1.9%), ampicillin (92.8% versus 1.9%), high-level gentamicin resistance (HLGR) (89.3% versus 25.0%) and penicillin (82.1% versus 7.7%). E. faecium produced more biofilms than E. faecalis (59.3% versus 49.0%). E. faecium acquired the esp gene more frequently than E. faecalis (78.6% versus 46.2%). Interestingly, the associations between ampicillin and tazobactam/piperacillin resistance with the esp gene were statistically significant (X2 = 4.581, p = 0.027; and X2 = 6.276, p = 0.012, respectively). Our results demonstrate that E. faecium exhibits high rates of antimicrobial resistance, esp gene acquisition and biofilm formation. These peculiar traits of E. faecium may have implications for the management of enterococcal infections in hospitals. Thus, concerted efforts by all parties in establishing appropriate treatment and effective control measures are warranted in future.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Biofilmes , Enterococcus faecalis/fisiologia , Enterococcus faecium/fisiologia , Proteínas de Membrana/genética , Proteínas de Bactérias/metabolismo , Estudos Transversais , Enterococcus faecalis/genética , Enterococcus faecium/genética , Malásia , Proteínas de Membrana/metabolismo , Testes de Sensibilidade Microbiana
6.
J Microbiol Biotechnol ; 29(10): 1591-1602, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31546297

RESUMO

To shed light on the genetic basis of salt tolerance in Enterococcus faecium, Enterococcus faecalis, and Tetragenococcus halophilus, we performed comparative genome analysis of 10 E. faecalis, 11 E. faecium, and three T. halophilus strains. Factors involved in salt tolerance that could be used to distinguish the species were identified. Overall, T. halophilus contained a greater number of potassium transport and osmoprotectant synthesis genes compared with the other two species. In particular, our findings suggested that T. halophilus may be the only one among the three species capable of synthesizing glycine betaine from choline, cardiolipin from glycerol and proline from citrate. These molecules are well-known osmoprotectants; thus, we propose that these genes confer the salt-tolerance of T. halophilus.


Assuntos
Enterococcus faecalis/fisiologia , Genoma Bacteriano/genética , Tolerância ao Sal/genética , Proteínas de Bactérias/genética , Enterococcaceae/genética , Enterococcaceae/fisiologia , Enterococcus faecalis/genética , Enterococcus faecium/genética , Enterococcus faecium/fisiologia , Proteínas de Membrana Transportadoras , Especificidade da Espécie
7.
Microbiol Res ; 228: 126305, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31422234

RESUMO

Traditional culture-based enumeration methods were compared with the ethidium monoazide quantitative polymerase chain reaction (EMA-qPCR) technique to assess Bdellovibrio-and-like-organisms (BALOs) predator-prey interactions. Gram-negative [Pseudomonas spp. and Klebsiella pneumoniae (K. pneumoniae)] and Gram-positive [Staphylococcus aureus (S. aureus) and Enterococcus faecium (E. faecium)] organisms were employed as prey cells, while a Bdellovibrio bacteriovorus strain (PF13) was used as the predator. The co-culture experiments were also compared in diluted nutrient broth (DNB) and HEPES buffer. In both media, K. pneumoniae (maximum log reduction of 5.13) and Pseudomonas fluorescens (P. fluorescens) (maximum log reduction of 4.21) were sensitive to predation by B. bacteriovorus PF13 as their cell counts and gene copies were reduced during all the co-culture experiments, while the concentration of B. bacteriovorus PF13 increased. The concentration of B. bacteriovorus PF13 also increased in the presence of S. aureus (HEPES buffer) and E. faecium (DNB), indicating that the predator interacted with these Gram-positive prey in order to survive. Moreover, as no predator plaques were produced in the co-culture experiments with P. aeruginosa (DNB and HEPES buffer), S. aureus (DNB and HEPES buffer) and E. faecium (HEPES buffer), EMA-qPCR proved to be beneficial in monitoring the concentration of B. bacteriovorus. In conclusion, the cell counts and/or EMA-qPCR analysis for the HEPES buffer and DNB assays were successfully employed to monitor the predation of P. fluorescens and K. pneumoniae by B. bacteriovorus, while E. faecium was sensitive to predation in DNB and S. aureus was sensitive to predation in HEPES buffer.


Assuntos
Azidas , Fenômenos Fisiológicos Bacterianos , Interações Microbianas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Bactérias , Bdellovibrio bacteriovorus/fisiologia , Técnicas de Cocultura , Contagem de Colônia Microbiana , Enterococcus faecium/fisiologia , Klebsiella pneumoniae/fisiologia , Pseudomonas/fisiologia , Staphylococcus aureus/fisiologia , Águas Residuárias/microbiologia , Purificação da Água
8.
Res Vet Sci ; 125: 333-344, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31352282

RESUMO

Minthostachys verticillata essential oil (EO) is a natural product that reports immunomodulatory effects on human T cells as well as anti-inflammatory activity. Bovine mastitis is a worldwide disease, mainly caused by bacteria, affecting milk quality and yield, leading to high economic losses. Environmental pathogens, as Enterococcus faecium, are implicated in the disease. Antibiotic therapy is adequate, although it can leave residues in milk, causing problems in human health. The search of immunomodulatory substances for bovine mastitis treatment is a promising alternative strategy. The aim of this study was to characterize the effect of M. verticillata EO on macrophage phagocytosis and evaluate its immunomodulatory and protective effects in mice challenged with E. faecium. The results showed that EO activated macrophage phagocytosis mechanisms inducing reactive oxygen species production. Moreover, EO modulated the innate immune response in mammary glands of female Balb/c mice challenged with E. faecium decreasing the infiltration of polymorphonuclear neutrophils and IL-1ß and TNF-α mRNA expression. In addition, EO increased the expression of IL-10 in the last hours of infection. Treatment with EO did not increase the number of activated CD4+ or CD8+ T cells or the production of specific antibodies. These results suggest that EO play an important role in helping to resolve the infection in the first hours without activating adaptive immunity. In addition, a marked decrease of the bacterial count in the glands of mice treated with EO was observed. A natural product such as M. verticillata EO could have a potential use to control bovine mastitis.


Assuntos
Enterococcus faecium/fisiologia , Imunidade Inata/efeitos dos fármacos , Lamiaceae/química , Macrófagos/efeitos dos fármacos , Mastite Bovina/tratamento farmacológico , Óleos Voláteis/farmacologia , Fagocitose/efeitos dos fármacos , Animais , Bovinos , Feminino , Fatores Imunológicos/farmacologia , Macrófagos/imunologia , Mastite Bovina/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Óleos Voláteis/química , Substâncias Protetoras/farmacologia
9.
BMC Genomics ; 20(1): 602, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31331270

RESUMO

BACKGROUND: As an important nosocomial pathogen, Enterococcus faecium has received increasing attention in recent years. However, a large number of studies have focused on the hospital-associated isolates and ignored isolates originated from the natural environments. RESULTS: In this study, comparative genomic analysis was conducted on 161 isolates originated from human, animal, and naturally fermented dairy products. The results showed that the environment played an important role in shaping the genomes of Enterococcus faecium. The isolates from human had the largest average genome size, while the isolates from dairy products had the smallest average genome size and fewest antibiotic resistance genes. A phylogenetic tree was reconstructed based on the genomes of these isolates, which revealed new insights into the phylogenetic relationships among the dairy isolates and those from hospitals, communities, and animals. Furthermore, 202 environment-specific genes were identified, including 136 dairy-specific, 31 human blood-specific, and 35 human gastrointestinal-specific genes. Interestingly, five dairy-specific genes (namely lacF, lacA/B, lacD, lacG, and lacC) that constituted an integrated lactose metabolism pathway existed in almost all dairy isolates. The pathway conservation demonstrated an active role of the environment in shaping the genomes of Enterococcus faecium. CONCLUSIONS: This study shows that the Enterococcus faecium species has great genomic plasticity and high versatility to occupy broad ecological roles, dwelling as non-harmful dairy and animal gut commensals as well as significant nosocomial pathogens that disseminate antibiotic resistance genes.


Assuntos
Adaptação Fisiológica/genética , Enterococcus faecium/genética , Enterococcus faecium/fisiologia , Meio Ambiente , Genômica , Bases de Dados Genéticas , Resistência Microbiana a Medicamentos/genética , Enterococcus faecium/efeitos dos fármacos , Genes Bacterianos/genética , Filogenia , Fatores de Virulência/genética
10.
PLoS One ; 14(6): e0218679, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31251760

RESUMO

Streptococcus pneumonia is an important human pathogen that causes various severe diseases such as pneumonia, otitis and meningitis. Vaccination against S. pneumoniae is implemented in many developed countries. The presently used vaccines are safe, well tolerated but relatively expensive and require modification due to the immunological changes of the epidemic strains. This paper describes the development of a new pneumococcal vaccine candidate for immunization on mucosal surfaces. For this purpose the antigens of chimeric protein PSPF, previously suggested for an injectable S. pneumoniae vaccine, were expressed on the surface of the live probiotic strain Enterococcus faecium L3. Experiments on laboratory mice vaccinated with live bacteria demonstrated the appearance of the specific IgA and IgG which provide protection against the lethal S. pneumoniae infection.


Assuntos
Antígenos de Bactérias/metabolismo , Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas/administração & dosagem , Probióticos/administração & dosagem , Streptococcus pneumoniae/imunologia , Transativadores/metabolismo , Animais , Anticorpos Antibacterianos/metabolismo , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Enterococcus faecium/genética , Enterococcus faecium/fisiologia , Feminino , Imunoglobulina A/metabolismo , Imunoglobulina G/metabolismo , Camundongos , Infecções Pneumocócicas/imunologia , Vacinas Pneumocócicas/imunologia , Proteínas Recombinantes , Transativadores/genética
11.
Food Microbiol ; 82: 135-141, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027767

RESUMO

Salmonella is capable of surviving in a low moisture environment for long periods. Once adapted to the xeric conditions, the thermal resistance of Salmonella is enhanced. Cocoa powder is a low water activity (aw) food (LawF) that is an essential component in a wide variety of desserts and ready-to-eat (RTE) foods and drinks. The aim of this study was to evaluate the desiccation and thermal resistance of Salmonella in cocoa powder, as well as to examine the suitability of Enterococcus faecium NRRL B-2354 as a surrogate for Salmonella during cocoa powder thermal processing. Natural unsweetened cocoa powder was inoculated with a 3-strain Salmonella cocktail or E. faecium and was equilibrated to aw 0.30 and 0.45 at room temperature, then subjected to isothermal treatments at 70-80 °C or 12-month storage at RT (room temperature, 22.0 ±â€¯0.5 °C, aw 0.30). At 70 and 80 °C, D-values of both Salmonella and E. faecium increased with decreasing aw. D-values of Salmonella at aw 0.30 cocoa powder were 46.2 ±â€¯4.7, 20.5 ±â€¯1.7, and 11.5 ±â€¯0.9 min at 70, 75 and 80 °C, respectively. Higher heat resistance of E. faecium in aw 0.30 cocoa powder was observed with D-values of 59.9 ±â€¯5.0, 28.9 ±â€¯1.8, and 16.1 ±â€¯1.4 min at 70, 75, and 80 °C, respectively. However, E. faecium demonstrated less heat resistance than Salmonella when aw was increased to 0.45. D-values for Salmonella at aw 0.45 were 31.6-7.0 min at 70-80 °C compared to 25.8-4.7 min for E. faecium. During 12 months of storage at RT, surviving E. faecium population in aw 0.30 cocoa powder was higher than that of the Salmonella cocktail; the population decreased by 1.39 and 3.75 logs, respectively. These findings indicate that the suitability of E. faecium as a surrogate organism for Salmonella is influenced by aw of cocoa powder. The aw correlates with thermal inactivation rates in both Salmonella and E. faecium, and should be considered as a significant contributor to the thermal resistance of Salmonella in cocoa powder.


Assuntos
Chocolate/microbiologia , Enterococcus faecium/isolamento & purificação , Manipulação de Alimentos , Temperatura Alta , Viabilidade Microbiana , Salmonella/fisiologia , Contagem de Colônia Microbiana , Dessecação , Enterococcus faecium/fisiologia , Microbiologia de Alimentos , Armazenamento de Alimentos , Salmonella/isolamento & purificação , Fatores de Tempo , Água/análise
12.
Food Microbiol ; 82: 388-397, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027798

RESUMO

Salmonella persistence in ground black pepper has caused several foodborne outbreaks and created public concern about the safety of low water activity (aw) foods. In this study, radiofrequency (RF) processing was evaluated for pasteurization of ground black pepper. Stability and homogeneity tests were done for both Salmonella spp. and E. faecium during moisture equilibration before RF heating to evaluate the inoculation method. Moisture content of samples were conditioned such that the final moisture content after RF heating reached the optimal storage moisture. RF heating was shown to provide more than 5.98 log CFU/g reduction for Salmonella spp. and the reduction of 3.89 log CFU/g for E. faecium with a 130 s of treatment time. The higher thermal resistance of E. faecium indicated its suitability as surrogate for Salmonella spp. during RF heating of ground black pepper. Piperine, total phenolics, volatile compounds, and antioxidant activity were assessed as quality parameters for ground black pepper. The results demonstrated that the RF processing provided effective inactivation of Salmonella spp. with insignificant (p > 0.05) quality deterioration.


Assuntos
Enterococcus faecium/crescimento & desenvolvimento , Microbiologia de Alimentos , Calefação/métodos , Pasteurização/métodos , Piper nigrum/microbiologia , Salmonella/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Enterococcus faecium/fisiologia , Qualidade dos Alimentos , Temperatura Alta , Piper nigrum/química , Salmonella/fisiologia , Especiarias/microbiologia , Água/análise
13.
Infect Immun ; 87(6)2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30936157

RESUMO

Enterococcus faecalis is a human intestinal pathobiont with intrinsic and acquired resistance to many antibiotics, including vancomycin. Nature provides a diverse and virtually untapped repertoire of bacterial viruses, or bacteriophages (phages), that could be harnessed to combat multidrug-resistant enterococcal infections. Bacterial phage resistance represents a potential barrier to the implementation of phage therapy, emphasizing the importance of investigating the molecular mechanisms underlying the emergence of phage resistance. Using a cohort of 19 environmental lytic phages with tropism against E. faecalis, we found that these phages require the enterococcal polysaccharide antigen (Epa) for productive infection. Epa is a surface-exposed heteroglycan synthesized by enzymes encoded by both conserved and strain-specific genes. We discovered that exposure to phage selective pressure favors mutation in nonconserved epa genes both in culture and in a mouse model of intestinal colonization. Despite gaining phage resistance, epa mutant strains exhibited a loss of resistance to cell wall-targeting antibiotics. Finally, we show that an E. faecalis epa mutant strain is deficient in intestinal colonization, cannot expand its population upon antibiotic-driven intestinal dysbiosis, and fails to be efficiently transmitted to juvenile mice following birth. This study demonstrates that phage therapy could be used in combination with antibiotics to target enterococci within a dysbiotic microbiota. Enterococci that evade phage therapy by developing resistance may be less fit at colonizing the intestine and sensitized to vancomycin, preventing their overgrowth during antibiotic treatment.


Assuntos
Antibacterianos/farmacologia , Bacteriófagos/fisiologia , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/virologia , Enterococcus faecium/virologia , Infecções por Bactérias Gram-Positivas/terapia , Intestinos/microbiologia , Animais , Terapia Biológica , Enterococcus faecalis/imunologia , Enterococcus faecalis/fisiologia , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/imunologia , Enterococcus faecium/fisiologia , Feminino , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Vancomicina/farmacologia
14.
J Anim Physiol Anim Nutr (Berl) ; 103(3): 915-924, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30854744

RESUMO

Effects of probiotics on the intestinal microbiota of foals are yet insufficiently studied. The aim of this study was to investigate whether supplementation of Lactobacillus rhamnosus (DSM 7133) and Enterococcus faecium (DSM 7134) influences the bacterial composition of the faecal microbiota of foals. A total of 34 newborn foals were randomly assigned to the placebo group (PG, n = 16) and the treatment group (TG, n = 18). From day 1 to day 14 of life, foals orally received 3 ml of either a probiotic preparation (1.05 × 109 CFU E. faecium and 4.50 × 108 CFU L. rhamnosus) or placebo (carrier) once a day. Faeces were collected directly from the rectum immediately after birth (meconium) and at day 14 and day 56 of life. Samples of 12 foals per group were selected for microbiological analysis. DNA was extracted and used for polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative PCR. No DNA or amplicons were obtained from meconium. There were no differences in richness of bands and Shannon index of diversity regarding the Clostridium cluster XIVa between groups. Cluster analysis and principal coordinate analysis of DGGE data showed a clear effect of age. Band-based similarity of bacterial clusters (Dice coefficient) decreased from day 14 to day 56 of life (p < 0.001) in PG foals only resulting in lower similarity in PG versus TG foals when 2 month old (p < 0.01). Five of thirty re-amplified bands were identified on species level. Others were assigned either to family (mainly Lachnospiraceae) or genus level (Akkermansia). The bands related to Akkermansia muciniphila or Akkermansia spp. appeared almost in all DGGE profiles. Two-week supplementation of the probiotic preparation to foals had no significant impact on the composition of the faecal microbiota but it appears to have prevented the reduction of bacterial similarity between 2 and 8 weeks of age observed in not treated foals.


Assuntos
Suplementos Nutricionais , Enterococcus faecium/fisiologia , Fezes/microbiologia , Cavalos/microbiologia , Lactobacillus rhamnosus/fisiologia , Probióticos/administração & dosagem , Animais , Distribuição Aleatória
15.
J Hosp Infect ; 103(1): e88-e91, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30711531

RESUMO

The bactericidal activity of isopropanol was determined against Enterococcus faecium ATCC 6057, ST 796 (isopropanol-tolerant strain) and Enterococcus hirae ATCC 10541 (EN 13727). Isopropanol at 60% and 70% were effective (≥5.38 log10-reduction) in 15 s against all strains but 23% isopropanol was not (<0.99 log10-reduction in ≤15 min). Isopropanol at 70% was tested against E. faecium in the four-field test. Eight millilitres was not effective enough in 1 min (<5 log10-reduction), whilst 16 mL was effective (≥5.85 log10-reduction). Healthcare workers can be reassured that 60% and 70% isopropanol with an appropriate volume are effective against E. faecium.


Assuntos
2-Propanol/farmacologia , Desinfetantes/farmacologia , Tolerância a Medicamentos , Enterococcus faecium/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Enterococcus faecium/fisiologia , Streptococcus faecium ATCC 9790/efeitos dos fármacos , Streptococcus faecium ATCC 9790/fisiologia , Humanos
16.
Food Sci Technol Int ; 25(3): 233-242, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30518258

RESUMO

The main objectives of this work were to study the survivability of five probiotic lactobacilli strains in sour cherry juice and citrate buffer with similar pH values (pH 3.5) during storage at 4 ℃ as well as to encapsulate the strain with the least survival in calcium alginate beads. Enterococcus faecium from probiotic strains in sour cherry juice exhibited the least survival; therefore, this strain was selected for studying the protective effect of microencapsulation in calcium alginate beads. Microencapsulated probiotic cells were incorporated into sour cherry juice and then exposed to harsh conditions (e.g. heat treatment, low pH, and simulated gastrointestinal fluids). Changes in the probiotic survivability, pH and titratable acidity of sour cherry juice were monitored during 60 d. D-values of free cells, calculated at 60, 70 and 80 ℃, were 4.87, 1.48 and 0.43 min, respectively; while, those of microencapsulated cells were 9.41, 3.73 and 1.26 min, respectively. The decrease in the number of free E. faecium after exposure to low pH values (e.g. 2.5, 2 and 1.5) was 2.81, 3.74 and 4.18 log CFU/mL, respectively. Freshly prepared and 30-d old microencapsulated cells, maintained at 4 ℃ in sour cherry juice, showed 1.31, 2.13, 2.37 and 2.19, 2.46, 3.26 log CFU/mL reduction after exposure to similar pH conditions, respectively. The number of free and encapsulated probiotic cells after incubation in simulated gastric and gastrointestinal fluids was 5.86 and 4.81 and 8.05 and 6.61 log CFU/mL, respectively. The sensory attributes of probiotic sour cherry juice samples containing encapsulated cells were better than those fortified with free probiotics.


Assuntos
Bebidas/microbiologia , Enterococcus faecium/fisiologia , Viabilidade Microbiana , Probióticos , Alginatos , Composição de Medicamentos , Conservação de Alimentos , Frutas , Suco Gástrico , Concentração de Íons de Hidrogênio , Lactobacillus/fisiologia , Prunus avium , Sensação , Termotolerância
17.
Can J Microbiol ; 65(3): 175-184, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30395485

RESUMO

Enterococcus faecium WEFA23 is a potential probiotic strain isolated from Chinese infant feces. In this study, the antagonistic activity of E. faecium WEFA23 on adhesion to pathogens was investigated. Enterococcus faecium WEFA23 was able to compete, exclude, and displace the adhesion of Escherichia coli O157:H7, Salmonella Typhimurium ATCC 13311, Listeria monocytogenes CMCC54007, Staphylococcus aureus CMCC26003, and Shigella sonnei ATCC 25931 to Caco-2 cells. Among them, L. monocytogenes achieved the strongest inhibition rate in both competition and displacement assays. Those anti-adhesion capacities were related to the bacterial physicochemical properties (hydrophobicity, auto-aggregation, and co-aggregation) of the bacterial surface. For L. monocytogenes, the anti-adhesion capacity was affected by the heat treatment, cell density, and growth phase of E. faecium WEFA23; 108 colony-forming units of viable cells per millilitre at the stationary phase exhibited the strongest anti-adhesion activity. In addition, removal of S-layer proteins of E. faecium WEFA23 by treatment with 5 mol/L LiCl significantly decreased its adhesion capacity, and those S-layer proteins were able to compete, displace, and exclude L. monocytogenes at different levels. Both cells and S-layer proteins of E. faecium WEFA23 significantly reduced the apoptosis of Caco-2 cells induced by L. monocytogenes, which was mediated by caspase-3 activation. This study might be helpful in understanding the anti-adhesion mechanism of probiotics against pathogens.


Assuntos
Antibiose , Enterococcus faecium/fisiologia , Glicoproteínas de Membrana/metabolismo , Probióticos/farmacologia , Apoptose , Aderência Bacteriana , Células CACO-2 , Escherichia coli O157/patogenicidade , Humanos , Listeria monocytogenes/patogenicidade , Salmonella typhimurium/patogenicidade , Shigella sonnei/patogenicidade , Staphylococcus aureus/patogenicidade
18.
J Dairy Sci ; 102(1): 77-86, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30447977

RESUMO

Carriers with inoculated microorganisms are often used to validate low-moisture food safety interventions. In this study, we evaluated dry inoculation methods using silicon dioxide (SiO2) and a small portion of nonfat milk powder (NFMP) as dry carriers for NFMP. Silicon dioxide was characterized by vapor sorption analysis. One milliliter of inoculum of a 5-strain Salmonella cocktail (serovars Agona, Reading, Tennessee, Montevideo, and Mbandaka) or Enterococcus faecium NRRL B-2354 was inoculated onto 1 g of SiO2 or 10 g of NFMP as carriers. Both inoculated carriers were air-dried for 72 h [22°C, relative humidity (RH) ∼30%], equilibrated to water activity (aw) 0.25 ± 0.02 (24 h at 22°C, RH 25%), and mixed with preconditioned NFMP (aw = 0.25 ± 0.02) to reach an inoculation level of 8.2 ± 0.2 log cfu/g. Inoculated NFMP was stored at 22°C, RH 25%, and its bacterial populations were monitored for 30 d. Both sets in equilibrated NFMP were subjected to isothermal treatments in closed aluminum cells at 85, 90, and 95°C. Silicon dioxide maintained moisture content (0.29 ± 0.03%, dry basis) at different water activities. The NFMP inoculated with both carriers exhibited stable bacterial populations over 30 d at 22°C. Strains in NFMP inoculated with SiO2 showed equal or higher D-values but equal z-values compared with those inoculated with a small portion of NFMP. Enterococcus faecium exhibited comparable thermal resistance to Salmonella under all tested conditions. This study supports E. faecium as a Salmonella surrogate in thermal processing of NFMP and the use of SiO2 to inoculate NFMP.


Assuntos
Enterococcus faecium/fisiologia , Microbiologia de Alimentos , Leite/química , Salmonella/fisiologia , Dióxido de Silício/administração & dosagem , Animais , Contagem de Colônia Microbiana , Manipulação de Alimentos/métodos , Temperatura Alta , Leite/microbiologia , Pós , Dióxido de Silício/análise , Dióxido de Silício/química , Fatores de Tempo , Água/análise , Água/química
19.
PLoS One ; 13(6): e0199710, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29953486

RESUMO

Enterococci represent one of the microbial world's most challenging enigmas. Colonization of the gastrointestinal tract (GIT) of high-risk/immunocompromised patients by enterococci exhibiting resistance to vancomycin (VRE) can lead to life-threating infections, including bloodstream infections and endocarditis. Decolonization of VRE from the GIT of high-risk patients represents an alternative method to suppress the risk of the infection. It could be considered as a preventative measure to protect against VRE infections in high-risk individuals. Though multiple agents (ramoplanin and bacitracin) have been evaluated clinically, no drugs are currently approved for use in VRE decolonization of the GIT. The present study evaluates ebselen, a clinical molecule, for use as a decolonizing agent against VRE. When evaluated against a broad array of enterococcal isolates in vitro, ebselen was found to be as potent as linezolid (minimum inhibitory concentration against 90% of clinical isolates tested was 2 µg/ml). Though VRE has a remarkable ability to develop resistance to antibacterial agents, no resistance to ebselen emerged after a clinical isolate of vancomycin-resistant E. faecium was serially-passaged with ebselen for 14 days. Against VRE biofilm, a virulence factor that enables the bacteria to colonize the gut, ebselen demonstrated the ability to both inhibit biofilm formation and disrupt mature biofilm. Furthermore, in a murine VRE colonization reduction model, ebselen proved as effective as ramoplanin in reducing the bacterial shedding and burden of VRE present in the fecal content (by > 99.99%), cecum, and ileum of mice. Based on the promising results obtained, ebselen warrants further investigation as a novel decolonizing agent to quell VRE infection.


Assuntos
Azóis/farmacologia , Biofilmes/efeitos dos fármacos , Enterococcus faecium , Infecções por Bactérias Gram-Positivas , Compostos Organosselênicos/farmacologia , Resistência a Vancomicina/efeitos dos fármacos , Fatores de Virulência/metabolismo , Animais , Biofilmes/crescimento & desenvolvimento , Enterococcus faecium/patogenicidade , Enterococcus faecium/fisiologia , Feminino , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Camundongos
20.
J Dairy Sci ; 101(9): 7757-7767, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29935822

RESUMO

Enterococcus faecium WEFA23 is a potential probiotic strain from Chinese infants with the ability to decrease cholesterol levels. Aiming to explore the mechanism of E. faecium WEFA23 in lowering cholesterol in vivo, we examined the gene transcriptions related to cholesterol metabolism, the composition of bile acids in feces, the synthesis of trimethylamine N-oxide (TMAO) in liver, and the composition of the gut microbiota of rats. We found that E. faecium WEFA23 enhanced the synthesis of bile acids by promoting cholesterol excretion, upregulating the genes transcript level relevant to cholesterol decomposition and transportation, and downregulating the genes involved in cholesterol synthesis. In addition, E. faecium WEFA23 not only downregulated the transcript levels of farnesoid X receptor and fibroblast growth factor 15 as well as flavin-containing monooxygenase 3, but also decreased the TMAO production followed by increasing the CYP7A1 transcript level. Furthermore, when orally administered to rats for 35 d, E. faecium WEFA23 improved the gut microbiota diversity of rats fed a high-fat diet. Therein, the ratio of Bacteroidetes to Firmicutes and the abundance of Rikenellaceae increased, whereas the number of Veillonellaceae decreased. These results suggest that reduction of cholesterol level by E. faecium WEFA23 might be related to the changes in the gut microbiota. Our finding provides important information on lowering cholesterol by E. faecium and reveals that Enterococcus spp. might have the potential to decrease the TMAO level.


Assuntos
Colesterol 7-alfa-Hidroxilase/genética , Enterococcus faecium/fisiologia , Microbioma Gastrointestinal , Probióticos/administração & dosagem , Animais , Colesterol , Dieta Hiperlipídica , Hiperlipidemias , Fígado , Ratos
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