AA amyloidosis (AAA) is a disease known as amyloid arthropathy in chicken, which represents substantial economic losses, in addition to welfare concerns. Enterococcus faecalis (E. faecalis) is the major pathogen found in field outbreaks of amyloid arthropathy and its specific association with this disease has been extensively confirmed. The following review discusses the sequence types of E. faecalis associated with AAA that have been identified and characterised both poultry and humans and provide different hypotheses and theories about pathogenesis and transmission of this disease. This article covers the pathology both in field and induced cases of avian amyloidosis and concludes with approaches for a possible treatment, needs for further research and future perspectives. This paper is a consolidation of current knowledge on AAA in chickens which has been obtained over the last twenty years.

In vivo studies have provided evidence that micro-organisms have important roles in immunological, digestive and respiratory functions, conferring health benefits on the host. Several in vitro methods have been advised for the initial screening of microbes with potential health effects. The objective of the present study was to employ such in vitro methodology to characterise different strains of Enterococcus faecalis. The characteristics of a commercial product marketed as a probiotic, Symbioflor-1 (Symbiopharm), were compared with the characteristics of both pathogenic and commensal strains. Tolerance towards low pH and viability after exposure to human gastric and duodenal juices were assayed. Symbioflor-1 was the most susceptible strain to these treatments when compared with the other E. faecalis strains. Furthermore, Symbioflor-1 exhibited the lowest adhesion capacity to intestinal epithelial cells (IEC) and mucus. Competitive binding studies using heparin indicated that glycosaminoglycans might be involved in the adhesion to IEC, but also that differences in these putative bacteria–host interactions do not cause the relative low adhesion capacity of Symbioflor-1. Maturation of dendritic cells (DC) after exposure to bacteria was assayed as an indication of an immunomodulatory effect. All strains induced a moderate elevation of the DC maturation markers CD83 and CD86; however, no strain-specific differences were detected. Correlations between in vitro and in vivo studies are discussed. Although in vitro assaying is a rational starting point for the selection of microbes with a potential health benefit, it is emphasised that human clinical trials are the definite tool for establishing probiotic status.

Biofilms are assemblages of microorganisms and their associated extracellular products at an interface and typically with an abiotic or biotic surface. The study of the morphology of biofilms is important because they are associated with processes of biofouling, corrosion, catalysis, pollutant transformation, dental caries, drug resistance, and so forth. In the literature, biofilms have been examined by atomic force microscopy (AFM), which has proven to be a potent tool to study different aspects of the biofilm development on solid surfaces. In this work, we used AFM to investigate topographical changes during the development process of Enterococcus faecalis biofilms, which were generated on sterile cellulose nitrate membrane (CNM) filters in brain heart infusion (BHI) broth agar blood plates after 24, 36, 72, 192, and 360 h. AFM height images showed topographical changes due to biofilm development, which were used to characterize several aspects of the bacterial surface, such as the presence of extracellular polymeric substance, and the biofilm development stage. Changes in the development stage of the biofilm were shown to correlate with changes in the surface roughness as quantified through the mean roughness.

We have evaluated the changes in arterial blood pressure caused in spontaneously hypertensive rats (SHR) by long-term intake of an Enterococcus faecalis CECT 5728-fermented milk with significant angiotensin-converting enzyme (ACE)-inhibitory activity. After being weaned, male 3-week-old SHR were randomized into five groups. Until the 20th week of life, rats in each group were given one of the following drinking fluids: tap water (negative control 1), a fermented milk without ACE-inhibitory activity (negative control 2), captopril (100 mg/kg) (positive control), the E. faecalis CECT 5728-fermented milk that had significant ACE-inhibitory activity, or Ca-enriched E. faecalis CECT 5728-fermented milk. Animals in the different groups were then given tap water as drinking fluid from the 20th to 25th week of life. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly in the rats, from the 6th to 25th week of life, by the tail-cuff method. A definite decrease in SBP and DBP could be observed in the rats treated with captopril and also in the rats that received the E. faecalis CECT 5728-fermented milks. The greatest antihypertensive effect was observed when the pharmacological treatment was administered. The effect of the Ca-enriched fermented milk was slightly more accentuated and more constant than the effect of the E. faecalis CECT 5728-fermented milk that had not been enriched in Ca. SBP and DBP increased in the treated SHR when the corresponding antihypertensive treatment was removed. Fermentation of milk with E. faecalis CECT 5728 may therefore be a successful strategy to produce a functional food with antihypertensive activity.

The outer surfaces of three microorganisms, Giardia lamblia, Enterococcus faecalis, and Proteus mirabilis, were investigated by cryo-immobilization followed by sublimation of extracellular ice and cryocoating with either Pt alone or Pt plus carbon. Cryocoated samples were examined at −125°C in either an in-lens field emission SEM or a below-the-lens field emission SEM. Cryocoating with Pt alone was sufficient for low magnification observation, but attempts to do high-resolution imaging resulted in radiolysis and cracking of the specimen surface. Double coating with Pt and carbon, in combination with high resolution backscatter electron detectors, enabled high-resolution imaging of the glycocalyx of bacteria, revealing a sponge-like network over the surface. High resolution examination of bacterial flagella also revealed a periodic substructure. Common artifacts included radiolysis leading to “cracking” of the surface, and insufficient deposition of Pt resulting in the absence of detectable surface topography.

Since genetically modified (GM) lactic acid bacteria (LAB) might be released in open environments for future nutritional and medical applications, the purpose of this study was to determine an upper limit for the horizontal gene transfer (HGT) in the digestive tract (DT) from Lactococcus lactis carrying heterologous genes (lux genes encoding a bacterial luciferase) to Enterococcus faecalis. Two enterococcal wide host-range conjugative model systems were used: (i) a system composed of a mobilizable plasmid containing the heterologous lux genes and a native conjugative helper plasmid; and (ii) a Tn916-lux transposon. Both systems were tested under the most transfer-prone conditions, i.e. germfree mice mono-associated with the recipient E. faecalis. No transfer was observed with the transposon system. Transfers of the mobilizable plasmid carrying heterologous genes were below 102 transconjugants per g of faeces for a single donor dose and reached between 103 and 104 transconjugants per g of faeces when continuous inoculation of the donor strain was used. Once established in mice, transconjugants persisted at low levels in the mouse DT.