for a one-Health investigation of antimicrobial resistance (AMR) in Enterococcus spp., isolates from humans and beef cattle along with abattoirs, manured fields, natural streams, and wastewater from both urban and cattle feedlot sources were collected over two years. Species identification of Enterococcus revealed distinct associations across the continuum. Of the 8430 isolates collected, Enterococcus faecium and Enterococcus faecalis were the main species in urban wastewater (90%) and clinical human isolates (99%); Enterococcus hirae predominated in cattle (92%) and feedlot catch-basins (60%), whereas natural streams harbored environmental Enterococcus spp. Wholegenome sequencing of E. faecalis (n = 366 isolates) and E. faecium (n = 342 isolates), revealed source clustering of isolates, indicative of distinct adaptation to their respective environments. phenotypic resistance to tetracyclines and macrolides encoded by tet(M) and erm(B) respectively, was prevalent among Enterococcus spp. regardless of source. for E. faecium from cattle, resistance to β-lactams and quinolones was observed among 3% and 8% of isolates respectively, compared to 76% and 70% of human clinical isolates. clinical vancomycin-resistant E. faecium exhibited high rates of multi-drug resistance, with resistance to all β-lactam, macrolides, and quinolones tested. Differences in the AMR profiles among isolates reflected antimicrobial use practices in each sector of the One-Health continuum. Public concern for antimicrobial use (AMU) and resistance (AMR) in livestock is increasing, as is continuing pressure for industries and governments to address these concerns. Science-based and epidemiologically sound research is critical to drive policy, communication, legislation, and inform consumer choices. To effectively investigate the current state of antimicrobial resistance, holistic One Health approaches are required to determine correlation between AMU and AMR across the human-agriculture-environment continuum. The genus Enterococcus is ubiquitous in nature and member species can be found in a range of habitats including soils, sediments, freshwater, marine water, beach sand, and a variety of plants 1,2. Enterococcus spp. are also common members of the normal gastrointestinal (GI) flora of both livestock and humans 3 , with their concentrations in human and animal feces typically ranging from 10 3-10 7 cells per gram 4-6. Enterococcus spp. are also commonly isolated from water contaminated by sewage or fecal wastes, and are widely used as bacteriological
Inflammation plays a central pathogenic role in the initiation and progression of coronary atheroma and its clinical consequences.
It is well recognised that oestrogens possess vasodilatory properties, and similar responses to testosterone have been demonstrated. However, vasomotor effects of other steroid hormones have not been well described. Direct comparisons of the relative vasoactivity of different steroid hormones in different vascular beds in male and female genders have not been made. Coronary and pulmonary arteries from adult Wistar rats were mounted in a wire myograph, loaded to 100 and 17 mmHg respectively, maximally pre-contracted with 1 x 10(-4) M prostaglandin-F-2-alpha, and dose response curves to 1 x 10(-6) to 1 x 10(-3) or 3 x 10(-3) M of 17 beta-oestradiol, testosterone, progesterone, and cortisol dissolved in water were constructed. Addition of each steroid hormone caused acute, dose dependent dilatation in coronary and pulmonary vessels. In coronary arteries the order of activity was testosterone > progesterone > 17 beta-oestradiol > cortisol, p < 0.001. In pulmonary arteries, the order of activity was progesterone > testosterone > cortisol > 17 beta-oestradiol, p < 0.001. Pulmonary arteries from male animals were more sensitive to the effects of testosterone than those from female animals, p = 0.003, whereas coronary arteries from female animals were more sensitive to the effects of 17 beta-oestradiol than those from male animals, p < 0.001. We have demonstrated significant differences in the in vitro vasomotor effects of different steroid hormones in two distinct vascular beds. Gender differences in vasomotor responses to steroid hormones may play a role in the aetiology of vasospastic diseases.
Background-Research supports a beneficial effect of physiological testosterone on cardiovascular disease. The mechanisms by which testosterone produces these effects have yet to be elucidated. The testicular feminized (Tfm) mouse exhibits a nonfunctional androgen receptor and low circulating testosterone concentrations. We used the Tfm mouse to determine whether testosterone modulates atheroma formation via its classic signaling pathway involving the nuclear androgen receptor, conversion to 17-estradiol, or an alternative signaling pathway. Methods and Results-Tfm mice (nϭ31) and XY littermates (nϭ8) were separated into 5 experimental groups. Each group received saline (Tfm, nϭ8; XY littermates, nϭ8), physiological testosterone alone (Tfm, nϭ8), physiological testosterone in conjunction with the estrogen receptor ␣ antagonist fulvestrant (Tfm, nϭ8), or physiological testosterone in conjunction with the aromatase inhibitor anastrazole (Tfm, nϭ7). All groups were fed a cholesterol-enriched diet for 28 weeks. Serial sections from the aortic root were examined for fatty streak formation. Blood was collected for measurement of total cholesterol, high-density lipoprotein cholesterol (HDLC), non-HDLC, testosterone, and 17-estradiol. Physiological testosterone replacement significantly reduced fatty streak formation in Tfm mice compared with placebo-treated controls (0.37Ϯ0.07% versus 2.86Ϯ0.39%, respectively; PՅ0.0001). HDLC concentrations also were significantly raised in Tfm mice receiving physiological testosterone replacement compared with those receiving placebo (2.81Ϯ0.30 versus 2.08Ϯ0.09 mmol/L, respectively; Pϭ0.05). Cotreatment with either fulvestrant or anastrazole completely abolished the improvement in HDLC. Conclusion-Physiological testosterone replacement inhibited fatty streak formation in the Tfm mouse, an effect that was independent of the androgen receptor. The observed increase in HDLC is consistent with conversion to 17-estradiol.
Objective: In the absence of widely available measures of determining free and/or bioavailable testosterone (BioT) physicians may use formulae such as the free androgen index (FAI) to estimate free testosterone. We compared the efficacy of calculated markers of androgen status in predicting serum BioT and hypogonadism. Design: Total testosterone (TT), sex hormone binding globulin (SHBG) and BioT were determined in a large cohort of men. Comparison of calculated androgen levels was performed following endocrine assessment. Methods: TT and SHBG were determined by ELISA, and BioT was determined by ammonium sulphate precipitation. From these data we calculated FAI and free testosterone using two other published formulae -FTnw (free testosterone as calculated by the method of Nanjeee and Wheeler) and FTv (free testosterone as calculated by the method of Vermeulen). A novel formula was derived to calculate BioT from given levels of TT and SHBG (BTcalculated). The ability of the methods (FAI, FTnw, FTv, BTcalc) to predict BioT were compared using regression analysis. The ability of these markers of androgen status to predict biochemical hypogonadism was compared using area under receiver operator curve (auROC). Results: The equation derived from our data was the best predictor of BioT (R 2 ¼ 0.73, P , 0.0001) although TT was also a good marker (R 2 ¼ 0.68, P ¼ 0.0001). In the determination of hypogonadism, of all currently available formulae none were better that the TT (
Recent clinical studies have reported that testosterone therapy reduces myocardial ischaemia in men with coronary artery disease, and the beneficial modulation of coronary vascular tone by testosterone has been proposed as an effector mechanism. Maintenance of a correct response to vasoconstrictive and vasodilatory agents is essential in the control of vascular tone. Endothelial dysfunction, most commonly manifested through an elevation in vascular tone, is implicated as an initiating factor in conditions such as hypertension and atherosclerosis. Increased sensitivity to vasoconstrictive stimuli is also proposed in the development of heart failure and hypertensive vascular remodelling, while increased coronary vascular reactivity to vasoconstrictive factors is likely further to restrict coronary blood flow through the partially occluded atherosclerotic vessel. Reduced vasodilatation and enhanced vasoconstriction can also lead to vasospasm and exacerbation of anginal symptoms. Testosterone is well known to elicit direct vasodilatation, but its influence upon responses induced by other vasoactive agents is less coherent, and may depend upon the underlying pathogenic process or gender. The aim of this review is to present the data obtained from both the patient and animal studies conducted to date, to ascertain any influence testosterone may have upon the regulation of vascular tone.
Groups of 25 carcasses were obtained by random selection of carcasses at the end of each of eight commercial processes for the dressing or cooling of carcasses. Samples were collected from six groups of pig or beef carcasses by excision or swabbing with sponge, gauze, or cotton wool, with one sample obtained by each of the four methods from a separate, randomly selected site on each carcass. Total aerobic counts, coliforms, and Escherichia coli from each sample were enumerated. Values for the mean log10, log10 mean, and log10 total numbers recovered were calculated for each set of total aerobic counts. Those statistics indicated that the numbers of bacteria recovered by excision or swabbing with sponge or gauze were similar, while the numbers recovered by swabbing with cotton wool were at the lower end of or below the range of the numbers recovered by the other methods. The numbers of coliforms or E. coli recovered from carcasses by sampling areas up to 100 cm2 were too few for the estimation of log mean numbers. Sampling of two groups of carcasses by swabbing with gauze indicated that each 10-fold increase in the area sampled, from 10 to 1,000 cm2, approximately doubled the number of samples from which coliforms or E. coli were recovered. Sampling of six groups of carcasses from one process indicated that the sizes of swabs and volumes of diluent used for processing swabs did not have to be increased proportionally to the area of carcass surface sampled to recover numbers of E. coli proportional to the sampled area. It therefore appears that carcass sampling techniques can be varied widely without compromising the recovery of bacteria, and that the relative efficiencies with which bacteria are recovered by different techniques can be assessed by sampling each carcass in a group of 25 by each of the methods to be compared.
Objective: Testicular feminised (Tfm) mice express a non-functional androgen receptor, and also have reduced levels of circulating testosterone. Recent studies support a cardio-protective role for testosterone since it elicits systemic and pulmonary vasodilatation. The aim of the present study was to determine whether androgen insensitivity and hypotestosteronaemia in the Tfm mouse are associated with abnormal vascular reactivity or hormone status. Methods: Adult male Tfm and littermate control mice were killed and the blood collected. Femoral (diameter range = 183 -508 mm) and pulmonary (diameter range = 320-816 mm) arteries were dissected and loaded in either a wire or pressure myograph, at 100 mmHg or 17.5 mmHg respectively. Pharmacological assessment of the vasoreactivity to potassium chloride (KCl, 80 mmol/l) and either noradrenaline (NA, 1 nmol/l -100 mmol/l) and acetylcholine (ACh, 0.1 -100 mmol/l) or testosterone (1 nmol/l -100 mmol/l) was then made. Results: Tfm mice had reduced levels of testosterone (1.8^0.3 nmol/l) compared with controls (9.3^2.0 nmol/l, P , 0:001Þ and elevated levels of cholesterol (3.6+0.1 mmol/l) compared with controls ð3:2 þ 0:1 mmol=l; P , 0:05Þ: Femoral arteries from Tfm mice exhibited reduced vasoconstriction to 80 mmol/l KCl ð3:27^0:23 mN=mmÞ compared with vessels from controls ð4:44^0:41 mN=mm; P , 0:05Þ; and reduced endothelial-dependent vasodilatation to 0.1-100 mmol/l ACh ð23:3^3:6% relaxation) compared with vessels from controls ð41:6^5:4% relaxation, P , 0:05Þ: Vasoconstriction to NA (1 nmol/l -100 mmol/l) and vasodilatation to testosterone were unaffected. Conclusions: Androgen receptor deficiency and hypotestosteronaemia in the Tfm mouse reduced endothelial function and impaired voltage-operated calcium channel activity, which may pre-dispose to cardiovascular disease. Testosterone-induced vasodilatation was unaffected, demonstrating no involvement of the androgen receptor in this response.
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