Tellurite Resistance in Shiga Toxin-Producing \u3ci\u3eEscherichia coli \u3c/i\u3e

Potassium tellurite ( K2TeO3) is an effective selective agent for O157:H7 Shiga toxin-producing Escherichia coli (STEC), whereas tellurite resistance in non-O157 STEC is variable with information on O45 minimal. High-level K2TeO3 resistance in STEC is attributable to the ter gene cluster with terD an indicator of the cluster’s presence. Polymerase chain reactions for terD and K2TeO3 minimum inhibitory concentration (MIC) determinations in broth cultures were conducted on 70 STEC and 40 non-STEC control organisms. Sixty-six STEC strains (94.3%) were terD+ compared to 28 control organisms (70.0%; P \u3c 0.001). The prevalence of terD in O103 STEC strains was 70%, whereas in all other serogroups it was ≥ 90%. The K2TeO3 geometric mean MIC ranking for STEC serogroups from highest to lowest was O111 \u3e O26 \u3e O145 \u3e O157 \u3e O103 \u3e O12 1 = O45. The K2TeO3 geometric mean MIC was significantly higher in terD+ than in terD− STEC, but not in terD+ versus terD− control strains. Resistance to K2TeO3 (MIC ≥ 25 mg/L) was exhibited by 65/66 terD+ and 0/4 terD− STEC strains, compared to 12/28 terD+ and 8/12 terD− control strains. These results confirm previous studies showing the significantly higher prevalence of the ter gene cluster in STEC strains, and the relationship between these genes and K2TeO3 resistance in STEC and especially intimin (eae)-positive STEC, in contrast to non-STEC organisms. O45 and O121 STEC, although frequently terD positive, on average had significantly lower levels of K2TeO3 resistance than O26, O111, and O145 STEC

Changes in Health-Related Fitness of College Females During a One-Semester Activity Course

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Investigation of congestive heart failure in beef cattle in a feedyard at a moderate altitude in western Nebraska

Right-sided congestive heart failure (brisket disease) commonly occurs in cattle raised at elevations \u3e2,500– 3,500 m. We investigated clinical cases resembling brisket disease at a western Nebraska feedyard at a moderate altitude (1,369 m). Over a 15-mo period (2009–2010), we examined 17 cases (16 steers and 1 heifer), all purebred Angus. All animals had clinical right-sided heart failure: brisket and ventral abdominal edema, and severe chronic passive congestion of the liver. Gross examination confirmed right ventricular hypertrophy (left ventricle plus septum: right ventricle weight ratio mean: 1.33 vs. 2.8–4.0 reference interval). Microscopically, all 17 cases had interstitial fibrosis (mean score: 2.4 ± 0.8) and 6 had replacement fibrosis of the right ventricle, whereas 14 had interstitial fibrosis (mean score: 1.2 ± 0.2) and 0 had replacement fibrosis of the left ventricle. Lesions of arteriosclerosis were seen in 9 of 16 cases in 51 of 571 (8.9%) right ventricular coronary arteries, and in 10 of 16 cases in 52 of 366 (14.2%) left ventricular coronary arteries. The probability of coronary arteriosclerosis was greater in papillary ventricular muscle (OR = 11.3; p \u3c 0.0001), left ventricle (OR = 4.8; p \u3c 0.0001), and larger arteries (OR = 1.01; p \u3c 0.0001). Pulmonary arteries and arterioles had lesions compatible with hypoxia-induced pulmonary hypertension. We hypothesize that moderate hypobaric conditions significantly contributed to disease in cattle genetically predisposed to hypoxia-induced pulmonary hypertension. Adiposity, coronary arteriosclerosis, and left ventricular fibrosis may have contributed to the condition; however, the cattle died prior to development of advanced obesity

Intimate Attachment of Escherichia coli O157:H7 to Urinary Bladder Epithelium in the Gnotobiotic Piglet Model

Enterohemorrhagic Escherichia coli (EHEC), a pathogenic subset of Shiga toxin-producing E. coli (STEC), is an important cause of hemorrhagic colitis and hemolytic–uremic syndrome (HUS), and a rare cause of urinary tract infections (UTIs) with associated HUS. EHEC strains attach intimately to intestinal epithelium with formation of actin pedestals (attaching-effacing (A/E) lesions); however, the mechanism of EHEC attachment to the uroepithelium is unknown. We conducted a retrospective study on archived urinary bladder specimens from gnotobiotic piglets that naturally developed cystitis associated with EHEC O157:H7 infection following oral inoculation and fecal shedding. Paraffin-embedded bladder tissues from three piglets with cystitis and immunohistochemical evidence of EHEC O157:H7 adherence to the uroepithelium were processed for and examined by transmission electron microscopy. EHEC O157:H7 bacteria were found in one of three piglets, intimately attached to pedestals on the apical surfaces of the superficial urothelium (umbrella cells). Cystitis was significantly associated with the length of survival of the piglets post-inoculation (p = 0.0339; estimated odds ratio = 2.6652). This is the first report of E. coli causing A/E-like lesions in the uroepithelium, and also evidence of the utility of the gnotobiotic piglet as a model for studies of the pathogenesis of EHEC UTIs

Effect of \u3ci\u3eLactobacillus acidophilus\u3c/i\u3e Strain N P51 on\u3ci\u3e Escherichia coli \u3c/i\u3e0157:H7 Fecal Shedding and Finishing Performance in Beef Feedlot Cattle

A 2-year study was conducted during the summer months (May to September) to test the effectiveness of feeding Lactobacillus acidophilus strain NP51 on the proportion of cattle shedding Escherichia coli 0157:H7 in the feces and evaluate the effect of the treatment on finishing performance. Steers (n = 448) were assigned randomly to pens, and pens of cattle were assigned randomly to NP5 1 supplementation or no supplementation (control). NP5 1 products were mixed with water and applied as the feed was mixed daily in treatment-designated trucks at the rate of l09 CFU per steer. Fecal samples were collected (n = 3,360) from the rectum from each animal every 3 weeks, and E. coli 0157:H7 was isolated by standard procedures, using selective enrichment, immunomagnetic separation, and PCR confirmation. The outcome variable was the recovery of E. coli 0157:H7 from feces, and was modeled using logistic regression accounting for year, repeated measures of pens of cattle, and block. No significant differences were detected for gain, intakes, or feed efficiency of control or NP51-fed steers. The probability for cattle to shed E. coli 0157:H7 varied significantly between 2002 and 2003 (P = 0.004). In 2002 and 2003, the probability for NP5 1-treated steers to shed E. coli 0157:H7 over the test periods was 13 and 21 %, respectively, compared with 21 and 28% among controls. Over the 2 years, NP51-treated steers were 35% less likely to shed E. coli 0157: H7 than were steers in untreated pens (odds ratio = 0.58, P = 0.008). This study is consistent with previous reports that feeding NP51 is effective in reducing E. coli 0157:H7 fecal shedding in feedlot cattle

METHOD TO DETECT THE PRESENCE OF A MICROORGANISM OR AGENT IN AN ANIMAL

The present invention provides a method to detect the presence of a microorganism or agent in an animal. The method encompasses placement of devices at various locations where the animal resides so as to induce the animal to initiate contact with the device. As a result of this contact, the animal deposits various microorganisms and agents on the device. The device is then tested for the presence of the particular microorganism or agent of interest

Haemorrhagic Colitis Associated with Enterohaemorrhagic \u3ci\u3eEscherichia coli\u3c/i\u3e O165:H25 Infection in a Yearling Feedlot Heifer

Introduction: Enterohaemorrhagic Escherichia coli (EHEC) cause haemorrhagic colitis and haemolytic uraemic syndrome in humans. Although EHEC infection typically results in haemorrhagic colitis in all ages of human patients, in cattle it is usually limited to 1- to 5-week-old nursing calves. Case Presentation: A 1-year-old feedlot beef heifer was moribund with neurological signs and bloody diarrhoea. At necropsy, the colonic mucosa contained multiple grossly visible haemorrhagic erosions, each measuring \u3c1 mm in diameter. Histologically, foci corresponding to the gross erosions had E. coli O165 antigen-positive bacterial rods adherent to the apical surfaces of degenerate and necrotic colonic mucosal epithelial cells in association with attaching and effacing lesions, and also within cytoplasmic vacuoles in some of these cells. An E. coli O165:H25 strain was isolated from the colonic mucosal tissue, and by microarray analysis was found to contain virulence genes corresponding to type III secretion system (T3SS) structure and regulation (cesD, cesT, escD, escF, escN/escV, escR, escT, ler, sepL, sepQ), T3SS effectors (espA, espB, espC, espD, espD, espF, espH, espJ, nleB, nleC, nleD, nleH, tir), serine proteases (eatA, espC, espP), Shiga toxin (stx2), EHEC-haemolysin (ehxA), and adhesins [intimin-ε (eae-ε), type 1 fimbria (fimA, fimB, fimH), type IV pili (pilA, pilB, pilC, pilM, pilP, pilQ) and non-fimbrial adhesin (efa1/lifA)]. Conclusion: To the best of our knowledge, this is the first report of disease in cattle associated with EHEC O165:H25 infection, the oldest bovine EHEC disease case with isolation of the pathogen and the first bovine case to demonstrate grossly evident, haemorrhagic, colonic mucosal erosions associated with EHEC infection

Haemorrhagic Colitis Associated with Enterohaemorrhagic \u3ci\u3eEscherichia coli\u3c/i\u3e O165:H25 Infection in a Yearling Feedlot Heifer

Introduction: Enterohaemorrhagic Escherichia coli (EHEC) cause haemorrhagic colitis and haemolytic uraemic syndrome in humans. Although EHEC infection typically results in haemorrhagic colitis in all ages of human patients, in cattle it is usually limited to 1- to 5-week-old nursing calves. Case Presentation: A 1-year-old feedlot beef heifer was moribund with neurological signs and bloody diarrhoea. At necropsy, the colonic mucosa contained multiple grossly visible haemorrhagic erosions, each measuring \u3c1 mm in diameter. Histologically, foci corresponding to the gross erosions had E. coli O165 antigen-positive bacterial rods adherent to the apical surfaces of degenerate and necrotic colonic mucosal epithelial cells in association with attaching and effacing lesions, and also within cytoplasmic vacuoles in some of these cells. An E. coli O165:H25 strain was isolated from the colonic mucosal tissue, and by microarray analysis was found to contain virulence genes corresponding to type III secretion system (T3SS) structure and regulation (cesD, cesT, escD, escF, escN/escV, escR, escT, ler, sepL, sepQ), T3SS effectors (espA, espB, espC, espD, espD, espF, espH, espJ, nleB, nleC, nleD, nleH, tir), serine proteases (eatA, espC, espP), Shiga toxin (stx2), EHEC-haemolysin (ehxA), and adhesins [intimin-ε (eae-ε), type 1 fimbria (fimA, fimB, fimH), type IV pili (pilA, pilB, pilC, pilM, pilP, pilQ) and non-fimbrial adhesin (efa1/lifA)]. Conclusion: To the best of our knowledge, this is the first report of disease in cattle associated with EHEC O165:H25 infection, the oldest bovine EHEC disease case with isolation of the pathogen and the first bovine case to demonstrate grossly evident, haemorrhagic, colonic mucosal erosions associated with EHEC infection

Membrane Insertion for the Detection of Lipopolysaccharides: Exploring the Dynamics of Amphiphile-in-Lipid Assays

Shiga toxin-producing Escherichia coli is an important cause of foodborne illness, with cases attributable to beef, fresh produce and other sources. Many serotypes of the pathogen cause disease, and differentiating one serotype from another requires specific identification of the O antigen located on the lipopolysaccharide (LPS) molecule. The amphiphilic structure of LPS poses a challenge when using classical detection methods, which do not take into account its lipoglycan biochemistry. Typically, detection of LPS requires heat or chemical treatment of samples and relies on bioactivity assays for the conserved lipid A portion of the molecule. Our goal was to develop assays to facilitate the direct and discriminative detection of the entire LPS molecule and its O antigen in complex matrices using minimal sample processing. To perform serogroup identification of LPS, we used a method called membrane insertion on a waveguide biosensor, and tested three serogroups of LPS. The membrane insertion technique allows for the hydrophobic association of LPS with a lipid bilayer, where the exposed O antigen can be targeted for specific detection. Samples of beef lysate were spiked with LPS to perform O antigen specific detection of LPS from E. coli O157. To validate assay performance, we evaluated the biophysical interactions of LPS with lipid bilayers both in- and outside of a flow cell using fluorescence microscopy and fluorescently doped lipids. Our results indicate that membrane insertion allows for the qualitative and reliable identification of amphiphilic LPS in complex samples like beef homogenates. We also demonstrated that LPS-induced hole formation does not occur under the conditions of the membrane insertion assays. Together, these findings describe for the first time the serogroup-specific detection of amphiphilic LPS in complex samples using a membrane insertion assay, and highlight the importance of LPS molecular conformations in detection architectures

DJ-1 is not a deglycase and makes a modest contribution to cellular defense against methylglyoxal damage in neurons

Human DJ-1 is a cytoprotective protein whose absence causes Parkinson\u27s disease and is also associated with other diseases. DJ-1 has an established role as a redox-regulated protein that defends against oxidative stress and mitochondrial dysfunction. Multiple studies have suggested that DJ-1 is also a protein/nucleic acid deglycase that plays a key role in the repair of glycation damage caused by methylglyoxal (MG), a reactive α-keto aldehyde formed by central metabolism. Contradictory reports suggest that DJ-1 is a glyoxalase but not a deglycase and does not play a major role in glycation defense. Resolving this issue is important for understanding how DJ-1 protects cells against insults that can cause disease. We find that DJ-1 reduces levels of reversible adducts of MG with guanine and cysteine in vitro. The steady-state kinetics of DJ-1 acting on reversible hemithioacetal substrates are fitted adequately with a computational kinetic model that requires only a DJ-1 glyoxalase activity, supporting the conclusion that deglycation is an apparent rather than a true activity of DJ-1. Sensitive and quantitative isotope-dilution mass spectrometry shows that DJ-1 modestly reduces the levels of some irreversible guanine and lysine glycation products in primary and cultured neuronal cell lines and whole mouse brain, consistent with a small but measurable effect on total neuronal glycation burden. However, DJ-1 does not improve cultured cell viability in exogenous MG. In total, our results suggest that DJ-1 is not a deglycase and has only a minor role in protecting neurons against methylglyoxal toxicity