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

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

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

Efficacy of Urtoxazumab (TMA-15 Humanized Monoclonal Antibody Specific for Shiga Toxin 2) Against Post-Diarrheal Neurological Sequelae Caused by \u3ci\u3eEscherichia coli\u3c/i\u3e O157:H7 Infection in the Neonatal Gnotobiotic Piglet Model

Enterohemorrhagic Escherichia coli (EHEC) is the most common cause of hemorrhagic colitis and hemolytic uremic syndrome in human patients, with brain damage and dysfunction the main cause of acute death. We evaluated the efficacy of urtoxazumab (TMA-15, Teijin Pharma Limited), a humanized monoclonal antibody against Shiga toxin (Stx) 2 for the prevention of brain damage, dysfunction, and death in a piglet EHEC infection model. Forty-five neonatal gnotobiotic piglets were inoculated orally with 3 x 109 colony-forming units of EHEC O157:H7 strain EDL933 (Stx1+, Stx2+) when 22–24 h old. At 24 h post-inoculation, piglets were intraperitoneally administered placebo or TMA-15 (0.3, 1.0 or 3.0 mg/kg body weight). Compared to placebo (n = 10), TMA-15 (n = 35) yielded a significantly greater probability of survival, length of survival, and weight gain (

Immunocompromise in Gnotobiotic Pigs Induced by Verotoxin-Producing \u3ci\u3eEscherichia coli\u3c/i\u3e (O111:NM)

A verotoxin-producing Escherichia coli serotype O111:NM strain (strain 10049; verotoxin 1 positive) persistently infected experimentally inoculated gnotobiotic pigs, causing attaching-effacing intestinal lesions and chronic diarrhea. Experiments were performed to determine whether persistent infection might be associated with immunocompromise of the host by this organism. Pigs inoculated with this strain had a significant reduction in peripheral blood lymphocytes and lower antibody titers to sheep erythrocytes compared with control pigs. Compared with pigs given a verotoxin-negative pathogenic strain of the same serotype (O111:NM, strain 2430), pigs inoculated with the verotoxin-positive strain had lower peripheral lymphocyte counts and proliferative responses to concanavalin A, phytohemagglutinin, and pokeweed mitogens. The results of this study suggest that strain 10049 has an immunocompromising effect on gnotobiotic pigs

Immunocompromise in Gnotobiotic Pigs Induced by Verotoxin-Producing \u3ci\u3eEscherichia coli\u3c/i\u3e (O111:NM)

A verotoxin-producing Escherichia coli serotype O111:NM strain (strain 10049; verotoxin 1 positive) persistently infected experimentally inoculated gnotobiotic pigs, causing attaching-effacing intestinal lesions and chronic diarrhea. Experiments were performed to determine whether persistent infection might be associated with immunocompromise of the host by this organism. Pigs inoculated with this strain had a significant reduction in peripheral blood lymphocytes and lower antibody titers to sheep erythrocytes compared with control pigs. Compared with pigs given a verotoxin-negative pathogenic strain of the same serotype (O111:NM, strain 2430), pigs inoculated with the verotoxin-positive strain had lower peripheral lymphocyte counts and proliferative responses to concanavalin A, phytohemagglutinin, and pokeweed mitogens. The results of this study suggest that strain 10049 has an immunocompromising effect on gnotobiotic pigs

Comparison of the Contributions of Heat-Labile Enterotoxin and Heat-Stable Enterotoxin b to the Virulence of Enterotoxigenic \u3ci\u3eEscherichia coli \u3c/i\u3ein F4ac Receptor-Positive Young Pigs

In swine, the most common and severe enterotoxigenic Escherichia coli (ETEC) infections are caused by strains that express K88 (F4)+ fimbriae, heat-labile enterotoxin (LT), heat-stable enterotoxin b (STb), and enteroaggregative E. coli heat-stable toxin 1. Previous studies based on a design that involved enterotoxin genes cloned into a nontoxigenic fimbriated strain have suggested that LT but not STb plays an important role in dehydrating diarrheal disease in piglets study, we compared these two toxins in terms of importance for piglets \u3e1 week old with a study design that involved construction of isogenic single- and double-deletion mutants and inoculation of 9-day-old F4ac receptor-positive gnotobiotic piglets. Based on the postinoculation percent weight change per h and serum bicarbonate concentrations, the virulence of the STb- mutant (ΔestB) did not significantly differ from that of the parent. However, deletion of the LT genes (ΔeltAB) in the STb- mutant resulted in a complete abrogation of weight loss, dehydration, and metabolic acidosis in inoculated pigs, and LT complementation restored the virulence of this strain. These results support the hypothesis that LT is a more significant contributor than STb to the virulence of F4+ ETEC infections in young F4ac receptor-positive pigs less than 2 weeks old. However, in contrast to previous studies with gnotobiotic piglets, there was no evidence that the expression of LT enhanced the ability of the F4+ ETEC strain to colonize the small intestine

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

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