Characteristics of Salmonella isolated from an outbreak of equine salmonellosis in a veterinary teaching hospital

During an outbreak of equine salmonellosis in a veterinary teaching hospital 20 Salmonella isolates were cultured from sick horses (13 isolates) or from the hospital environment (7 isolates). Three serotypes were isolated from the environment including: S. give, S. newportand S. agona. The serotypes isolated from horses included: S. give, S. newport and S. anatum. Examination of antibiotic profiles, presence of plasmids, production of bacteriocins and hemagglutination of erythrocytes implied a common origin for the equine and environmental isolates.     

Isolation of picornavirus from feces and semen from an infertile bull.

Virus was isolated from semen and fecal samples from a bull with orchitis, testicular degeneration, aspermatogenesis, and loss of libido. Both isolates were classified as picornavirus, bovine enterovirus serotype I, on the basis of physical, chemical, and serologic characteristics. Veterinary practitioners that may suspect viral infection as a cause of bovine infertility should submit both semen and fecal samples for virus isolation and identification.     

An acute case of Pimelea elongata toxicity in cattle in western New South Wales

In May 2019, 96 cattle died from Pimelea toxicity in a period of 19 days after potential exposure, with the first deaths occurring within 5 days. After examining the circumstances, we suspect that several factors contributed to the deaths. These included that recently purchased stock and transported had access to flooded land containing Pimelea elongata. This weed species contains simplexin and 18 other compounds. Roots, flowers and seeds are significantly more toxic than the stem, branches and leaves. We suspect that thirsty and hungry stock consumed seed and roots from flooded pastures and consumed lethal doses of simplexin. Blood tests were not good indicators of the conditions. Management strategies are suggested.     

Effects of sodium nitroprusside after load reduction and/or atropine pre-treatment prior to dexmedetomidine administration on cardiovascular variables in dogs

The purpose of this study was to determine the cardiovascular effects of sodium nitroprusside (SNP)‐induced after load reduction in dogs administered dexmedetomidine (DEX). Using a randomized crossover design and allowing at least 2 weeks between treatments 12 adult hound dogs of either sex weighing 22 ± 1.7 SD kg were anesthetized by face mask administration of 2.9% ET sevoflurane to facilitate instrumentation prior to administration of treatment drugs. Dogs were intubated and instrumented to enable measurement of heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, mean pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), and cardiac output (CO). Systemic (SVR) and pulmonary vascular resistances were calculated. Following completion of instrumentation dogs were allowed to recover for 40 minutes. After collection of baseline data, dogs were administered one of four treatments at T–10 minutes prior to injection of DEX (500? g M^–2 IM): 1) saline (SAL); 2) atropine (ATR, 0.02 [n = 6] or 0.04 [n = 6] mg kg^–1 IM); 3) SAL + SNP (infused at 1–10 ?g kg^–1 minute^–1, IV as needed to maintain MAP between 90–110 mm Hg; or 4) ATR + SNP. Cardiovascular data were collected at T‐20 minutes prior to administration of DEX, T‐5 and at 5, 10, 20, 30, 40, and 60 minutes following DEX. Data were analyzed using anova for repeated measures with post hoc differences between means identified using Bonferroni's method (p < 0.05). Differences in ATR dose were not found to be significant and thus results for ATR dose groups were pooled. Administration of SAL (dexmedetomidine alone) was associated with decreases in HR and CO and increases in SAP, MAP, DAP, CVP, and SVR. Administration of ATR was associated with an increase in HR and CO compared with SAL. Administration of SNP was associated with an increase in HR and CO and a decrease in SVR, MAP and CVP compared with SAL. Administration of SNP + ATR was associated with effects similar to that of SNP or ATR alone and resulted in an additive increase in CO. We conclude that SNP‐induced afterload reduction with or without atropine is effective in mitigating DEX‐induced impairment of cardiovascular function.     

Characterizing avian Escherichia coli isolates with multiplex polymerase chain reaction

Colibacillosis caused by Escherichia coli infections account for significant morbidity and mortality in the poultry industry. Yet, despite the importance of colibacillosis, much about the virulence mechanisms employed by avian E. coli remains unknown. In recent years several genes have been linked to avian E. coli virulence, many of which reside on a large transmissible plasmid. In the present study, a multiplex polymerase chain reaction (PCR) protocol to detect the presence of four of these genes is described. Such a protocol may supplement current diagnostic schemes and provide a rapid means of characterizing the E. coli causing disease in poultry. The targets of this procedure included iss, the increased serum survival gene; tsh, the temperature sensitive hemagglutinin gene; cvi, the ColV immunity gene; and iucC, a gene of the aerobactin operon. Organisms, known for their possession or lack of these genes, were used as a source of the template DNA to develop the multiplex PCR protocol. Identity of the amplicons was confirmed by size, DNA:DNA hybridization with specific gene probes, and DNA sequencing. When the multiplex PCR protocol was used to characterize 10 E. coli isolates incriminated in avian colibacillosis and 10 from the feces of apparently healthy birds, nine of the isolates from apparently healthy birds contained no more than one gene, while the 10th contained all four. Also, eight of the isolates incriminated in colibacillosis contained three or more genes, while the remaining two contained two of the target genes. Interestingly, the isolates of sick birds containing only two of the targeted genes killed the least number of embryos,and the isolate of healthy birds that contained all the genes killed the most embryos amongthis group. These genes were not found among the non-E. coli isolates tested, demonstrating the procedure's specificity for E. coli. Overall, these results suggest that this protocol might be useful in characterization and study of avian E. coli.     

Comparison of the intravenous chicken challenge method with the embryo lethality assay for studies in avian colibacillosis

In previous studies, the embryo lethality assay (ELA) was able to discriminate between virulent and avirulent avian Escherichia coli isolates and to predict percent mortality of the embryos resulting from an isolate based on three traits. The abilities to resist host complement, presence of Colicin V activity, and presence of the increased serum survival gene cluster (iss), were used together in a logistic regression analysis to predict the percentage of embryo deaths resulting from each of 20 avian E. coli isolates used in the ELA. In the present study, the same 20 isolates are used in an intravenous chicken challenge model in an effort to determine whether the ELA could be used to replace chicken challenge studies. Correlations between the mortality and a combination of mortality and morbidity (the survivors at trial termination with lesions suggestive of colibacillosis) and the previous ELA results and with selected isolate traits were performed. Additionally, resulting body weights in surviving chickens were compared between groups. The highest positive correlations were observed between the ELA and the combined mortality/morbidity of the intravenous challenge (r = 0.861, P < 0.0001 for the first ELA challenge, and r = 0.830, P < 0.0001 for the second ELA challenge). The IV challenge combined mortality/morbidity results had the highest correlation coefficients with the presence of iss (r = 0.864, P < 0.0001) and the expression of ColV (r = 0.878, P < 0.0001). The presence of tsh was slightly correlated with mortality (r = 0.465, P = .0389) but demonstrated a higher correlation with the combined mortality and morbidity of the IV challenge (r = 0.558, P = 0.0106). Even though the ELA results in a higher number of nonspecific deaths, the two challenge methods exhibit similar results and a high correlation with each other. Interestingly, some of the isolates showed differences in their ability to cause mortality between the ELA and the IV challenge model. Furthermore, some isolates reflected significant differences in body weights of surviving birds at IV trial termination.     

The in vitro efficacy of a quaternary ammonia disinfectant and/or ethylenediaminetetraacetic acid-tris against commercial broiler hatchery isolates of Pseudomonas aeruginosa

Studies have indicated variations in the degree of efficacy of certain commercial disinfectants used in poultry production facilities. We used an adequate method of in vitro testing to compare the efficacy of disinfectants while testing them in conditions similar to those of the poultry facilities. BioSentry 904, ethylenediaminetetracetic acid (EDTA)-Tris, and a combination of the two were tested by this method against five field isolates of Pseudomonas aeruginosa at 10(3), 10(6), and 10(9) colony-forming units (CFU)/ml. At the 10(9) CFU/ml concentration, most compounds failed to achieve a total kill with a contact time of 15 min. When tested at bacterial concentrations of 10(3) CFU/ml, the combination of EDTA-Tris mixed at a 1:1 ratio with BioSentry 904 killed the bacteria upon initial contact (< or = 0.05 min). This disinfectant mixture exhibited antagonistic, indifferent, or synergetic effects when exposed to different bacterial isolates at a concentration of 10(6) CFU/ml.     

Immunolocalization of Aquaporins 1 and 9 in the Ram Efferent Ducts and Epididymis

Aquaporins (AQPs) are essential membrane protein channels for the transport of water across membranes. Fluid movement in the epididymis is important for modulation of the luminal environment, in which sperm mature and reside. This study was designed to understand the morphology and localization of AQPs in ram efferent ducts (ED) and epididymis. For this purpose, the epididymis of seven animals were removed for histologic and immunohistochemical analyses. AQP1 immunoreactivity was observed in the apex of the ED, and AQP9 was found adjacent to the nuclei of the epithelial cells of the ED. The epithelial lining of ram epididymis is pseudostratified columnar and presents principal, basal, apical and narrow cells. In the initial segment (IS), a moderate reaction for AQP1 was observed in the apical cytoplasm of epithelial cells. An intense reactivity for AQP1 was noted over the microvilli of principal cells and in spermatozoa in the caput. In the corpus and cauda, AQP1 was noted only over the endothelial cells of vascular channels located in intertubular spaces. A weak‐to‐moderate reaction for AQP9 was observed in the nuclei of epithelial cells in the IS, caput and corpus of the epididymis. In the cauda, an intense reaction to AQP9 was observed in the epithelial border. In the IS, caput and corpus, the reactivity for AQP9 differed from those observed in domestic animals. The cauda showed a pattern similar to that previously described. These results indicate that AQPs 1 and 9 have reversed locations and roles in rams, suggesting activity variations related with fluid and solute absorption throughout the epididymis.     

The convergence of synthetic organic and polymer chemistries

Several recent conceptual advances, which take advantage of the design criteria and practical techniques of molecular-level control in organic chemistry, allow preparation of well-defined polymers and nanostructured materials. Two trends are clear: the realization that synthesis of complex macromolecules poses major challenges and opportunities and the expectation that such materials will exhibit distinctive properties and functions. Polymer synthesis methods now being developed will yield well-defined synthetic macromolecules that are capable of mimicking many of the features of proteins (for example, three-dimensional folded structure) and other natural materials. These macromolecules have far-reaching potential for the study of molecular-level behavior at interfaces, in thin films, and in solution, while also enabling the development of encapsulation, drug-delivery, and nanoscale-patterning technologies.