Clostridioides difficile on Ohio swine farms (2015): A comparison of swine and human environments and assessment of on‐farm risk factors

Swine are known reservoirs for Clostridioides difficile, formerly known as Clostridium difficile, and transmission from swine to human farm workers is strongly suggested by previous studies. This cross‐sectional study evaluated the potential role of farm environmental surfaces, including those in worker breakrooms and swine housing areas, in the possible transmission of C. difficile from swine to farm workers. Environmental surfaces and piglet faeces at 13 Ohio swine farms were sampled in 2015. Typical culturing techniques were performed to isolate C. difficile from samples, and amplification of toxin genes (tcdA, tcdB and cdtB) and PCR‐ribotyping were used to genetically characterize recovered isolates. In addition, sequencing of toxin regulatory gene, tcdC, was done to identify the length of identified deletions in some isolates. A survey collected farm‐level management risk factor information. Clostridioides difficile was recovered from all farms, with 42% (188/445) of samples testing positive for C. difficile. Samples collected from all on‐farm locations recovered C. difficile, including farrowing rooms (60%, 107/178), breakrooms (50%, 69/138) and nursery rooms (9%, 12/129). Three ribotypes recovered from both swine and human environments (078, 412 and 005) have been previously implicated in human disease. Samples taken from farrowing rooms and breakrooms were found to have greater odds of C. difficile recovery than those taken from nursery rooms (OR = 40.5, OR = 35.6, p < .001 respectively). Farms that weaned ≥23,500 pigs per year had lower odds of C. difficile recovery as compared to farms that weaned fewer pigs (OR = 0.4, p = .01) and weekly or more frequent cleaning of breakroom counters was associated with higher odds of C. difficile recovery (OR = 11.7, p < .001). This study provides important insights into the presence and characterization of C. difficile found in human environments on swine farms and highlights how these areas may be involved in transmission of C. difficile to swine farm workers and throughout the facility.     

The isoflurane-sparing and clinical effects of a constant rate infusion of remifentanil in dogs

OBJECTIVE: To evaluate the isoflurane-sparing and clinical effects of two constant rate infusions of remifentanil in healthy dogs undergoing orthopaedic surgery. STUDY DESIGN: Prospective, randomized clinical study. ANIMALS: Forty-one American Society of Anesthesiologists I-II client-owned dogs (age, 7 months-9 years; body mass 11-59 kg). METHODS: Dogs were randomly assigned to one of three groups and received either: intramuscular (IM) meperidine 2 mg kg(-1) every 2 hours throughout surgery (control group (C); n = 13); remifentanil infused intravenously (IV) at 0.1 microg kg(-1) minute(-1) (low remifentanil group (L); n = 14) or remifentanil infused at 0.25 microg kg(-1) minute(-1) IV (high remifentanil group (H); n = 14). Anaesthesia was induced with thiopental administered to effect and maintained using isoflurane in 100% oxygen. During controlled ventilation when the end-tidal CO(2) was maintained between 4.65 and 5.98 kPa [35-45 mmHg], the end-tidal isoflurane concentration (e'iso%), mean arterial blood pressure (MAP) and heart rate (HR) were measured every 5 minutes. Bradycardia (HR < 40 minute(-1) lasting >5 minutes) was corrected with 0.01 mg kg(-1) IV glycopyrrolate. Data were analysed using the Kruskal-Wallis test with a post-hoc Mann-Whitney U-test and Bonferroni correction. Statistical significance was accepted at < or = 0.05. Data are expressed as mean +/- standard deviation. RESULTS: The e'iso% was reduced in a dose-dependent manner by remifentanil. In C, e'iso% was 1.28 +/-0.13 and was significantly different from L (0.78 +/- 0.17, p < 0.001) and H (0.65 +/- 0.16, p < 0.001). HR was significantly different between groups (p < 0.001). There were no significant differences in MAP between groups. Glycopyrrolate was required in two, three and six dogs in the C, L and H groups respectively. CONCLUSIONS: Remifentanil infusion reduced the isoflurane concentration required for surgical anaesthesia during orthopaedic surgery. CLINICAL RELEVANCE: Remifentanil infusions may be a useful additive to isoflurane anaesthesia in healthy dogs.     

Relationships between genetic distance measured by RAPD-PCR and heterosis in inbred lines of white clover (Trifolium repens L.)

The RAPD-PCR technique has been used to generate DNA amplification profiles from a set of advanced generation inbred lines of white clover ( Trifolium repens L.). The genetic distances between lines have been estimated and have been compared with the extent of positive heterosis for dry matter yield in hybrid crosses. The analysis clearly separated the four major groups (H, J, R and S), with little within group variation. Heterosis, previously shown to be positively correlated with the extent of phenotypic variation between parental lines, was greatest between lines from groups showing the least genetic distance. The lack of correlation between heterosis and genetic divergence is discussed in the context of results from other systems. Additionally, the data allow a comparison of the extent of phenotypic variation for a trait under selective pressure with the degree of variation at the DNA level detected with the RAPD technique. This revised version was published online in July 2006 with corrections to the Cover Date.     

Invasive Chinese pond mussel Sinanodonta woodiana threatens native mussel reproduction by inducing cross‐resistance of host fish

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Conservation implications of isotopic variation in nails and blood with wetland quality in three species of Australian freshwater turtle

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Habitat use of a coastal delphinid population investigated using passive acoustic monitoring

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Difficulties associated with modeling growth in the Atlantic angel shark (Squatina dumeril)

Several methods were used in an attempt to develop an age and growth model for the Atlantic angel shark (Squatina dumeril). Band counts from vertebral sections, which were fit to the traditional von Bertalanffy growth equation, the Gompertz growth equation, and the two-parameter von Bertalanffy growth equation, did not produce realistic parameter estimates. Additionally, a length-based Bayesian model was applied to fishery-independent length–frequency data, and a full Bayesian model was fitted to length-at-age data to estimate parameters for von Bertalanffy growth equation. Both the length-based and full Bayesian models failed to converge; the length–frequency data showed high bimodality unrelated to season, year, or other factors, and band counts were not predictable by length. Vertebral band counts were not valid for ageing Atlantic angel sharks, and length-based methods, which require normally distributed length–frequencies, were not appropriate for this data set. This study represents the first attempt at modeling age and growth for this species and provides research guidelines for future research initiatives.