Characterization of Mannheimia haemolytica isolated from feedlot cattle that were healthy or treated for bovine respiratory disease     

Cassidy L. Klima  Trevor W. Alexander  Steve Hendrick  Tim A. McAllister 《Canadian journal of veterinary research》2014,78(1):38-45

Mannheimia haemolytica is the principal bacterial pathogen associated with bovine respiratory disease (BRD). As an opportunistic pathogen, M. haemolytica is also frequently isolated from the respiratory tract of healthy cattle. This study examined the characteristics of M. haemolytica collected using deep nasal swabs from healthy cattle (n = 49) and cattle diagnosed with BRD (n = 41). Isolates were analyzed by pulsed-field gel electrophoresis (PFGE), serotyped, and tested for antimicrobial susceptibility. Polymerase chain reaction (PCR) was used to screen isolates for virulence [leukotoxin C (lktC), putative adhesin (ahs), outer-membrane lipoprotein (gs60), O-sialoglycoprotease (gcp), transferring-binding protein B (tbpB) and UDP-N-acetyl-D-glucosamine-2-epimerase (nmaA)] and antimicrobial resistance [tet(H), bla_ROB-1, erm(X), erm(42), msr(E)-mph(E) and aphA-1] genes. Isolates were genetically diverse but in three instances, M. haemolytica with the same pulsotype, resistance phenotype, and genotype were collected from cattle with BRD. This occurred once between cattle located in two different feedlots, once between cattle in the same feedlot, but in different pens, and once among cattle from the same feedlot in the same pen. Isolates from healthy cattle were primarily serotype 2 (75.5%) while those from individuals with BRD were serotype 1 (70.7%) or 6 (19.5%). Resistance to at least one antibiotic occurred more frequently (P < 0.001) in M. haemolytica collected from cattle with BRD (37%) compared with those that were healthy (2%). Overall, tetracycline resistance (18%) was the most prevalent resistant phenotype. All tetracycline-resistant M. haemolytica encoded tet(H). Ampicillin resistance (6%) and neomycin resistance (15%) were detected and corresponded to the presence of the bla_ROB-1 and aphA-1 genes, respectively. Tilmicosin resistance (6%) was also detected, but the resistance genes responsible were not identified. The virulence genes lktC, ahs, gs60, and gcp were present in all isolates examined, while tbpB and nmaA were only detected in serotype 1 and serotype 6 isolates indicating they may be potential targets for serotype-specific identification or vaccine development. These results provide the first reported evidence of transmission and spread of antimicrobial-resistant M. haemolytica that have contributed to bovine respiratory disease in western Canadian feedlots.  相似文献   

Immunity,safety and protection of an Adenovirus 5 prime - Modified Vaccinia virus Ankara boost subunit vaccine against Mycobacterium avium subspecies paratuberculosis infection in calves     

Tim J Bull  Christina Vrettou  Richard Linedale  Catherine McGuinnes  Sam Strain  Jim McNair  Sarah C Gilbert  Jayne C Hope 《Veterinary research》2014,45(1)

Vaccination is the most cost effective control measure for Johne’s disease caused by Mycobacterium avium subspecies paratuberculosis (MAP) but currently available whole cell killed formulations have limited efficacy and are incompatible with the diagnosis of bovine tuberculosis by tuberculin skin test. We have evaluated the utility of a viral delivery regimen of non-replicative human Adenovirus 5 and Modified Vaccinia virus Ankara recombinant for early entry MAP specific antigens (HAV) to show protection against challenge in a calf model and extensively screened for differential immunological markers associated with protection. We have shown that HAV vaccination was well tolerated, could be detected using a differentiation of infected and vaccinated animals (DIVA) test, showed no cross-reactivity with tuberculin and provided a degree of protection against challenge evidenced by a lack of faecal shedding in vaccinated animals that persisted throughout the 7 month infection period. Calves given HAV vaccination had significant priming and boosting of MAP derived antigen (PPD-J) specific CD4⁺, CD8⁺ IFN-γ producing T-cell populations and, upon challenge, developed early specific Th17 related immune responses, enhanced IFN-γ responses and retained a high MAP killing capacity in blood. During later phases post MAP challenge, PPD-J antigen specific IFN-γ and Th17 responses in HAV vaccinated animals corresponded with improvements in peripheral bacteraemia. By contrast a lack of IFN-γ, induction of FoxP3+ T cells and increased IL-1β and IL-10 secretion were indicative of progressive infection in Sham vaccinated animals. We conclude that HAV vaccination shows excellent promise as a new tool for improving control of MAP infection in cattle.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-014-0112-9) contains supplementary material, which is available to authorized users.  相似文献   

建在蒙古国橱柜工厂的挑战     

Tim Langerock 《国际木业》2014,(8)

大多数人都知道蒙古的首都是乌兰巴托,蒙古国有317万人口,其中170万人都是生活在乌兰巴托市.多数人从历史课上知道,这里除了乌兰巴托外只有另外三个值得一提的城市.尽管有乌兰巴托这样一个繁荣的国际都市,以及快速增长的GDP,蒙古却一直都是一个被游牧文化深深地打上烙印的国家.出于几点不同的原因,那么在这里规划生产橱柜的工厂是一个挑战.  相似文献   

Sedative and antinociceptive effects of dexmedetomidine and buprenorphine after oral transmucosal or intramuscular administration in cats     

Nathalie Porters  Tim Bosmans  Mariëlla Debille  Hilde de Rooster  Luc Duchateau  Ingeborgh Polis 《Veterinary anaesthesia and analgesia》2014,41(1):90-96

ObjectiveTo compare sedation and antinociception after oral transmucosal (OTM) and intramuscular (IM) administration of a dexmedetomidine-buprenorphine combination in healthy adult cats.Study designRandomized, ‘blinded’ crossover study, with 1 month washout between treatments.AnimalsSix healthy neutered female cats, weighing 5.3–7.5 kg.MethodsA combination of dexmedetomidine (40 μg kg^?1) and buprenorphine (20 μg kg^?1) was administered by either the OTM (buccal cavity) or IM (quadriceps muscle) route. Sedation was measured using a numerical rating scale, at baseline and at various time points until 6 hours after treatment. At the same time points, analgesia was scored using a dynamic and interactive visual analogue scale, based on the response to an ear pinch, and by the cat’s response to a mechanical stimulus exerted by a pressure rate onset device. Physiological and adverse effects were recorded, and oral pH measured. Signed rank tests were performed, with significance set at p < 0.05. Data are presented as median and range.ResultsThere were no differences in sedation or antinociception scores between OTM and IM dosing at any of the time points. Nociceptive thresholds increased after both treatments but without significant difference between groups. Buccal pH remained between 8 and 8.5. Salivation was noted after OTM administration (n = 2) and vomiting after both OTM (n = 4), and IM (n = 3) dosing.Conclusions and clinical relevanceIn healthy adult cats, OTM administration of dexmedetomidine and buprenorphine resulted in comparable levels of sedation and antinociception to IM dosing. The OTM administration may offer an alternative route to administer this sedative-analgesic combination in cats.  相似文献   

Limnology in developing countries,vol. 3, edited by R. G. Wetzel and B. Gopal. International Scientific Publications Publishers,New Delhi,India, 2001, vii+189pp.     

Tim Moulton 《水产资源保护:海洋与淡水生态系统》2003,13(4):370-371

  相似文献   

Autopsy your dead…and living: a proposal for fisheries science, fisheries management and fisheries     

Tim D. Smith  & Jason S. Link 《Fish and Fisheries》2005,6(1):73-87

  相似文献   

Soil aeration and redox potential as function of pore connectivity unravelled by X-ray microtomography imaging     

Kristof Dorau  Daniel Uteau  Maren Pia Hövels  Stephan Peth  Tim Mansfeldt 《European Journal of Soil Science》2022,73(1):e13165

  相似文献   

Clinicopathologic features of suspected brevetoxicosis in double-crested cormorants (Phalacrocorax auritus) along the Florida Gulf Coast.     

Christine Kreuder  Jonna A K Mazet  Gregory D Bossart  Tim E Carpenter  Marcel Holyoak  Marc S Elie  Scott D Wright 《Journal of zoo and wildlife medicine》2002,33(1):8-15

Outbreaks of morbidity and mortality in double-crested cormorants (Phalacrocorax auritus) along Florida's Gulf Coast have occurred sporadically for at least 30 yr. During these outbreaks, the Clinic for the Rehabilitation of Wildlife, located on Sanibel Island in Florida, has admitted a substantial number of cormorants with consistent presentation of primarily neurologic clinical signs. In order to investigate the association of these outbreaks in cormorants with exposure to brevetoxin, we compared the timing of admittance of cormorants with outbreak-specific clinical signs to blooms of the brevetoxin-producing marine algae, Karenia brevis (formerly Gymnodinium breve), around Sanibel Island from 1995 through 1999. The clinic admitted 360 out of 613 cormorants with the common clinical sign of severe cerebellar ataxia in six outbreaks occurring during this period. The ataxia was characterized by a broad-based stance, truncal incoordination, hypermetric gait, and intention tremors of the head. The histopathologic findings in 10 cormorants euthanized in 1997 were mild and nonspecific. An immunohistochemical staining technique for the detection of brevetoxin in cormorants documented the uptake of brevetoxin in tissues from four cormorants admitted during an outbreak in 1997, but a modified technique used on samples from 11 cormorants admitted during a K. brevis bloom in 2000 produced indeterminate results. Admittance of cormorants with outbreak-specific clinical signs was positively correlated (P < 0.05) with concurrent concentrations of K. brevis in local water. The cross-correlation coefficient was also significant when increased K. brevis levels preceded cormorant admittances by 2, 4, 6, and 8 wk. This delay in time between K. brevis blooms and cormorant admittance and our clinical finding of neurologic abnormalities in cormorants without overt histopathologic features suggest an association between K. brevis blooms and local cormorant morbidity.  相似文献   

The Frankenstein Syndrome: Ethical and Social Issues in the Genetic Engineering of Animals          下载免费PDF全文

Tim Blackwell 《The Canadian veterinary journal. La revue veterinaire canadienne》1996,37(12):757

  相似文献   

Pulse oximetry and end tidal carbon dioxide monitoring.     

Tim B Hackett 《Veterinary Clinics of North America: Small Animal Practice》2002,32(5):1021-1029

Noninvasive monitoring of cardiopulmonary function through pulse oximetry and capnography provides immediate and important information for the clinician. These monitors are not a replacement for vigilant attention to the patient, however; they should be used in conjunction with arterial blood gas analysis and serial physical examinations to ensure that the continuous readings are accurate and make clinical sense.  相似文献