Degradation kinetics and mechanism of antibiotic ceftiofur in recycled water derived from a beef farm

Ceftiofur is a third-generation cephalosporin antibiotic that has been widely used to treat bacterial infections in concentrated animal feeding operations (CAFOs). Land application of CAFO waste may lead to the loading of ceftiofur residues and its metabolites to the environment. To understand the potential contamination of the antibiotic in the environment, the degradation kinetics and mechanisms of ceftiofur in solutions blended with and without the recycled water derived from a beef farm were investigated. The transformation of ceftiofur in aqueous solutions in the presence of the CAFO recycled water was the combined process of hydrolysis and biodegradation. The total degradation rates of ceftiofur at 15 °C, 25 °C, 35 °C, and 45 °C varied from 0.4-2.8×10(-3), 1.4-4.4×10(-3), 6.3-11×10(-3), and 11-17×10(-3) h(-1), respectively, in aqueous solutions blended with 1 to 5% CAFO recycled water. Hydrolysis of ceftiofur increased with incubation temperature from 15 to 45 °C. The biodegradation rates of ceftiofur were also temperature-dependent and increased with the application amounts of the recycled CAFO water. Cef-aldehyde and desfuroylceftiofur (DFC) were identified as the main biodegradation and hydrolysis products, respectively. This result suggests that the primary biodegradation mechanism of ceftiofur was the cleavage of the β-lactam ring, while hydrolytic cleavage occurred at the thioester bond. Unlike DFC and ceftiofur, cef-aldehyde does not contain a β-lactam ring and has less antimicrobial activity, indicating that the biodegradation of ceftiofur in animal wastewater may mitigate the potentially adverse impact of the antibiotic to the environment.     

Endoscopically assisted nasojejunal feeding tube placement: technique and results in five dogs

Interest in noninvasive feeding tube placement in companion animals led to the adaption of a human technique utilizing endoscopy to place nasojejunal feeding tubes. Data from medical records in which nasojejunal feeding tubes were attempted were reviewed. Feeding tubes were attempted and successfully placed in five dogs within a median of 35 min. Feeding tubes remained in place for approximately 7 days. Complications included facial irritation (5/5), sneezing (5/5), fractured facial sutures (4/5), vomiting (3/5), diarrhea (3/5), crimping of feeding tube (3/5), regurgitation (1/5), epistaxis (1/5), clogging of the feeding tube (2/5), and oral migration with premature removal of the feeding tube (1/5). The deployment technique used in this study was found to be cumbersome. Despite minor complications, endoscopy can be used to rapidly and accurately place nasoenteric feeding devices.     

Estimated within-herd prevalence (WHP) of Mycobacterium avium subsp. paratuberculosis in a sample of Minnesota dairy herds using bacterial culture of pooled fecal samples

The objective of this study was to describe the estimated within-herd prevalence (WHP) of Mycobacterium avium subsp. paratuberculosis (Map) in a sample of infected dairy herds in Minnesota (N = 66) using test results from bacterial culture of pooled fecal samples. Fecal samples were collected from up to 100 cows in each herd and were tested using bacterial culture in pools of 5 cows based on age order. The mean herd size was 222 (44 to 1500) milking cows; the cows were predominantly Holstein. Using a frequentist approach, the within-herd mean individual fecal prevalence was 10% [95% confidence interval (CI) = 4% to 16%] assuming 70% test sensitivity and 99.5% test specificity. Using Bayesian methods, the estimated true within-herd individual cow prevalence was 14% (95% CI = 7% to 27%). Within-herd prevalence was higher in larger dairy herds than in herds with fewer cows. As Map is the causative agent of Johne's disease (JD), the results of this study could contribute to the success of a nationwide control program for this disease.     

"养鸡生产中沙门氏菌病的预防与控制策略"专栏(五)控制家禽产品的沙门氏杆菌感染

家禽沙门氏菌感染如何开始的以及应采取何种措施进行预防往往难以确定.肉鸡可能会通过垂直传播(从父母代鸡群)与水平传播(环境)两种途径感染沙门氏菌.本文将阐述沙门氏菌如何感染家禽,同时介绍预防与控制沙门氏菌的有效措施.     

Cardiac tamponade in largemouth bass (Micropterus salmoides)

A public aquarium with a 4-mo history of occasional fish mortalities submitted for necropsy an adult female largemouth bass (Micropterus salmoides) that died unexpectedly. Gross necropsy revealed that the pericardial cavity was markedly distended with partially coagulated blood. Examination of the heart revealed multiple nodular masses in the area of the atrium and two small perforations on the surface of one of the nodular masses. Histopathologic exam of the atrium revealed severe fibrinonecrotic endocarditis and transmural myocarditis with intralesional bacteria. A pure culture of Edwardsiella tarda was obtained from culture of posterior kidney and spleen. An area of stagnant water that may serve as the source of E. tarda was identified, and steps to rectify this problem were taken. Low-level supersaturation was also a significant stressor; the source of the supersaturation was not identified. To our knowledge, this is the first report of cardiac tamponade in a largemouth bass.     

Mycobacterium kansashi infection in a bontebok (Damaliscus pygaragus dorcas) herd: diagnostic challenges in differentiating from the Mycobacterium tuberculosis complex

Two adult female bontebok (Damaliscus pygarus dorcas) were euthanized because of signs of pneumonia and weakness (case 1), and a nonresponsive lameness with draining fistula (case 2). Necropsy findings were similar in both cases and consisted of disseminated granulomatous lesions in the liver, kidneys, spleen, lungs, pleural surfaces, and multiple lymph nodes. Mycobacterium kansasii was isolated from both cases after multiple attempts on a variety of samples by two laboratories. The remaining four animals in the herd were tested for antibody responses using the Chembio ElephantTB STAT-PAK, DPP VetTB kits, and multi-antigen print immunoassay (MAPIA), for immune reaction using the intradermal tuberculin test, and by tracheal wash cultures, and thoracic radiographs. Banked serum samples collected in 2005 and obtained from the original institution, revealed 1/9 (11.11%) seropositive animals using the three immunoassays. Retesting the current herd in 2008 showed 2/6 (33.33%) seropositive animals by the three tests, with MAPIA demonstrating antibody reactivity to MPB83 and MPB70 proteins. Inconsistent intradermal tuberculin test results, cross-reactivity in serologic assays designed for tuberculosis detection, difficulty in obtaining definitive identification by culture, and inability to identify a source of infection created challenges in distinguishing the atypical mycobacteriosis due to M. kansasii from the initially suspected tuberculous infection in this herd. Owing to regulatory considerations, differences in host-to-host transmission, and source of infection between Mycobacterium tuberculosis complex and nontuberculous mycobacteria, correct diagnosis is crucial for management of these diseases in wildlife species.     

Minimum anesthetic concentration and cardiovascular dose-response relationship of isoflurane in cinereous vultures (Aegypius monachus)

This study aimed to determine the minimum anesthetic concentration (MAC) and dose-related cardiovascular effects of isoflurane during controlled ventilation in cinereous vultures (Aegypius monachus). The MAC was determined for 10 cinereous vultures as the midpoint between the end-tidal isoflurane concentration that allows gross purposeful movement and that which prevents the movement in response to clamping a pedal digit. Immediately after the MAC was determined, the cardiovascular effects of isoflurane at 1.0, 1.5, and 2.0 times the MAC were investigated in seven of the 10 birds. The MAC of isoflurane for 10 cinereous vultures during controlled ventilation was 1.06 +/- 0.07% (mean +/- SD). When the isoflurane concentration was increased to 1.5 and 2.0 times the MAC, there was significant dose-dependent decrease in the arterial blood pressure. However, the heart rate did not change over a range of 1.0 to 2.0 times the MAC.     

Intra-articular drug delivery: the challenge to extend drug residence time within the joint

The rationale behind developing sustained release microsphere formulations of non-steroidal anti-inflammatory drugs (NSAIDs) administered via the intra-articular (IA) route is to minimise the systemic bioavailability and attendant side-effects associated with oral drug administration. Overall dose is reduced whilst therapeutic benefit within the joint is maintained. The potential benefits of IA therapy for osteoarthritis (OA) are not achieved using currently available medications and delivery vehicles due to the rapid clearance of therapeutic substances from the synovial space. There is a need for sustained release delivery systems if the potential of IA drug administration is to be realised. Rationally designed microspheres taken up by synovial macrophages offer a strategy to sustain drug delivery within the joint, and to deliver NSAIDs directly to pivotal inflammatory cells. The efficacy of microsphere candidates may be evaluated in large animal models of OA. The principles of IA microsphere drug delivery may also be applicable to other classes of drugs.     

Cervical dermoid sinus in a cat: case presentation and review of the literature

A 6-month-old female spayed domestic shorthair cat was presented for evaluation of a focal subcutaneous swelling on the dorsal neck at the level of atlas. The magnetic resonance imaging and surgical treatment of a dermoid sinus associated with the cervical vertebrae is described. To the authors' knowledge, a dermoid sinus in this location has not been described previously in the cat. The prognosis following surgical resection appears favorable.