Biofilm bacteria: formation and comparative susceptibility to antibiotics

The Calgary Biofilm Device (CBD) was used to form bacterial biofilms of selected veterinary gram-negative and gram-positive pathogenic bacteria from cattle, sheep, pigs, chicken, and turkeys. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of ampicillin, ceftiofur, cloxacillin, oxytetracycline, penicillin G, streptomycin, tetracycline, enrofloxacin, erythromycin, gentamicin, tilmicosin, and trimethoprim-sulfadoxine for gram-positive and -negative bacteria were determined. Bacterial biofilms were readily formed on the CBD under selected conditions. The biofilms consisted of microcolonies encased in extracellular polysaccharide material. Biofilms composed of Arcanobacterium (Actinomyces) pyogenes, Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, Corynebacterium renale, or Corynebacterium pseudotuberculosis were not killed by the antibiotics tested but as planktonic bacteria they were sensitive at low concentrations. Biofilm and planktonic Streptococcus dysgalactiae and Streptococcus suis were sensitive to penicillin, ceftiofur, cloxacillin, ampicillin, and oxytetracycline. Planktonic Escherichia coli were sensitive to enrofloxacin, gentamicin, oxytetracycline and trimethoprim/ sulfadoxine. Enrofloxacin and gentamicin were the most effective antibiotics against E. coli growing as a biofilm. Salmonella spp. and Pseudomonas aeruginosa isolates growing as planktonic populations were sensitive to enrofloxacin, gentamicin, ampicillin, oxytetracycline, and trimethoprim/sulfadoxine, but as a biofilm, these bacteria were only sensitive to enrofloxacin. Planktonic and biofilm Pasteurella multocida and Mannheimia haemolytica had similar antibiotic sensitivity profiles and were sensitive to most of the antibiotics tested. The CBD provides a valuable new technology that can be used to select antibiotics that are able to kill bacteria growing as biofilms.     

Herbicide penetration across isolated and intact leaf cuticles

Penetration of four herbicides (atrazine, diclofop-methyl, dinoseb and glyphosate-mono(isopropylammonium) salt) was followed through isolated pear leaf cuticles into agar and across intact cuticles of Argenteum (ARG) mutant pea leaves from monosized droplets (300 μ diam.) during 48 h following application. Penetration into pea leaves ranged from low for glyphosatemono(isopropylammonium) (5% of amount applied) and atrazine (14%) to rapid for dinoseb (91%) and diclofop-methyl (82%). A major proportion (90%) of the dinoseb retained in the tissues underlying the site of droplet application migrated across the cuticle and the epidermal layer of cells. In contrast, only a small proportion (13%) of the dinoseb entering the leaf was transported to the tissues surrounding the treatment zone. Corresponding values for diclofop-methyl were 61% and 4% respectively. Initially, dinoseb also penetrated rapidly through isolated pear leaf cuticles, 36% of the applied dose being recovered in an agar receiver disc 4 h after treatment, but subsequent uptake was slower. Penetration of glyphosate-mono(isopropylammonium) also decreased after 4 h whereas atrazine and diclofop-methyl diffused steadily through isolated cuticles up to 216 h after treatment. The incorporation of ‘Tween 20’ or ‘Agral 90’ (1 g litre^?1) into the formulation reduced the penetration of glyphosate-mono(isopropylammonium) through isolated pear leaf cuticles.     

Fin erosion on rainbow trout on commercial trout farms in the United Kingdom

Fish weighing less than 30 g and more than 100 g were sampled from 38 rearing units on 10 commercial farms growing rainbow trout for the table market. A fin index was calculated for each of the eight rayed fins on 949 trout by dividing their length by the standard length of the fish. There was a large range in the indices of all eight fins. The fin indices of the small and large fish were compared, controlling for farm effect. With the exception of the dorsal fin, all the indices were larger for the small fish than for the large fish, but the magnitude of the difference was greater for some fins than others. In comparison with the fins of wild fish, the pectoral and dorsal fins appeared to be most eroded and the damage to these fins was evident even in the small fish. The erosion of the caudal, anal and ventral (or pelvic) fins was more prominent in the larger fish. Variations in the fin indices of the caudal, anal and ventral fins suggested that there was little variation between rearing units on the same farm, but that there was significant variation between individual fish in the same rearing units, and between fish on different farms.     

Finishing plant diet supplemented with microalgae meal increases the docosahexaenoic acid content in Colossoma macropomum flesh

The need for a sustainable aquaculture is increasing the use of plant ingredients in replacement to fishmeal and fish oil in diets for tambaqui Colossoma macropomum, which is leading to not detectable levels of docosahexaenoic acid (DHA) in its flesh. We evaluated the effect of a finishing plant diet supplemented with 5% of microalgae meal from Schizochytrium sp. (MD) on tambaqui growth, on proximal composition and fatty acid content of its flesh, comparing it to a non‐supplemented diet. One hundred and sixty‐two fish (489.67 g) were distributed into six tanks (2,000 L) and fed the experimental diets for a 90‐day period. Three fish per tank were euthanized for analyses every 15 days. The MD did not affect the growth and proximal composition of fish flesh. The MD increased the DHA content (from 14.81 to 38.60 mg/g of lipids) and the n‐3:n‐6 ratio (from 0.16 to 0.51) in the flesh of fish, beginning on the 15th day and reaching the highest DHA content on the 71st day (39.81 mg/g of lipids). We recommend C. macropomum to be fed with a finishing diet supplemented with microalgae meal for 71 days before slaughter to improve the DHA content and n‐3:n‐6 ratio in the flesh.     

Laparoscopic-assisted colopexy and sterilization in male dogs: short-term results and physiologic consequences

Objective: To describe laparoscopic‐assisted colopexy and sterilization, and evaluate outcome and effects in healthy male dogs. Study Design: Experimental study. Animals: Male Beagle dogs (n=7). Methods: A laparoscopic‐assisted, extracorporeally sutured colopexy, and sterilization by ligation and section of the testicular vessels and ductus deferens were evaluated 11 weeks after surgery. Ex vivo tensile tests were performed on the colopexy sites and loss of testicular function was assessed by monitoring serum testosterone, and by ultrasonographic and histologic examinations of the testes. Systemic inflammation and potential iatrogenic colonic functional disorders were investigated by monitoring serum C‐reactive protein (CRP) in the perioperative period and from a sulfapyridine (SP) kinetic profile obtained before and 10 weeks after surgery. Results: No intraoperative complications were recorded and clinical outcome was considered fair in all dogs. A mean tensile force of 42 N was required to disrupt colopexies. No relevant postoperative increase in CRP concentrations or changes in SP kinetics were observed. Testicular function was lost. Conclusions: Laparoscopic‐assisted colopexy achieved adhesion of the colon to the abdominal wall and testicular endocrine function and spermatogenesis were eliminated by laparoscopic castration.     

Systemic lidocaine infusion as an analgesic for intraocular surgery in dogs: a pilot study

Objective To determine if systemic administration of lidocaine during intraocular surgery reduces post-operative ocular pain. Study design Randomized, masked, controlled experimental trial. Animals Twelve dogs weighing 15.5 ± 1.7 kg (mean ± SD) and aged 2.5 ± 0.6 years. Methods All dogs underwent a baseline ophthalmic examination and subjective pain score. Anesthesia consisted of acepromazine (0.1 mg kg⁻¹, IM), propofol (4–6 mg kg⁻¹, IV), and isoflurane in oxygen. There were three groups each receiving a bolus followed by an infusion (n = 4): saline (0.3 mL kg⁻¹ IV + 0.2 mL kg⁻¹hour⁻¹ IV); morphine (0.15 mg kg⁻¹ IV + 0.1 mg kg⁻¹hour⁻¹ IV); and lidocaine (1.0 mg kg⁻¹ IV + 0.025 mg kg⁻¹minute⁻¹ IV). All treatments began 15 minutes prior to starting of phacoemulsification and lens removal from the right eye. Pain scores were recorded at 0.5, 1, 2, 3, 4, 6, 8, 16, and 24 hours after t = 0 (extubation). Rescue morphine was administered (1.0 mg kg⁻¹ IM) if the subjective pain score ≥9 (maximum = 24), and the dog was excluded from further data analysis. Differences in pain scores and time-to-treatment failure (TTF) were analyzed using the Wilcoxon's rank sum test. Differences in incidence of treatment failure were analyzed using Fisher's exact test. Physiologic data were analyzed using repeated measures anova . Significance was defined as P < 0.05. Results Incidence of treatment failure was 100% in saline-treated dogs and 50% in morphine- or lidocaine-treated dogs. There was no difference in intraocular pressure, aqueous flare, cell count (or protein) between groups in the operated eye at any time following extubation. Conclusion and clinical relevance This pilot study suggests that intraoperative lidocaine may provide analgesic benefits similar to morphine for intraocular surgery in dogs, but more definitive research is needed. This model appears to be appropriate for pain assessment studies as the negative control group demonstrated 100% failure rate.     

The Role of Traditional Irrigation Canals in a Long Term Environmental Perspective A Case Study in Southern France： The Durance Basin

The agricultural sector is often considered to be the largest water consumer and the policy aimed at saving irrigation water exists across Europe. The flip-side of such policy, however, is the disappearance of traditional irrigation canals since farmers are encouraged to turn to drip irrigation and overhead irrigation gradually. Given this, we would like to argue that traditional irrigation canals need to be reexamined. Such canals are not only built aquatic infrastructure, they are also the product of a culture and social relationship with water in the Mediterranean region. Canals form a complex system which is driven by environmental, economic and social factors. Our sociological and environmental research in Provence （and around the Durance basin more specifically） points up how the very dense territorial network of gravity-fed canals is useful in water management, as well as in other shared uses over the long-term. The findings underscore the positive environmental role played by these historical and anthropogenic constructions. They contribute to refilling the aquifer and also act as a valuable environmental good and service （e.g., run-off regulation, biodiversity, landscape, recreation, etc.）. Further, several local actors have underscored their role as part of an intangible cultural heritage and as important for the area＇s economic and social development. Such canals play a central role in sustainable development since beyond their productive role in agriculture, they play a social role （new uses） and an ecological role （as reservoirs for biodiversity and ecological corridors）.     

Assessment of the posterior segment of the cat eye by optical coherence tomography (OCT)

OBJECTIVES: To assess the feasibility of optical coherence tomography (OCT) for examining the cat ocular fundus, to provide normative data on retinal thickness in different fundus regions, and to demonstrate selected surgically induced vitreoretinal pathologies in the cat. ANIMAL STUDIED: Forty-five eyes of 28 healthy domestic cats and two eyes of domestic cats that had undergone subretinal implantation surgery for a visual prosthesis were examined. PROCEDURES: An optical coherence tomograph (Zeiss-Humphrey) was used to examine the anesthetized animals. At least five vertical and five horizontal scans in regular distribution were recorded for each cat including (1) the peripapillary region, (2) the area centralis, and (3) the peripheral retina. Thickness was measured manually at five locations in each scan. Retinal thickness was compared in the three above-mentioned fundus regions, between eyes and between vertical and horizontal scans. OCT was additionally performed in animals with retinal detachment and a subretinal visual prosthesis. RESULTS: OCT measurements required only minimal adjustments of human settings and yielded high quality images. In comparison to humans intraretinal layers were more difficult to differentiate. Retinal thickness was highest in the peripapillary region (245 +/- 21 microm), followed by the peripheral retina (204 +/- 11 microm) and the area centralis (182 +/- 11 microm; all P < 0.0001). There was no statistically significant difference between right and left eye or between vertical and horizontal scans. OCT demonstrated retinal detachment, an iatrogenic break and a subretinal prosthetic device in high detail. CONCLUSIONS: Retinal thickness was measurable with high precision; values compare well to older histologic studies. OCT bears significant advantages over histology in enabling one to repeat measurements in living animals and thus allowing longitudinal studies. Various vitreoretinal pathologies common in feline eyes are detectable and quantifiable by OCT.     

Intracardiac foreign body in a dog

A dog that was referred to the University of Florida Veterinary Medical Center was discovered to have a bamboo skewer within the right atrium and right ventricle, traversing the tricuspid valve. The skewer was ingested approximately four months prior to referral and was partially removed via gastrotomy. The presenting complaint at the time of referral included coagulopathy, anemia and leukocytosis. A linear, hyperechoic structure was identified in the right heart during an echocardiogram. The foreign body was suspected to be a portion of the skewer that the patient had previously ingested. Cardiopulmonary bypass was performed and the foreign body was removed successfully. Complications following surgery included the development of tricuspid valve and ventricular wall thrombi, atrial flutter and amiodarone toxicity. Many indications have been described in the veterinary literature for cardiopulmonary bypass. However, to the best of the authors' knowledge, successful removal of an intracardiac foreign body with cardiopulmonary bypass has not been reported in a veterinary patient. This represents a new indication for cardiopulmonary bypass in veterinary medicine.