Prevalence and antimicrobial resistance of MRSA across different pig age groups in an intensive pig production system in Australia

This observational study aimed to determine MRSA prevalence using strain‐specific real‐time PCR at the pig level, stratified by age groupings, within a pig enterprise. A total of 658 samples were collected from individual pigs (n = 618) and the piggery environment (n = 40), distributed amongst five different pig age groups. Presumptive MRSA isolates were confirmed by the presence of mecA, and MALDI‐TOF was performed for species verification. All isolates were tested against 18 different antimicrobials. MRSA was isolated from 75.2% (95% CI 71.8–78.6) of samples collected from pigs, and 71% of the MRSA isolates from this source were identified as community‐associated (CA)‐MRSA ST93, while the remainder were livestock‐associated (LA)‐MRSA ST398. Amongst environmental isolates, 80% (CI 64.3–95.7) were ST93 and the remainder ST398. All MRSA isolates from pigs and the environment were susceptible to ciprofloxacin, gentamicin, linezolid, mupirocin, rifampicin, sulfamethoxazole–trimethoprim, teicoplanin and vancomycin. Phenotypic rates of resistance were penicillin (100%), clindamycin (97.6%), erythromycin (96.3%), ceftiofur (93.7%), chloramphenicol (81.2%), tetracycline (63.1%) and amoxicillin–clavulanate (63.9%). A low prevalence of resistance (9.2%) was observed against neomycin and quinupristin–dalfopristin. The probability of MRSA carriage in dry sows (42.2%) was found to be significantly lower (p < .001) when compared to other age groups: farrowing sows (76.8%, RR1.82), weaners (97.8%, RR 2.32), growers (94.2%, RR 2.23) and finishers (98.3%, RR 2.33). Amongst different production age groups, a significant difference was also found in antimicrobial resistance for amoxicillin–clavulanate, neomycin, chloramphenicol and tetracycline. Using the RT‐PCR assay adopted in this study, filtering of highly prevalent ST93 and non‐ST93 isolates was performed at high throughput and low cost. In conclusion, this study found that weaner pigs presented a higher risk for CA‐MRSA and antimicrobial resistance compared to other age groups. These findings have major implications for how investigations of MRSA outbreaks should be approached under the One‐Health context.     

Prednisone per os is likely to have limited efficacy in horses

Based on its efficacy for the treatment of human asthma, the corticosteroid prednisone is commonly used in horses for treatment of recurrent airway obstruction. However, recent studies have failed to show any benefit of prednisone tablets for the treatment of this condition. The purpose of this study was to determine why oral prednisone has poor efficacy for the treatment of heaves in horses. In a crossover study, 5 horses were given the following treatments: prednisone tablets, prednisone liquid, prednisolone tablets, prednisolone liquid and i.v. prednisolone sodium succinate (positive control). Blood samples were taken before drug administration and at selected time points during a 24 h period. Serum concentrations of prednisone and prednisolone were determined in order to evaluate gastrointestinal absorption and hepatic metabolism. Serum concentrations of the endogenous glucocorticoid hydrocortisone were also determined as an indicator of the biological activity of the drugs. Both prednisolone tablets and liquid were absorbed rapidly, with prednisolone detectable in serum within 15 min of administration and with peak concentrations occurring within 45 min. Small amounts of prednisone were detected in the serum samples after administration of both prednisone tablets and liquid. Prednisolone was not detected in serum samples after administration of prednisone liquid and was detected in serum samples from only one horse after administration of prednisone tablets. Endogenous hydrocortisone production was suppressed when horses received prednisolone. The results of these studies indicate that prednisone has poor efficacy for the treatment of heaves because it is poorly absorbed and the active metabolite prednisolone is rarely produced. In contrast, prednisolone tablets have excellent bioavailability and should be useful as a therapeutic agent in horses.     

Validation of the 13C-urea breath test for use in cheetahs (Acinonyx jubatus) with Helicobacter.

Historically, therapeutic monitoring for prescribed eradication treatment of Helicobacter in cheetahs (Acinonyx jubatus) with associated gastritis has been accomplished only through endoscopic biopsies. The 13C-urea breath test (UBT) can offer an alternative to repeated biopsies for therapeutic monitoring. Five male and five female cheetahs and one male Sumatran tiger (Panthera tigris) were studied. All were clinically healthy before and after this investigation. Breath samples of end-tidal expiration were taken before and after administration of a 13C-enriched urea solution through a gastroesophageal tube. Twenty-milliliter breath samples were taken at 10, 20, 30, and 40 min after administration of the urea solution. The results of the breath analysis were compared with the results of rapid urease testing, histopathologic examination, and impression smears of gastric biopsies taken at the time of the breath test. The sensitivity and specificity for the 13C-UBT in this investigation were 100%. and the positive predictive value and negative predictive value were both 100%. Although the 13C-UBT is a good noninvasive diagnostic tool for monitoring the presence of Helicobacter sp. in the gastric mucosa, endoscopy should still be used for initial diagnosis and grading of gastritis and for monitoring the progression of disease in cheetahs. The 13C-UBT is a valuable, simple, accurate, and sensitive tool for monitoring eradication of Helicobacter during therapy for clinical gastritis.     

Evaluation of complications and prognostic factors associated with administration of total parenteral nutrition in cats: 75 cases (1994-2001)

OBJECTIVE: To determine frequency and types of complications, prognostic factors, and primary diseases affecting clinical outcome associated with administration of total parenteral nutrition (TPN) in cats. DESIGN: Retrospective study. ANIMALS: 75 cats that received TPN for > or = 12 hours. PROCEDURE: Medical records were reviewed, and information was obtained on signalment, history, problems at initial evaluation, physical examination findings, weight and changes in weight while receiving TPN, duration in the hospital before initiation of TPN, the type of TPN catheter used, duration of TPN administration, and final diagnosis. Laboratory results obtained immediately prior to TPN and at 24 and 96 hours following initiation of TPN administration were compared. RESULTS: Reports of weight loss at initial evaluation, hyperglycemia at 24 hours, or diagnosis of chronic renal failure were significantly associated with increased mortality rate. Greater serum albumin concentrations prior to and at 96 hours following TPN administration were significantly associated with decreased mortality rate. Mechanical and septic complications were infrequent and not associated with increased mortality rate. Most cats had multiple diseases. The overall mortality rate was 52%; among 75 cats, 36 recovered, 23 were euthanatized, and 16 died as a result of their primary illness or complications associated with their illness. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated high mortality rate in cats maintained onTPN that had multiple concurrent diseases associated with a poor prognosis. Indicators of poor prognosis included a history of weight loss, hyperglycemia at 24 hours following TPN administration, hypoalbuminemia, and chronic renal failure.     

Pharmacokinetics of buprenorphine following intravenous and buccal administration in cats,and effects on thermal threshold

This study reports the pharmacokinetics of buprenorphine, following i.v. and buccal administration, and the relationship between buprenorphine concentration and its effect on thermal threshold. Buprenorphine (20 μg/kg) was administered intravenously or buccally to six cats. Thermal threshold was determined, and arterial blood sampled prior to, and at various times up to 24 h following drug administration. Plasma buprenorphine concentration was determined using liquid chromatography/mass spectrometry. Compartment models were fitted to the time–concentration data. Pharmacokinetic/pharmacodynamic models were fitted to the concentration‐thermal threshold data. Thermal threshold was significantly higher than baseline 44 min after buccal administration, and 7, 24, and 104 min after i.v. administration. A two‐ and three‐compartment model best fitted the data following buccal and i.v. administration, respectively. Following i.v. administration, mean ± SD volume of distribution at steady‐state (L/kg), clearance (mL·min/kg), and terminal half‐life (h) were 11.6 ± 8.5, 23.8 ± 3.5, and 9.8 ± 3.5. Following buccal administration, absorption half‐life was 23.7 ± 9.1 min, and terminal half‐life was 8.9 ± 4.9 h. An effect‐compartment model with a simple effect maximum model best predicted the time‐course of the effect of buprenorphine on thermal threshold. Median (range) k_e0 and EC50 were 0.003 (0.002–0.018)/min and 0.599 (0.073–1.628) ng/mL (i.v.), and 0.017 (0.002–0.023)/min and 0.429 (0.144–0.556) ng/mL (buccal).     

Schirmer tear tests and intraocular pressures in conscious and anesthetized koalas (Phascolarctus cinereus)

Objective To estimate mean Schirmer tear test (STT) and intraocular pressure (IOP) values in healthy koalas both conscious and anesthetized. Methods Data were gathered from koalas in Victoria, Australia. Conscious examinations were performed on captive koalas. Free‐ranging (wild) koalas were examined under anesthesia. Anesthesia was induced using alfaxalone, and animals were maintained on oxygen and isoflurane if required. All animals were healthy and had no surface ocular pathology detectable during slit lamp biomicroscopy. STT I tests were performed using commercial STT test strips placed in the lower fornix for 1 min. IOP was measured using an applanation tonometer after topical anesthesia. The higher value of the two eyes for both STT and IOP was analyzed. STT was measured in 53 koalas (34 conscious, 19 anesthetized) and IOP was measured in 43 koalas (30 conscious, 13 anesthetized). A two‐sample t‐test was used to compare means. A P‐value <0.05 was regarded as significant. Mean ± SD is presented. Results The mean higher STT in conscious koalas was 10.3 ± 3.6 mm wetting/min and in anesthetized koalas it decreased to 3.8 ± 4.0 mm wetting/min (P < 0.0001). The mean higher IOP in conscious koalas was 15.3 ± 5.1 mmHg, and in anesthetized koalas it was 13.8 ± 3.4 mmHg (P = 0.32). There was no effect of sex on either STT or IOP. Conclusions The mean and SD of STT and IOP values for koalas both conscious and anesthetized were reported. The mean STT was significantly reduced by alfaxalone anesthesia.     

Stratum corneum removal facilitates experimental sensitization to mite allergens in atopic dogs

In humans with atopic dermatitis and in mouse models of IgE-mediated allergic diseases, evidence is mounting that the stratum corneum (SC) provides an important barrier against environmental allergens. At this time, it is not known whether the SC has a similar role in dogs, especially in those with atopic dermatitis. The objectives of this pilot study were to determine whether SC removal led to earlier and stronger sensitization of atopic dogs to Dermatophagoides farinae (Df) house dust mites. Five Maltese-beagle atopic (MBA) dogs were sensitized epicutaneously after the SC was removed with ten tape strips (TS group), while sensitization was done without tape strips in five other MBA dogs (nontape stripping; NTS group). During this 16 week study, sensitization was assessed with allergen-specific IgE serology, intradermal testing with Df allergens and determination of stimulation indices of blood mononuclear cells cultured with Df and stained for CD4 and the activation markers CD25 or CD30. Compared with dogs from the NTS group, those of the TS group exhibited earlier rises in Df-specific IgE serum levels, usually had higher allergen-specific IgE titres, showed higher intradermal test reactivity and had earlier increases and higher percentages of CD25- or CD30-positive activated allergen-specific peripheral CD4-positive T lymphocytes. These observations implicate a role of the SC as a barrier limiting sensitization to exogenous allergens in this experimental atopic dog model.