Australian Veterinary Journal最新文献

A healthy chicken's intestinal flora harbours a rich reservoir of Escherichia coli as part of the commensal microbiota. However, some strains, known as avian pathogenic E. coli (APEC), carry specific virulence genes (VGs) that enable them to invade and cause extraintestinal infections such as avian colibacillosis. Although several VG combinations have been identified, the pathogenic mechanisms associated with APEC are ill-defined. The current study screened a subset of 88 E. coli isolates selected from 237 pre-existing isolates obtained from commercial poultry flocks in Australia. The 88 isolates were selected based on their enterobacterial repetitive intergenic consensus (ERIC) and antimicrobial resistance (AMR) profiles and included 29 E. coli isolates cultured from chickens with colibacillosis (referred to as clinical E. coli or CEC) and 59 faecal E. coli (FEC) isolates cultured from clinically healthy chickens. The isolates were screened for the presence of 35 previously reported VGs. Of these, 34 were identified, with iucA not being detected. VGs focG, hlyA and sfa/foc were only detected in FEC isolates. Eight VGs had a prevalence of 90% or above in the CEC isolates. Specifically, astA (100%); feoB (96.6%); iutA, iss, ompT, iroN and hlyF (all 93.1%); and vat (89.7%). The prevalence of these were significantly lower in FEC isolates (astA 79.7%, feoB 77.9%, iutA 52.5%, iss 45.8%, ompT 50.9%, iroN 37.3%, hlyF 50.9% and vat 42.4%). The odds ratios that each of these eight VGs were more likely to be associated with CEC than FEC ranged from 7.8 to 21.9. These eight VGs may be used to better define APEC and diagnostically detect APEC in Australia. Further investigations are needed to identify the roles of these VGs in pathogenicity.

Canine adrenal gland volume can be predicted based on body weight and computed tomography (CT) measurements using a validated algorithm. Use of this algorithm to detect adrenal pathology, including hyperplasia, hypoplasia and neoplasia, in clinical cases has not been described. The objective of this study was to illustrate application of the algorithm by estimating subject-specific adrenal gland volume in a historical cohort of dogs with known adrenal disease. Forty-six dogs that underwent CT and subsequent adrenalectomy were included. Clinical records and CT images from dogs that underwent adrenalectomy and histologic examination of the excised adrenal gland(s) were reviewed. Normal adrenal gland volumes for each dog were estimated using the algorithm, and compared with measured volumes of the affected glands. Linear measurement of the largest lesion diameter was also recorded. Fifty-eight adrenal glands were removed from 46 dogs, with pathology confirmed in all glands. Pathology included 28 adenomas, 13 carcinomas, 11 pheochromocytomas and 6 other benign pathologies. The volume of all removed adrenal glands was measured to be larger than the expected normal volume estimated by the algorithm, ranging from 1.1 to 212.9 times larger than estimated. Adrenal glands with malignant and benign pathology showed variable volumes with overlapping ranges recorded. Assessment of the dimensions of any focal lesion against a cut-off of 20 mm failed to discriminate malignancy. This study illustrates and supports the application of a validated volumetric algorithm for estimation of subject-specific adrenal gland volume to identify the presence of pathology and as a tool to assist clinical decision-making.

Urinary tract infections are a common diagnosis in dogs presenting to veterinary practice. Veterinarians often treat suspected infections empirically, either in the absence of culture and susceptibility testing results or whilst waiting for them. This study aimed to identify the bacteria most frequently isolated from canine urinary samples and their antimicrobial susceptibility patterns in South East Queensland (SEQ) to help guide responsible empirical antimicrobial prescription by the veterinary community in this geographical location. Cumulative antibiograms were generated from the results of 1284 culture-positive urinary samples in SEQ, obtained from a commercial veterinary laboratory over a 5-year period. Escherichia coli was the most commonly isolated bacterial species (43%), followed by Staphylococcus spp. (23%), Proteus spp. (21%) and Enterococcus spp. (10%). Of the six most common isolates, 97% had susceptibility to at least one low-importance antimicrobial. Susceptibility to the low-importance and first-line antimicrobial recommendation, amoxicillin, was 81% for E. coli and 24% for Staphylococcus spp. Susceptibility of both E. coli and Staphylococcus spp. to medium-importance and commonly recommended empirical antimicrobials, trimethoprim sulphonamides and amoxicillin–clavulanic acid was ≥85% and >92% for high-importance antimicrobials enrofloxacin and ceftiofur. Of the E. coli and Staphylococcus spp. isolates, 8.8% and 4%, respectively, were considered multidrug resistant. There was no increase in resistance to antimicrobials detected over the study period. Susceptibilities suggest low- and medium-importance antimicrobials remain acceptable first-line empirical treatments. However, this should be continually assessed and updated using local surveillance data.

Cryptococcus is an encapsulated yeast that is found in both yeast and hyphal forms. Cryptococcus neoformans and C. gattii are the most medically important species, causing disease in both immunocompromised and immunocompetent individuals. A large, friable, sublingual mass was surgically resected from the oral cavity of a pink-tongued skink (Cyclodomorphus gerarrdii). Histopathology, fungal culture and PCR testing with Sanger sequencing confirmed granulomatous inflammation containing large numbers of yeasts identified as Cryptococcus neoformans var. grubii. Surgical excision and treatment with oral amphotericin B and terbinafine was unsuccessful in managing the infection. On Day 67 after surgery, Cryptococcus DNA was detected by PCR in the blood but not oral, cloacal or skin swabs. The skink was euthanised 72 days after surgery due to anorexia, weight loss and progressive neurological signs of disease. Necropsy results showed disseminated cryptococcosis, including meningoencephalitis and ventriculitis. Two in-contact pink-tongued skinks remained asymptomatic and PCR-negative during 198 days of observation. This case suggests Cryptococcus infections should be considered for oral masses presenting with or without neurological signs in skinks. Further investigation is required to determine the best treatment options for disseminated cryptococcosis in reptiles. This report describes the third reported case of Cryptococcus in a reptile and the first case of cryptococcosis in a pink-tongued skink. It is also the first report of Cryptococcus in a reptile identified to the variety level using PCR, including in whole blood samples.

Research and enquiry (R&E) is an integral part of veterinary training. It is a foundation of evidence-based practice. In the University of Sydney Doctor of Veterinary Medicine degree R&E culminates in a cap-stone experience in Year 3: a ‘professionally focused project’, a student-driven and academic supported individual research project. The project provides an authentic experience within a veterinary discipline. Students work with an academic advisor who provides guidance for developing and achieving meaningful educational and professional goals. Successful advising depends upon a shared understanding of, and commitment to, the advising process by students, advisors and the university. The R&E mission can be broadly defined as - veterinarians recognise that evidence-based approach to practice, which is based on the scientific method, leads to the generation of new knowledge that underpins the veterinary medical profession.

Although cryptococcosis is the most common systemic fungal disease of cats, abdominal involvement is rarely reported. The pathogenesis of cryptococcosis usually involves sinonasal colonisation, followed by tissue invasion and sinonasal infection, with possible subsequent spread to the lungs and/or direct extension into the central nervous system (CNS), for example, via the cribriform plate. Further haematogenous spread can occur to any tissue, including skin and the CNS. This report describes a case of disseminated cryptococcosis due to Cryptococcus neoformans species complex in a 13-year-old cat, the fourth documented Australian feline case with abdominal involvement. The cat presented with a chronic history of upper respiratory disease that progressed to severe lethargy and anorexia. An autopsy revealed striking peritonitis with multifocal abdominal involvement affecting the liver, spleen, adrenal glands, kidneys, pancreas and mesentery. Cryptococcal organisms were also observed in organs within the thoracic cavity, sinonasal tissues and the CNS. Testing of abdominal fluid and serum for cryptococcal antigen using a commercially available lateral flow assay using neat fluid specimen initially tested false-negative. However, after dilution of the sample to 1:64, a positive result was obtained, confirming a postzone phenomenon. Taken together, the collective findings were indicative of widely disseminated cryptococcosis due to Cryptococcus neoformans with atypical involvement of the abdominal cavity.

Strongyloides stercoralis is parasite affecting both humans and dogs and is most prevalent in tropical and subtropical areas of Australia. This case report describes two dogs from a household in Sydney, New South Wales, one with chronic gastrointestinal signs and the other who was asymptomatic who were subsequently diagnosed with S. stercoralis. Diagnosis can be challenging in humans and dogs due to intermittent shedding and low worm burdens and in this case the symptomatic dog had Strongyloides spp. rhabitiform larvae detected on a direct faecal smear and PCR, the asymptomatic dog on PCR only. Obtained sequences from the symptomatic dog confirmed the presence of the S. stercoralis clade affecting both dogs and humans. Infection does not respond to commonly used deworming drugs for dogs. Treatment in both cases was undertaken using off-label doses of ivermectin and follow-up PCR testing was negative. This case report should increase practitioner awareness of this parasite as present and transmissible in temperate areas of Australia.