Case report and successful management of canine aortic endocarditis caused by Actinomyces neuii subsp. anitratus (Winkia neuii subsp. anitrata).

BACKGROUND: Canine aortic valve endocarditis carries a poor prognosis. In the current literature there are only two reports of infectious endocarditis associated with Actinomyces; Actinomyces turicensis and an Actinomyces-like organism. Endocarditis due to Actinomyces neuii subsp. anitratus (now known as Winkia neuii subsp. anitrata) has rarely been reported in humans, and to the best of our knowledge, has never been reported in dogs. CASE PRESENTATION: A 4 year-3 months old female neutered Great Dane presented with lethargy, hyporexia, 'praying position' stance, acute onset of cherry eye and pyrexia. A subtle diastolic heart murmur was detected on thoracic auscultation and echocardiology revealed an irregular lesion adhered to the ventricular aspect of the aortic valve, suggestive of aortic valve endocarditis. Peripheral blood was collected for blood culture. Following 10 days of incubation, blood cultures yielded a growth of aerobic gram-positive filamentous rods which were further biochemically (BioMerieux API Coryne profiling strip) identified as Actinomyces neuii subsp. anitratus. The patient was treated with marbofloxacin and amoxicillin/clavulanic acid for five consecutive months. On repeat echogram, following treatment completion, there was no evidence of aortic valve endocarditis. To the best of our knowledge this is the first case report documenting successful treatment of aortic valve endocarditis caused by Actinomyces neuii subsp. anitratus in a dog. CONCLUSIONS: Despite the poor prognosis of canine infectious aortic valve endocarditis, patients with Actinomyces neuii subsp. anitratus infection might have a favourable outcome. It is therefore important identifying the underling infectious cause, as it may have a significant impact on prognosis and treatment outcome when it is caused by Actinomyces neuii subsp. anitratus.

Actinomycosis in a gray four-eyed opossum (Philander opossum) caused by a novel species of Schaalia.

BACKGROUND: Infective lesions of the jaws and adjacent tissues (lumpy jaw disease, LJD) have been recognized as one major cause of death of captive macropods. Fusobacterium necrophorum and Actinomyces species serve as the main source of LJD in kangaroos and wallabies. Currently, little is reported about LJD or similar diseases in opossums. CASE PRESENTATION: Here we report a case of actinomycosis resembling the entity lumpy jaw disease in a gray four-eyed opossum, caused by a novel species of Schaalia. A 2.8 year old male Philander opossum was presented with unilateral swelling of the right mandible. After an initial treatment with marbofloxacin, the opossum was found dead the following day and the carcass was submitted for necropsy. Postmortem examination revealed severe mandibular skin and underlying soft tissue infection with subsequent septicemia as the cause of death. Histological examination demonstrated Splendore-Hoeppli phenomenon, typically seen in classical cases of actinomycosis. Bacteriology of liver and mandibular mass yielded a previously undescribed species of Schaalia, whose 16 S rRNA gene sequence was 97.0 % identical to Schaalia canis. Whole genome sequencing of the opossum isolate and calculation of average nucleotide identity confirmed a novel species of Schaalia, for which no whole genome sequence is yet available. CONCLUSIONS: The herewith reported Schaalia infection in the gray four-eyed opossum resembling classical actinomycosis gives a novel insight into new exotic animal bacterial diseases. Schaalia species may belong to the normal oral microbiome, as in macropods, and may serve as a contributor to opportunistic infections. Due to the lack of current literature, more insights and improved knowledge about Schaalia spp. and their pathogenicity will be useful to choose appropriate therapy regimens and improve the treatment success rate and outcome in exotic and endangered species.

Pulmonary Actinomycosis in South Australian Koalas (Phascolarctos cinereus).

Pneumonia has been reported in both free-ranging and captive koalas and a number of causative agents have been described. Between 2016 and 2019, 16 free-ranging and 1 captive koala (Phascolarctos cinereus) from the Mount Lofty Ranges of South Australia were identified with pyogranulomatous lobar pneumonia, which involved the left caudal lobe in 14/17 (82%) cases. Within lesions, numerous gram-positive or gram-variable, non-acid-fast filamentous bacteria were observed in association with Splendore-Hoeppli phenomenon. Culture yielded growth of anaerobic bacteria, which were unidentifiable by MALDI-TOF-MS (matrix-assisted laser desorption ionization-time of flight mass spectrometry) analysis in 5/5 cases. Sequencing of the bacterial 16S rRNA gene identified a novel Actinomyces species in 4 samples, confirming a diagnosis of pulmonary actinomycosis. Concurrent examination of resin lung casts from healthy koalas suggested greater laminar flow of air to the left caudal lung lobe in koalas. Actinomyces spp. have been reported as commensals of the oral microbiome in other species, and an association with similar pulmonary lesions in other species. Considering the predilection for involvement of the left caudal lung lobe, aspiration is suggested as the likely cause in some cases of pulmonary actinomycosis in koalas. Pulmonary actinomycosis has not been previously described in koalas and further work needs to be undertaken in order to classify this organism within the Actinomyces genus.

Hypertrophic osteopathy in South Australian koalas (Phascolarctos cinereus) with concurrent pulmonary actinomycosis.

Pulmonary actinomycosis is described in 17 South Australian koalas necropsied between 2016 and 2019. From these cases, four koalas had secondary hypertrophic osteopathy. Plain radiographical and computed tomography images demonstrated periosteal reaction on multiple appendicular skeletal bones in all cases, including scapula, humerus, ulna, radius, ilium, femur, tibia, fibula, metacarpus, metatarsus and phalanx. Grossly, periosteal surfaces of the metaphyses and diaphyses of long bones were thickened and roughened; microscopically, this was characterised by bi-layered proliferation of well-differentiated trabecular bony spicules oriented perpendicular to the cortex (pseudocortices) and separated by vascular connective tissue, typical for hypertrophic osteopathy. Well characterised in domestic species and rarely reported in marsupials, this is the first radiographical and pathological characterisation of hypertrophic osteopathy in koalas, associated with pulmonary actinomycosis in all cases.

Pulmonary actinomycosis in a free-living black-tufted marmoset (Callithrix penicillata).

Actinomycosis is a very rare infection in wild animals with a few reports in captive non-human primates. Herein we report a case of pulmonary actinomycosis in a free-living black-tufted marmoset in the urban area of the Federal District, Brazil. The animal presented severe dyspnea and died in the garden of a residence. At necropsy, the left-pulmonary lobes showed multiple nodules filled with purulent content. A myriad of beaded, branching, filamentous Gram-positive and modified Ziehl-Neelsen-negative bacilli arranged in aggregates or star-like colonies, surrounded by macrophages, neutrophils, and Splendori-Hoepli phenomenon were observed in histological sections of the lungs. According to the pathological findings and characteristic morphotintorial pattern of the infectious agent, pulmonary actinomycosis was diagnosed. Until now, fatal pulmonary actinomycosis had never been reported in free-living Simiiformes. Knowledge about the diseases that affect commensal free-range simians in urban areas forms the basis for actions aimed at conservation of the species.

REPEATED ANESTHESIA IN A BLACK RHINOCEROS ( DICEROS BICORNIS) TO MANAGE UPPER RESPIRATORY OBSTRUCTION.

This report describes weekly repeated anesthesia in a 7-yr-old, 1,030 kg, female Eastern black rhinoceros ( Diceros bicornis michaeli), that was immobilized six times using a combination of 2 mg etorphine (0.002 mg/kg), 5 mg medetomidine (0.005 mg/kg), 25 mg midazolam (0.024 mg/kg), and 300 mg ketamine (0.29 mg/kg) delivered intramuscularly (IM) via remote dart to facilitate long-term medical care of a bilateral, obstructive Actinomyces sp. rhinitis. The drug combination described in this study resulted in reliable, rapid recumbency of the animal within 2-8 min after initial administration via dart and produced deep anesthesia for 34-78 min without supplemental anesthetic administration. Antagonist drugs (100 mg naltrexone [0.1 mg/kg] and 25 mg atipamezole [0.024 mg/kg] IM) produced reliable and uneventful recoveries in all the procedures. During each anesthetic procedure, the animal was intubated and provided intermittent positive pressure ventilation with a megavertebrate demand ventilator. Tachycardia and hypoxia noted after induction resolved after positive pressure ventilation with oxygen. This report provides useful information on a novel anesthetic protocol used repeatedly for intensive medical management in a black rhinoceros.

Actinomyces denticolens as a causative agent of actinomycosis in animals.

The name "Actinomyces suis" was applied to each actinomycete isolate from swine actinomycosis by Grässer in 1962 and Franke in 1973. Nevertheless, this specific species was not included in the "Approved List of Bacterial Name" due to absence of the type cultures. Therefore, "Actinomyces suis" based on the description of Franke 1973 has been considered as "species incertae sedis". We isolated a number of Actinomyces strains from swine. The representative strains of them was designated as Chiba 101 that was closely similar to the description in "Actinomyces suis" reported by Franke in 1973. Interestingly, it was found that the biological characteristics of these strains were also very similar to those of Actinomyces denticolens. Furthermore, the average nucleotide identity (ANI) value between strain Chiba 101 and the type-strain of Actinomyces denticolens (=DSM 20671T) was found to be 99.95%. Sequences of the housekeeping genes and 16S rRNA gene showed 100% homology. These results strongly suggested that "Actinomyces suis" Franke 1973 is the same species as Actinomyces denticolens. Since actinomycosis caused by Actinomyces denticolens have been demonstrated in horses recently, it is necessary to recognize that Actinomyces denticolens is the pathogenic actinomycetes in broader range of animals.

Diagnosis and management of pyothorax in a domestic ferret (Mustela putorius furo).

OBJECTIVE: To describe the diagnosis, management, and outcome of pyothorax in a domestic ferret (Mustela putorius furo). CASE SUMMARY: A domestic ferret was evaluated for a history of lethargy, anorexia, and pyrexia. Pleural effusion was detected with radiography and ultrasonography, and a diagnosis of pyothorax was made following cytologic evaluation of pleural fluid. Bilateral thoracostomy tubes were placed for thoracic drainage and lavage, and the ferret was treated with intravenous crystalloid fluids, antimicrobials, and analgesics. Bacterial culture of the pleural fluid yielded Fusobacterium spp. and Actinomyces hordeovulneris. This treatment protocol resulted in resolution of pyothorax, and a positive clinical outcome. NEW OR UNIQUE INFORMATION PROVIDED: This is the first reported case of successful management of pyothorax caused by Fusobacterium spp. and A. hordeovulneris in a ferret.

Successful treatment of mitral valve endocarditis in a dog associated with 'Actinomyces canis-like' infection.

Infective endocarditis, an inflammation of the endocardial surface due to invasion by an infectious agent, is more common in middle sized to large breed dogs. We herein report a case of mitral valve endocarditis in a 9-year-old male-castrated Weimaraner caused by an Actinomyces canis-like bacterium, not previously reported in association with infection in dogs.

Actinomicose atípica em bovinos / Atypical actinomycosis in cattle

Casos de actinomicose com apresentação atípica são descritos em dois bovinos. Em ambos os casos notou-se uma aumento de volume extenso e duro na maxila. A maxila dos dois bovinos tomou um aspecto de favo de mel como resultado da rarefação destrutiva e da proliferação óssea regenerativa. Na superfície de corte as lesões consistiam de tecido fibroso branco e brilhante em meio ao qual numerosos grânulos amarelos podiam ser vistos. Tratos fistulosos podiam ser demonstrados em meio às lesões. Em cortes corados pela hematoxilina e eosina as lesões consistiam de ilhas de inflamação piogranulomatosa em meio a extenso estroma fibroso. No centro do granuloma havia uma massa basofílica de forma irregular cercada por uma zona com projeções eosinofílicas radiadas (reação de Splendore-Hoeppli). Ao redor da massa radiada havia uma zona de neutrófilos cercada por uma camada de macrófagos epitelioides e ocasionais células gigantes multinucleadas. Uma camada externa de linfócitos e plasmócitos limitava o granuloma do extenso estroma conjuntivo que o cercava. Na coloração de Gram, a parte central da colônia revelava um aglomerado de micro-organismos em forma de bastonetes, com morfologia compatível com Actinomyces bovis. Uma vez que a apresentação pouco usual das lesões levou a má interpretação diagnóstica inicial nestes casos, a descrição detalhada das lesões é feita aqui com o objetivo de ajudar no diagnóstico diferencial feito por veterinários clínicos e inspetores de carne.

Cases of actinomycosis with atypical presentation are described in two oxen. In both cases there was a hard irregular and extensive lesions in the maxilla. The maxilla of both cattle became enlarged and honeycombed as a result of destructive rarefaction and regenerative bone proliferation. The cut surface of the lesions consisted of white glistening fibrous tissue within which numerous yellow caseous granules could be seen. Sinus tracts could be demonstrated within the lesions. In hematoxylin-eosin stained sections the lesions consisted of island of pyogranulomatous inflammation within an extensive fibrous stroma. In the center of the granuloma there was a basophilic irregular shaped mass surrounded by a zone radially arranged eosinophilic projections (Splendore-Hoeppli material). Around the radiating mass there was a zone of neutrophils, surrounded by a layer of epithelioid macrophages and occasional multinucleated giant cells. An outer layer of lymphocytes and plasma cells was present that limit the granuloma from the abundant fibrous tissue surrounding it. Up on Gram stain the central part of the colony revealed a tangled mass of rod shaped organisms morphologically consistent with Actinomyces bovis. Since the unusual presentation of this lesions misled the initial diagnosis the detailed description of these cases are reported here in the hopes it can help in the differential diagnosis by veterinary practitioners and met inspectors.

Presence of Escherichia coli, Trueperella pyogenes, α-hemolytic streptococci, and coagulase-negative staphylococci and prevalence of subclinical endometritis.

Subclinical endometritis (SCE) has a severe negative effect on reproductive performance of dairy cows. Different studies have shown a wide variety of cut points for the polymorphonuclear neutrophilic leukocyte (PMNL) percentage to define SCE and differing sampling times. Possible risk factors for SCE, such as low body condition score, hyperketonemia, and increased haptoglobin concentrations have been demonstrated. The aim of this study was to determine the relationship between bacterial findings in the uterus and PMNL in the early postpartum period and to compare 2 classification schemes for the diagnosis of SCE. Cytological and bacteriological samples from the uterus were taken from 149 cows at 2 consecutive times postpartum [10 ± 1 and 24 ± 1 d in milk (DIM)] and additionally, 131 cows were sampled at 21 to 27 DIM. For sample collection, the cytobrush technique was used and vaginal discharge was examined by vaginoscopy. Polymorphonuclear neutrophilic leukocyte cut points were set at 5, 10, and 18%. Cows positive with α-hemolytic streptococci at 10 ± 1 DIM had significant higher PMNL percentages at 21 to 27 DIM and greater median days to pregnancy (193.5d) than cows not infected (123.0 d). Cows with Trueperella pyogenes at 10±1 DIM had higher odds (5.2) of having more than 18% PMNL at 21 to 27 DIM compared with cows without infection. Escherichia coli had no effect on the prevalence of SCE regardless of the cut point. Primiparous cows with more than 18% PMNL had greater median days to pregnancy (144.5 d) than cows with less than 5% (80.0 d) or cows between 5 and 18% PMNL (68.0 d). Cows between 5 and 18% PMNL or 10 and 18% PMNL showed the best reproductive performance. The results demonstrate that an early infection with α-hemolytic streptococci increased the PMNL percentage 2 wk later and that 18% PMNL at 21 to 27 DIM was a predictive cut point for primiparous cows to diagnose animals with or without SCE.

Actinomyces endogenous endophthalmitis in a cat following multiple dental extractions.

An 8-year-old, brachycephalic, mixed breed cat underwent full mouth tooth extractions for the treatment of tooth root abscessation. Subsequently, the cat developed anterior uveitis refractory to topical therapy that eventually necessitated enucleation. Actinomyces species were isolated from both the tooth root abscesses and the anterior chamber after enucleation. Histopathology of the enucleated eye revealed panophthalmitis with abundant intralesional bacteria morphologically consistent with Actinomyces. Between the time of tooth root extraction and enucleation (20 weeks), the cat was diagnosed with hyperthyroidism and treated with oral steroids for inflammatory bowel syndrome. We believe this report represents a rare case of endogenous endophthalmitis secondary to dental disease, possibly precipitated by concurrent immunosuppression.

Actinomyces bowdenii ulcerative keratitis in a dog.

A 5-year-old spayed female diabetic mixed-breed dog underwent phacoemulsification and intraocular lens implantation to correct bilateral hypermature cataracts. Two months postsurgery, the patient presented with ulcerative keratitis and multifocal stromal abscessation OD, which was controlled, but never resolved, with topical fluoroquinolone therapy. The patient re-presented 2 months later with a new, raised, white gritty corneal opacity associated with hyperemia, chemosis, and blepharospasm OD. Cytology of the right cornea revealed filamentous bacteria, suggestive of Actinomyces spp. Actinomyces bowdenii was subsequently isolated in pure culture and identified via 16s rDNA sequencing. Actinomyces bowdenii has never before been described as a cause of ocular infection. An immunosuppressed corneal environment likely contributed to this opportunistic Actinomycosis. The infection was not controlled with fluoroquinolone therapy, and the isolate, in vitro, was resistant to three fluoroquinolones (ciprofloxacin, ofloxacin, and levofloxacin), which also has not been previously reported for this species of Actinomyces. A superficial keratectomy with conjunctival graft was employed to successfully manage the infection.

Further characteristics of Actinomyces weissii, a novel species isolated from the oral cavity of dogs.

Comparable to previously conducted phenotypical and genotypical investigations (Hijazin et al., 2011c), three strains of the newly described species Actinomyces weissii, isolated from infections of the oral cavity of three dogs could be classified by matrix-assisted laser desorption ionization-time of flight mass spectrometry and by sequencing the target genes 23S rDNA and cpn60 as novel species of genus Actinomyces. The detection of peptidic spectra and both genotypic approaches might help to identify A. weissii in future and elucidate the role this species plays in infections of dogs.

Pleural actinomycosis in a free-ranging river otter (Lontra canadensis).

Actinomycosis, presenting as chronic proliferative pyogranulomatous pleuritis associated with sulfur granules, was diagnosed in a mature male river otter (Lontra canadensis) captured near Victoria, British Columbia, Canada, in April 2010. The river otter died during sedation for clinical examination and was necropsied immediately. Bacteria of the genus Actinomyces are commensals of the mucous membranes in a wide range of animals and people that act as opportunistic pathogens. This is the first report of actinomycosis in a river otter.

Submandibular lymph node abscess caused by Actinomyces denticolens in a horse in Ontario.

This is the first report of the isolation of Actinomyces denticolens, an opportunistic pathogen, from a draining submandibular lymph node abscess in a horse in Ontario. Due to the similarity of the clinical signs with strangles, this pathogen should be included in the differential diagnosis of submandibular lymphadenopathy in the horse.

Intra-thoracic pyogranulomatous disease in four working dogs.

CASE HISTORY: Four working dogs were presented to veterinary clinics in New Zealand for weight loss or swelling of the thoracic wall. All dogs were large-breed males between the ages of 4 and 7 years, and actively involved in farm work. The two dogs with swelling of the thoracic wall had recent histories of work-related trauma. CLINICAL FINDINGS AND DIAGNOSIS: All four dogs were diagnosed with intra-thoracic pyogranulomatous disease via diagnostic imaging and surgical exploration. Two dogs had confirmed infection with Actinomyces viscosus, while a third had suspected Actinomyces or Nocardia spp. infection. The fourth dog had a streptococcal infection, and a grass-seed foreign body was removed at surgery. Two dogs successfully returned to work, however euthanasia was requested by the owners of the other two, either during surgery, due to intra-thoracic haemorrhage, or shortly after, with post-operative meningitis. CLINICAL RELEVANCE: Due to the high value of working dogs in New Zealand, and the higher-than-average risk profile for intra-thoracic pyogranulomatous disease, veterinarians should be aware of this syndrome, and should seek to appropriately diagnose and aggressively treat it surgically.

Granulomatous inflammation in retropharyngeal lymph nodes of wild cervids in Saskatchewan.

A portion of retropharyngeal lymph nodes from 6,824 wild cervids, comprising 1,458 white-tailed deer (Odocoileus virginianus), 5,345 mule deer (Odocoileus hemionus), 11 unidentified deer (Odocoileus spp.), and 10 elk (Cervus elaphus), were examined histologically for evidence of inflammation. Focal granulomatous lymphadenitis was detected in 0.3% of white-tailed deer, 1.3% of mule deer, and in one of 10 elk. Material consistent with Splendore-Hoeppli phenomenon was present in 70 (93%) of 75 cases of lymphadenitis. Replicate sections stained with Gram, acid fast, and methenamine silver stains were examined for organisms. Organisms morphologically consistent with Actinomyces spp. were found in one white-tailed deer; no organisms were detected in any of the other cases of lymphadenitis. Aerobic and anaerobic culture from frozen tissue from the lymph nodes was negative, as was polymerase chain reaction (PCR) for Mycobacterium spp. and Mycobacterium bovis. The method of sampling likely underestimated the prevalence of lymphadenitis.