Mary Leissinger

Investigating the Role of Nucleotide-Binding Oligomerization Domain–Like Receptors in Bacterial Lung Infection

Lower respiratory tract infections (LRTIs) are a persistent and pervasive public health problem worldwide. Pneumonia and other LRTIs will be among the leading causes of death in adults, and pneumonia is the single largest cause of death in children. LRTIs are also an important cause of acute lung injury and acute exacerbations of chronic obstructive pulmonary disease. Because innate immunity is the first line of defense against pathogens, understanding the role of innate immunity in the pulmonary system is of paramount importance. Pattern recognition molecules (PRMs) that recognize microbial-associated molecular patterns are an integral component of the innate immune system and are located in both cell membranes and cytosol. Toll-like receptors and nucleotide-binding oligomerization domain-like receptors (NLRs) are the major sensors at the forefront of pathogen recognition. Although Toll-like receptors have been extensively studied in host immunity, NLRs have diverse and important roles in immune and inflammatory responses, ranging from antimicrobial properties to adaptive immune responses. The lung contains NLR-expressing immune cells such as leukocytes and nonimmune cells such as epithelial cells that are in constant and close contact with invading microbes. This pulmonary perspective addresses our current understanding of the structure and function of NLR family members, highlighting advances and gaps in knowledge, with a specific focus on immune responses in the respiratory tract during bacterial infection. Further advances in exploring cellular and molecular responses to bacterial pathogens are critical to develop improved strategies to treat and prevent devastating infectious diseases of the lung.

Fungal myocarditis and pericardial effusion secondary to Inonotus tropicalis (phylum Basidiomycota) in a dog.

Fungal disease is a rare cause of pericardial effusion in dogs. This report describes the first case of fungal pericardial effusion and myocarditis secondary to the fungal organism Inonotus tropicalis. A 9-year-old female spayed French bulldog with a multi-year history of treatment with glucocorticoids for management of atopy was presented for exercise intolerance, ascites and weight loss. Physical examination and thoracic imaging revealed enlarged peripheral and cranial mediastinal lymph nodes, left ventricular thickening and cardiac tamponade secondary to pericardial effusion. Fine needle aspiration of the cranial mediastinal lymph node showed pyogranulomatous inflammation with short, thin and poorly septated hyphae. Culture of the aspirate yielded a fungal isolate identified as Inonotus tropicalis based on morphologic features and rRNA gene sequencing. Postmortem examination showed myocardial thickening with multifocal to coalescing, firm, white, ill-defined nodules. Histology confirmed the presence of disseminated fungal infection with extensive myocardial involvement. Inonotus tropicalis is an opportunistic poroid wood-decaying basidiomycete. Infection in this dog was likely the result of chronic immunosuppressive therapy.

Disseminated histoplasmosis (Histoplasma capsulatum) in a pet rabbit: case report and review of the literature

A 2.5-year-old intact male miniature lop rabbit (Oryctolagus cuniculus) was presented with multiple nodules surrounding the eyes, nose, mouth, and prepuce. Cytological evaluation of the periocular nodules revealed the presence of intracellular (within macrophages) and extracellular yeast organisms. The yeast organisms were approximately 3–5 µm in diameter, round to oval, with a thin clear capsule, and contained an eccentrically placed basophilic crescent-shaped nucleus. The clinical pathological interpretation was granulomatous inflammation with intralesional yeast of a morphology consistent with Histoplasma spp. The rabbit was treated with microsized griseofulvin (25 mg/kg, orally, once a day) for 12 days pending final cytological diagnosis of histoplasmosis. No significant improvement was noted during the treatment period, and humane euthanasia was performed. Postmortem examination revealed the presence of intracellular and extracellular yeast organisms in the small intestine, skin (antebrachium, perioral, palpebral, perianal, and pinnal), penis, penile urethra, rectum, axillary lymph node, and conjunctiva. Postmortem fungal culture yielded Histoplasma capsulatum. Based on clinical and postmortem findings, a definitive diagnosis of disseminated histoplasmosis was made. Disseminated histoplasmosis appears to be unreported in rabbits. Although the treatment used did not provide noticeable improvement, available information on histoplasmosis treatment in other species has been reviewed to provide useful information for future management of this condition in rabbits.

What is your diagnosis? Blood smear from a cat

A 2-year-old male neutered Domestic Shorthair cat was presented to the emergency medicine service of the Louisiana State University veterinary teaching hospital for acute onset of cluster seizures. The cat presented in lateral recumbency with prolonged capillary refill time (> 2 seconds) and hypothermia (96.7 F/35.9°C). Neurologic examination revealed obtunded mentation, anisocoria, opisthotonus, and lack of menace and palpebral reflexes bilaterally. Relevant abnormalities on a CBC included the presence of an inflammatory leukogram with a left shift (segmented neutrophils 7.2 9 10/lL, reference interval [RI] 2.5– 12.5 9 10/lL; band neutrophils 2.2 9 10/lL, RI 0– 0.3 9 10/lL; lymphocytes 0.2 910/lL, RI 1.5–7 9 10/ lL) (Figure 1). Blood glucose was 68 mg/dL (RI 80– 115 mg/dL). The cat was placed in lateral recumbency with head elevation. It also received supplemental oxygen (oxygen cage 39%) and was warmed using a warm water bath (37°C). Symptomatic treatment included a crystalloid bolus of 0.9% sodium chloride (50 mL/kg IV), followed by 0.9% sodium chloride (21 mLs/h), valium (2.5 mg IV), dextrose 50% (3 mLs IV), mannitol (0.5 g/kg IV), and thiamine (250 mg SQ). Despite aggressive medical intervention, the cat suffered cardiac arrest. Although cardiopulmonary resuscitation was successful, the cat was unable to maintain a normal body temperature or ventilate unassisted, and the owner elected for humane euthanasia without necropsy. Upon extubation, the endotracheal tube contained a green frothy liquid. Figure 1. Blood smear from a cat. Wright–Giemsa,9 100 objective.

What Is Your Diagnosis? Eyelid mass in a dog

An 8-year-old spayed female Labrador Retriever was presented to the University of Florida College of Veterinary Medicine Ophthalmology Service (UFVH Ophthalmology) for evaluation of an approximately 10.5 9 10 9 9.5 mm diameter mass on the right lower eyelid. The mass had grown for an unknown duration but had increased in size over the previous month, according to the owner. Another smaller mass, measuring approximately 1–2 mm in diameter, was also noted on the lower eyelid margin and adjacent to the cornea. The dog was otherwise healthy with no other abnormalities noted on physical examination. The largest mass was sampled by fine-needle aspiration and submitted for cytologic evaluation (Figure 1A, B) prior to surgical removal of both masses for histopathologic assessment. (A)

Macrocytosis secondary to hydroxyurea therapy

A 10-year-old, male neutered Shetland Sheepdog was presented to the University of Florida for evaluation of a well-granulated mast cell tumor. Hydroxyurea therapy was instituted and serial CBCs showed persistent mild anemia and macrocytosis without a corresponding increase in polychromasia. The dogs MCV increased progressively, reaching its highest value of 100.0 fL after 6 months of treatment, and a diagnosis of macrocytosis associated with hydroxyurea therapy was made. The dogs increase in MCV was prominent, and rapidly decreased after the drug was discontinued, consistent with previous observations in human and canine subjects treated with hydroxyurea. Hydroxyurea is a cytotoxic chemotherapeutic agent used in a variety of conditions in human and veterinary medicine, and megaloblastic changes associated with its use have been described in multiple species. This report shows that hydroxyurea treatment is a differential diagnosis for prominent macrocytosis in dogs in the absence of other signs of erythrocyte regeneration.

Rhabdomyolysis and Artifactual Increase in Plasma Bicarbonate Concentration in an Amazon Parrot (Amazona species)

Abstract A 7-year-old male Amazon parrot housed outdoors presented with acute collapse, marked lethargy, and open-mouth breathing. The patient had stiffness of the pectoral muscles, and petechiation and ecchymosis noted around the eyes and beneath the mandible. Laboratory data revealed markedly increased aspartate aminotransferase, creatine kinase, and lactate dehydrogenase activity consistent with rhabdomyolysis, as well as markedly increased plasma bicarbonate concentration. Marked clinical improvement and resolution of laboratory abnormalities occurred with fluid therapy, administration of a nonsteroidal anti-inflammatory medication, and husbandry modifications, including indoor housing and dietary alteration. A spurious increase in bicarbonate measurement as documented in equine and bovine cases of rhabdomyolysis also occurred in this avian patient and must be considered for accurate interpretation of acid–base status in exotic species presenting with consistent clinical signs.

Antemortem Diagnosis of Coxiellosis in a Blue and Gold Macaw (Ara ararauna)

Abstract A 15-year-old female blue and gold macaw (Ara ararauna) was presented for evaluation after being found laterally recumbent, reluctant to move, and lethargic. Results of a complete blood count showed an increased number of immature heterophils with increased cytoplasmic basophilia and degranulation and the presence of a left shift. Radiographs and a computed tomography scan were performed and revealed a markedly enlarged spleen. An ultrasound-guided fine-needle aspirate of the spleen was submitted for cytologic examination and aerobic bacterial culture. While the culture revealed no growth, cytologic examination identified mononuclear phagocytes with cytoplasmic vacuoles containing structures consistent with bacteria. Pan-bacterial 16S rRNA polymerase chain reaction of the splenic sample followed by direct sequencing identified a Coxiella-like agent identical to one previously isolated in the liver of a golden-mantled rosella (Platycercus eximius). Phylogenetic analysis shows that avian coxiellosis agents and Coxiella burnetii, the agent of Q fever, represent 2 independent events of development of vertebrate pathogenicity in this group of tick endosymbionts. This report suggests diagnostic and treatment directions for coxiellosis in avian patients and indicates where further study is needed.

What is your diagnosis? Tracheobronchial lavage from a dog

A 4-month-old male castrated Labrador Retriever was referred to the Small Animal Internal Medicine Service at the Louisiana State University Veterinary Teaching Hospital and Clinic for a 3-week history of coughing with a terminal gag. The dog had a history of acute vomiting and fever 3 weeks prior. He had been treated with a short course of amoxicillin/ clavulanic acid (15 mg/kg orally twice daily) and metoclopramide (0.6 mg/kg orally twice daily) by his regular veterinarian, and no further vomiting episodes had occurred. He was housed with 5 other dogs at home and was otherwise healthy and up to date on routine vaccinations and heartworm prevention. On physical examination, bilaterally auscultated harsh lung sounds were the only abnormality. A CBC and serum biochemistry profile were unremarkable. On 3-view thoracic radiographs, a moderate bronchial pattern with an interstitial component was observed. Clinical differential diagnoses at that time included canine infectious respiratory disease complex (canine infectious tracheobronchitis) and bronchopulmonary parasitism. The dog was prescribed an additional course of antibiotics (amoxicillin/clavulanic acid 15 mg/ kg orally twice daily) to treat empirically for a bacterial pathogen prior to pursuing further diagnostics. At a 2-week recheck, there was improvement on thoracic radiographs; however, clinical signs had continued. A blind tracheobronchial lavage was performed for cytologic evaluation (Figure 1).

Mycobacterium Fortuitum Lipoid Pneumonia in a Dog

A 1-year old female spayed German Shepherd dog was evaluated for acute onset of dyspnea. Pyogranulomatous inflammation and green globoid structures were present on aspirates of the affected lung. Impression smears and histopathology confirmed pyogranulomatous pneumonia, with large amounts of lipid corresponding to the green structures noted cytologically, and identified poorly staining bacterial rods within lipid vacuoles. Special stains confirmed the presence of acid-fast bacterial rods, and polymerase chain reaction and DNA sequencing identified the organism as Mycobacterium fortuitum. M. fortuitum pneumonia is well described in humans and has previously been reported in 4 dogs and 1 cat. Lipid was a prominent cytologic and histologic feature, as is often described in humans and in the single feline case report. Additionally, this case highlights the variable cytologic appearance of lipid, as well as Mycobacterium spp, which are classically nonstaining with Wright-Giemsa.