The role of Acinetobacter baumannii as a nosocomial pathogen for dogs and cats in an intensive care unit

Acinetobacter baumannii is a nosocomial pathogen associated with high morbidity and mortality in humans. Whereas infections with strains of Acinetobacter species have been reported in various situations, the importance of A baumannii as a nosocomial pathogen in veterinary hospitals has not been studied so far. In this retrospective case series, we describe 17 dogs and 2 cats from which A baumannii had been isolated during a 21/2-year period. In 7 dogs, A baumannii induced systemic signs of illness, whereas 12 animals showed signs of local infection. In all animals with systemic infection, and in 2 with localized infection, A baumannii contributed to the death of the animal or contributed to euthanasia; the remaining 8 dogs and both cats recovered. Molecular typing of the isolates with restriction polymorphisms of ribosomal DNA provided evidence of nosocomial spread of this pathogen and for the presence of several strains of A baumannii in the hospital environment.     

Surgical repair of a mandibular degloving injury in a 5‐month‐old colt

A 5‐month‐old colt sustained a mandibular degloving injury and penetrating cheek wound after catching his cheek on a metal hook. Avulsion of the lower left lip and cheek exposed parts of the underlying labial surface, interalveolar margin and body of the mandible. The injury prevented the colt from closing his mouth completely and food accumulated between the degloved mandible and avulsed soft tissues. Surgical repair included 7 stented, transmandibular mattress sutures placed over the length of the interalveolar margin, closing the dead space and repositioning the avulsed soft tissues. The horse recovered without complications and functional as well as cosmetic outcome were excellent.     

Lameness caused by plate‐like osteoma cutis in a Thoroughbred colt

This report describes a case of osteoma cutis diagnosed by physical examination, surgery and histopathological examination. A 2‐year‐old Thoroughbred colt with hindlimb lameness was brought to our facility. Physical examination showed a well‐circumscribed, large plate‐like mass covered with normal haired skin in the right thigh region. Ultrasonography revealed a subcutaneous linear mass. After surgical removal, histopathological examination showed thin mature bone surrounded by fibrocollagenous tissues. To the authors' knowledge, this is the first report of spontaneous idiopathic osteoma cutis in horses.     

Nonsteroidal anti‐inflammatory drug associated right dorsal colitis in the horse

Right dorsal colitis in horses is a disease characterised by mucosal ulceration and oedema that is localised to the right dorsal colon. It is considered one of the more severe adverse effects associated with the use of nonsteroidal anti‐inflammatory drugs (NSAIDs), particularly phenylbutazone. Diagnosis is typically made based on a history of NSAID administration, the presence of hypoproteinaemia and hypoalbuminaemia, as well as ultrasound evidence of thickening and oedema of the right dorsal colon wall. Definitive diagnosis is made at surgery or necropsy. Treatment involves discontinuation of NSAID therapy, dietary management, and mucosal protectants such as misoprostol and sucralfate. Prognosis is dependent upon early recognition and appropriate treatment. Horses on prolonged courses of NSAIDs should have frequent monitoring of serum total protein and albumin concentrations, as this is one of the earliest and most consistent clinicopathological findings.     

Mitral valve and tricuspid valve dysplasia in a 9‐week‐old Standardbred colt

A 9‐week‐old Standardbred colt was presented for investigation of dull demeanour, exercise intolerance and heart murmurs. Cardiac auscultation revealed a grade 5/6 holosystolic murmur and a grade 5/6 pansystolic murmur over the left and right cardiac apex respectively, and an irregularly irregular cardiac rhythm. Electrocardiographic examination findings were consistent with atrial fibrillation and tachycardia. Echocardiographic examination identified marked atrioventricular regurgitation and atrial dilation bilaterally, thickening of the mitral and tricuspid valves and dilation of the pulmonary artery consistent with pulmonary hypertension. No ventricular or atrial septal defect was present. Cardiomegaly and diffuse pulmonary oedema were evident on examination of lateral thoracic radiographs. Dysplasia of the mitral and tricuspid valves, eccentric cardiomegaly and pulmonary oedema were confirmed by post mortem examination. Dysplasia of the atrioventricular valves represents a rare cause of biventricular failure in the horse.     

Experimental reactivation of equine herpesvirus‐3 following corticosteroid treatment

State of latency, well known for several herpesviruses, has been proposed for equine herpesvirus‐3 (EHV‐3) and supported by epidemiological observations. No detailed assessment about reactivation, patterns of excretion and re‐excretion has been formally reported. An experimental reactivation study by corticosteroid treatment in previously naturally infected horses was therefore carried out. Two polo mares with clinical and virologically confirmed history of equine coital exanthema were injected with dexamethasone and prednisolone on 3 successive days. Clinical signs, body temperature and clinical samples for virological and serological studies were obtained daily. Mares did not show any systemic clinical signs or hyperthermia. EHV‐3 shedding, seroconversion and the presence of a small lesion were observed in one of the mares under study 2 weeks after corticosteroid treatment. The results demonstrate that this virus exhibits a latency‐reactivation behaviour similar to that of other alpha herpesviruses. Reactivation of latency may have an important bearing on the appearance of clinical signs in mares and/or stallions during the breeding season without the actual evidence of transfer from mare to stallion or vice versa.     

Identification of drug‐resistant subpopulations in canine hemangiosarcoma

Canine hemangiosarcoma is a rapidly progressive disease that is poorly responsive to conventional chemotherapy. Despite numerous attempts to advance treatment options and improve outcomes, drug resistance remains a hurdle to successful therapy. To address this problem, we used recently characterized progenitor cell populations derived from canine hemangiosarcoma cell lines and grown as non‐adherent spheres to identify potential drug resistance mechanisms as well as drug‐resistant cell populations. Cells from sphere‐forming cultures displayed enhanced resistance to chemotherapy drugs, expansion of dye‐excluding side populations and altered ATP‐binding cassette (ABC) transporter expression. Invasion studies demonstrated variability between cell lines as well as between sphere and monolayer cell populations. Collectively, our results suggest that sphere cell populations contain distinct subpopulations of drug‐resistant cells that utilize multiple mechanisms to evade cytotoxic drugs. Our approach represents a new tool for the study of drug resistance in hemangiosarcoma, which could alter approaches for treating this disease.     

Methicillin‐resistant Staphylococcus aureus in Resident Animals of a Long‐term Care Facility

Animals provide benefits to elderly and chronically ill people by decreasing loneliness, increasing social interactions, and improving mental health. As a result, many hospitals and long‐term care facilities allow family pets to visit ill or convalescing patients or support animal‐assisted therapy programs. These include programs that have resident animals in long‐term care facilities. Despite the benefits, there are concerns about disease transmission between pets and patients. Antibiotic‐resistant bacteria, such as methicillin‐resistant Staphylococcus aureus (MRSA), are a recognized problem in healthcare settings leading to refractory infections and potentially life‐threatening illnesses. MRSA has been isolated from numerous animal species, yet few studies are available on the carriage of this pathogen in animals residing in long‐term care facilities. Our objective was to characterize MRSA carriage among resident animals in a long‐term care facility. Methods: To document MRSA colonization, nasal swabs from 12 resident animals (one dogs and 11 cats) of a long‐term care facility were collected weekly for 8 weeks. Staphylococcus isolates were characterized by antimicrobial susceptibility and MRSA isolates were further characterized by pulsed‐field gel electrophoresis (PFGE). PFGE isolate patterns were compared with an existing database of MRSA isolate patterns at the Minnesota Department of Health. Results: Two of 11 cats were colonized with MRSA. MRSA was recovered from five of eight weekly samples in one cat and two of eight weekly samples in the other cat. All isolates were classified as USA100 (healthcare‐associated strains). Discussion: Long‐term care resident animals may acquire MRSA. Clonally related strains were identified over the 8‐week sampling period. It is unclear if pets serve as an on‐going source of infection to their human companions in long‐term care facilities.     

Antimicrobial activity of a bovine myeloid antimicrobial peptide (BMAP‐28) against methicillin‐susceptible and methicillin‐resistant Staphylococcus aureus

A bovine myeloid antimicrobial peptide (BMAP‐28) is a member of the cathelicidin family which is included in the innate immune system of mammals. Recently, there have been many studies about antimicrobial peptides. This study aims to clarify whether BMAP‐28 has bactericidal activity against methicillin‐resistant Staphylococcus aureus (MRSA) and compares its activity against methicillin‐susceptible S. aureus (MSSA) and MRSA. We found that the peptide was effective in killing MRSA (minimal inhibitory concentration (MIC) range; 5–20 µg/mL). It was also revealed that MSSA (MIC range; 1.25–20 µg/mL) had two levels of susceptibility to BMAP‐28. We also examined the effect of BMAP‐28 on bacterial shape to visually show its activity. After exposure to the peptide, both MSSA and MRSA cells showed the morphological changes on their surfaces. Our results indicate that BMAP‐28 is a promising candidate for medicine against drug‐resistant bacteria.     

Haemoabdomen and colitis following a colon displacement in a 9‐year‐old Thoroughbred mare

This report describes acute haemoabdomen following phenylephrine administration in a case treated for left dorsal displacement of the large colon. The horse also subsequently developed a severe colitis which was treated with aggressive medical therapy.     

Aortic rupture causing cardiac tamponade in a 24‐day‐old Friesian colt with concurrent colonic Chlamydiosis and Balantidiasis

A 24‐day‐old Friesian colt died suddenly and a physical examination the morning the foal died showed no abnormalities and serum IgG levels >8.0 g/l. Necropsy examination revealed haemopericardium and a 2 cm transverse tear at the root of the aorta. The foal was also found to have Chlamydophila spp. in the epithelium and Balantidium coli on the mucosal surface of the large colon. An aortic rupture is a novel finding in a foal, colonic Chlamydiosis has not been previously reported in horses and Balantidium coli has not been reported in equids in North America.     

Haemolytic anaemia as a complication following colic surgery in a 10‐year‐old Arabian stallion

Immune‐mediated haemolytic anaemia is rare in the horse. This case report discusses the clinical presentation and treatment of this condition in an Arabian stallion following abdominal surgery for large colon volvulus. On Day 10 of hospitalisation the stallion's PCV dropped by 10% whilst his total solids remained stable, consistent with haemolytic anaemia. The stallion was treated with whole blood transfusions and dexamethasone and recovered to be discharged on Day 42. This is an interesting example of immune mediated haemolytic anaemia associated with a complicated gastrointestinal condition. It demonstrates the wide variety of potential aetiologies underlying a haemolytic episode and the necessity for expedient treatment.     

Measurement of C‐peptide concentrations and responses to somatostatin,glucose infusion,and insulin resistance in horses

Reasons for performing study: Hyperinsulinaemia is detected in horses with insulin resistance (IR) and has previously been attributed to increased pancreatic insulin secretion. Connecting peptide (C‐peptide) can be measured to assess pancreatic function because it is secreted in equimolar amounts with insulin and does not undergo hepatic clearance. Hypothesis: A human double antibody radioimmunoassay (RIA) detects C‐peptide in equine serum and concentrations would reflect responses to different stimuli and conditions. Methods: A validation procedure was performed to assess the RIA. Six mature mares were selected and somatostatin administered i.v. as a primed continuous rate infusion, followed by 50 nmol human C‐peptide i.v. Insulin and C‐peptide concentrations were measured in horses (n = 6) undergoing an insulin‐modified frequently sampled i.v. glucose tolerance test, and in horses with insulin resistance (n = 10) or normal insulin sensitivity (n = 20). Results: A human RIA was validated for use with equine sera. Endogenous C‐peptide secretion was suppressed by somatostatin and median (range) clearance rate was 0.83 (0.15–1.61) ml/min/kg bwt. Mean ± s.d. C‐peptide‐to‐insulin ratio significantly (P = 0.004) decreased during the glucose tolerance test from 3.60 ± 1.95 prior to infusion to 1.03 ± 0.18 during the first 20 min following dextrose administration. Median C‐peptide and insulin concentrations were 1.5‐ and 9.5‐fold higher, respectively in horses with IR, compared with healthy horses. Conclusions: Endogenous C‐peptide secretion decreases in response to somatostatin and increases after dextrose infusion. Results suggest that relative insulin clearance decreases as pancreatic secretion increases in response to dextrose infusion. Hyperinsulinaemia in insulin resistant horses may be associated with both increased insulin secretion and decreased insulin clearance. Potential relevance: Both C‐peptide and insulin concentrations should be measured to assess pancreatic secretion and insulin clearance in horses.     

Surgical treatment of a rostral mandibular complex odontoma in a 3‐year‐old horse

Complex odontomas are rare odontogenic tumours in horses comprised of a combination of mesenchymal and epithelial tissues. Examination, radiographic and histopathological findings in this patient all represent the typical behaviour of a complex odontoma. Oral tumours in horses may have treatment limitations due to tumour size and location. Similar to treatment in other species, surgical enucleation was curative for this type of tumour.