Phylogroup and lpfA influence epithelial invasion by mastitis associated Escherichia coli

Escherichia coli infection is one of the most common causes of bovine mastitis in well managed dairies. Although E. coli infections are usually transient, E. coli can also cause persistent intramammary infections. We sought to determine whether E. coli isolates recovered from either transient or persistent intramammary infections differed both genetically and in their ability to invade mammary epithelial cells. E. coli isolates from transient (EC(trans), n=16) and persistent (EC(pers), n=12) mastitis cases were compared for differences in overall genotype, virulence genes, serotype, phylogroup (A, B1, B2, D), and invasion of bovine mammary epithelial cells, MAC-T by microarray analysis, suppressive subtractive hybridization, PCR and gentamicin protection assays. EC(trans) and EC(pers) were diverse in overall genotype and serotype, and were predominantly of phylogroups A and B1. Both EC(trans) and EC(pers) contained genes encoding type II, IV and VI secretion systems, long polar fimbriae (lpfA) and iron acquisition, and lacked genes associated with virulence in diarrheagenic E. coli. EC(trans) had fewer virulence genes than EC(pers) (p<0.05), but no individual virulence genes were unique to either group. In phylogroup A, EC(pers) were more invasive than EC(trans) (p<0.05), but no difference was observed between them in phylogroup B1. Enhanced epithelial cell invasion was associated with lpfA (p<0.05). Our findings indicate that a genetically diverse group of E. coli is associated with transient and persistent mastitis. We did not identify a set of bacterial genes to account for phenotypic differences. However, we found that mastitis phenotype, phylogroup and presence of lpfA were associated with the ability to invade cultured bovine mammary epithelial cells.     

Diagnosis and management of cor triatriatum dexter in a Pyrenean mountain dog and an Akita Inu

Cor Triatriatum Dexter is a rare, congenital cardiac defect in which the right atrium is partitioned into two compartments, effectively creating a triatrial heart. The clinical signs exhibited by the patient usually relate to impeded venous return via the caudal vena cava. The two dogs in this report both displayed ascites from a young age and grew poorly. In both cases the diagnosis was made during echocardiographic examination and was confirmed by angiography. Both dogs were successfully treated by resection of the partitioning membrane within the right atrium, using hypothermia and inflow occlusion to achieve a clear surgical field. Both dogs recovered well, their clinical signs resolved and they have grown to normal adult size.     

Dynamic right ventricular outflow obstruction: a new cause of systolic murmurs in cats

We have identified and characterized a new cause of variable parasternal systolic murmurs in cats. Color Doppler echocardiography of 51 cats presented for evaluation of a cardiac murmur demonstrated a localized, turbulent systolic jet located within the right ventricular (RV) outflow region, originating just cranial to the tricuspid valve. Spectral Doppler tracings of the turbulent jets showed abnormally high peak velocity, late systolic flow acceleration, and marked variability with heart rate, typical of dynamic stenosis. Frame-by-frame examination of 2-dimensional (2D) echocardiographic images after color Doppler subtraction revealed systolic apposition of the RV free wall with the interventricular septum at the origin of the turbulent jets. Therefore, we termed this turbulent flow pattern "dynamic right ventricular obstruction" (DRVO). Most cats with DRVO were >4 years old (45 of 51, 88%) and initially presented with concurrent noncardiac disease (73%). Noncardiac diseases associated with DRVO in older cats included high cardiac output states (hyperthyroidism, anemia, and inflammatory disease) and chronic renal failure with and without systemic hypertension. Of the 45 cats >4 years old, 4 (9%) had no evidence of any other cardiac or noncardiac disease. In contrast, 5 of 6 cats (83%) <4 years old had concurrent cardiac disease. No breed predisposition was identified. Follow-up examination of 10 cats demonstrated no change in the disorder in 8 cats but revealed the disappearance of the murmur and abnormal RV Doppler flow signal in 2 cats after renal transplantation. We propose that DRVO is a physiologic cause of systolic murmurs in cats attributable to RV systolic narrowing.     

Right ventricular outflow tract fractional shortening: an echocardiographic index of right ventricular systolic function in dogs with pulmonary hypertension

Objectives

To create reference intervals for right ventricular outflow tract fractional shortening (RVOT-FS) in healthy dogs and examine diagnostic performance of this index in dogs with pulmonary hypertension (PH). In addition, we examine the impact of myxomatous mitral valve disease (MMVD) without PH on RVOT-FS.

Tricuspid annular plane systolic excursion-to-aortic ratio provides a bodyweight-independent measure of right ventricular systolic function in dogs

Objectives

To evaluate whether tricuspid annular plane systolic excursion (TAPSE) can be normalized to aortic valve (Ao) measurements in dogs. To determine TAPSE:Ao reference intervals for healthy dogs and examine diagnostic performance of TAPSE:Ao in dogs with pulmonary hypertension (PH).

Murmur grading in humans and animals: past and present

Cardiac murmurs were first described approximately 200 years ago. Subsequently, various clinicians, starting with Samuel Levine, have proposed grading schemes, depicting intensity, or other murmur characteristics, in an attempt to differentiate pathological and physiological murmurs or different degrees of pathology. In the 1960s, these schemes were adapted by veterinary cardiologists and have been used over the last 50 years. However, the clinical utility of these schemes has only recently been examined in veterinary medicine (and never examined in humans), and these studies suggest that the current, commonly used murmur grading scheme is unnecessarily complex and contains redundant information. A simpler, more intuitive grading scheme might achieve the same desired outcome as the more complex scheme, potentially with less confusion. This review examines the history of murmur grading and proposes a reconsideration of the current grading scheme to improve clinical communication.