Development of duplex qPCR targeting Carnobacterium maltaromaticum and Vagococcus salmoninarum.

In November 2018, Vagococcus salmoninarum was identified as the causative agent of a chronic coldwater streptococcosis epizootic in broodstock brook trout (Salvelinus fontinalis) at the Iron River National Fish Hatchery in Wisconsin, USA. By February 2019, the epizootic spread to adjacent raceways containing broodstock lake trout (Salvelinus namaycush), whereby fish were found to be coinfected with Carnobacterium maltaromaticum and V. salmoninarum. To differentiate these two pathogens and determine the primary cause of the lake trout morbidity, a quantitative real-time PCR (qPCR) was developed targeting the C. maltaromaticum phenylalanyl-tRNA synthase alpha subunit (pheS) gene. The qPCR was combined with a V. salmoninarum qPCR, creating a duplex qPCR assay that simultaneously quantitates C. maltaromaticum and V. salmoninarum concentrations in individual lake trout tissues, and screens presumptive isolates from hatchery inspections and wild fish from national fish hatchery source waters throughout the Great Lakes basin. Vagococcus salmoninarum and C. maltaromaticum were co-detected in broodstock brook trout from two tribal hatcheries and C. maltaromaticum was present in wild fish in source waters of several national fish hatcheries. This study provides a powerful new tool to differentiate and diagnose two emerging Gram-positive bacterial pathogens.

Vagococcus salmoninarum II-qPCR, tropism and egg-associated transmission.

Vagococcus salmoninarum was identified as the causative agent of a chronic epizootic in broodstock "coaster" brook trout (Salvelinus fontinalis) at the Iron River National Fish Hatchery. The epizootic spanned more than a year, was unresponsive to multiple florfenicol treatments, and resulted in >50% mortality of the affected fish. The decision was made to cull the remaining fish during spawning, which presented an opportunity to more thoroughly examine V. salmoninarum sampling methods, organ tropism and vertical transmission. A newly developed qPCR targeting the pheS gene was used in concert with bacterial culture to show that V. salmoninarum indeed disproportionately affects females and has a tropism for female reproductive tissues. The study demonstrates that some female reproductive tissues (e.g. ovarian fluid, unfertilized eggs) are also an effective option for non-lethal detection. Despite the widespread presence of V. salmoninarum in ovarian fluid and on egg surfaces, we found no evidence of intra-ova transmission.

Vagococcus salmoninarum I-A chronic coldwater streptococcosis in broodstock brook trout (Salvelinus fontinalis) in Wisconsin, USA.

In 2018, Vagococcus salmoninarum was isolated from two lots of broodstock "coaster" brook trout (Salvelinus fontinalis) containing ~1,500 fish at the Iron River National Fish Hatchery, at which time it was identified as the causative agent of a chronic coldwater streptococcosis epizootic. Clinical signs included exophthalmia, lethargy, erratic swimming and loss of equilibrium. Female fish experienced disproportionately higher morbidity and mortality than male co-inhabitants, and routinely retained eggs following spawning. The most consistent gross clinical sign was heart pallor and turbid pericardial effusion. An attempted treatment using florfenicol was ineffective at halting the epizootic, which spanned more than a year and resulted in >50% mortality before remaining fish were culled. As there is no previous documentation of V. salmoninarum at this hatchery or in this species, it is still unclear what circumstances led to this epizootic. The inability to treat this chronic disease led to the loss of valuable broodstock, hampering ongoing fishery conservation efforts in the Great Lakes Basin.

Eligibility for dapagliflozin in unselected patients hospitalised with decompensated heart failure.

Patients with heart failure with reduced ejection fraction (HFrEF) who received the sodium-glucose co-transport 2 inhibitor, dapagliflozin, in the DAPA-HF (Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure) study have a significant reduction in worsening heart failure (HF) and cardiovascular death. It is uncertain what proportion of patients admitted to a large regional cardiac centre with decompensated heart failure would be eligible for dapagliflozin post-discharge based on their characteristics at discharge. The DAPA-HF study criteria were retrospectively applied to a cohort of 521 consecutive patients referred to the inpatient HF service in a tertiary cardiac centre in South West Wales between April 2017 and April 2018. Inclusion criteria: left ventricular ejection fraction (LVEF) < 40%, New York Heart Association (NYHA) class II-IV symptoms and an elevated N-terminal pro-B-type naturietic peptide (NT-proBNP). Exclusion criteria: systolic blood pressure (SBP) < 95 mmHg, estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73 m2 or type 1 diabetes mellitus. We did not have complete NTproBNP data for the cohort, as it was not routinely measured at the time in our institute. There were 478 patients, mean age 78 ± 13 years, 57% male and 91% NYHA class II-IV symptoms, were included in the analysis. Of these, 247 patients had HFrEF, 219 (46%) patients met the inclusion criteria, 231 (48%) were excluded as LVEF was > 40%, and 48 (10%) were excluded with NYHA class I symptoms. Of the 219 patients who met the inclusion criteria, 13 (5.9%) had a SBP < 95 mmHg, 48 (22%) had eGFR < 30 ml/min/1.73 m2, leaving 136 (28.5% of total and 55% of those with HFrEF) who met DAPA-HF study criteria. In our study, 28.5% of all heart failure admissions and 55% of patients with HFrEF would be eligible for dapagliflozin post-discharge according to the DAPA-HF study entry criteria.

Prevalence and significance of T-wave inversions in predominantly Caucasian adolescent athletes.

AIMS: Athletic activity is associated with electrocardiographic T-wave inversions in some adults, resembling those observed in cardiomyopathy. The prevalence and significance of T-wave inversions in adolescent athletes, the group most vulnerable to exercise-related sudden death from cardiomyopathy, is unknown. METHODS AND RESULTS: This study evaluated 1710 adolescent athletes and 400 healthy controls. Subjects with T-wave inversions underwent intensive cardiac investigations to identify a potential cause. There was no significant difference in the overall prevalence of T-wave inversions between athletes and controls (4 vs. 3%; P = 0.46). T-wave inversions in leads V1-V3 were largely confined to athletes and controls aged <16 years. Only 0.1% of athletes aged >or=16 years exhibited T-wave inversions beyond V2. T-wave inversions in the inferior and/or lateral leads and deep T-wave inversions occurred infrequently in athletes (1.5 and 0.8%, respectively) and were associated with a high prevalence of left ventricular hypertrophy or congenital cardiac anomalies. Despite intensive investigations, no athlete was diagnosed with a cardiomyopathy. CONCLUSIONS: T-wave inversions in V1-V3 are relatively common in athletes <16 years and probably represent the juvenile electrocardiogram pattern. In adolescent athletes, T-wave inversions beyond V2 if >or=16 years, T-wave inversions in the inferior/lateral leads and deep T-wave inversions in any lead are unusual, warranting further investigations for underlying cardiomyopathy.