Genome-based Reclassification of Paraburkholderia insulsa as a Later Heterotypic Synonym of Paraburkholderia fungorum and Proposal of Paraburkholderia terrae subsp. terrae subsp. nov. and Paraburkholderia terrae subsp. steynii subsp. nov.

Based on the 16S rRNA gene sequences similarity of > 99.8%, the phylogeny of 88 Paraburkholderia strains was reconstructed. Further, they were subjected to overall genome-related indices (OGRI), which resulted in the identification of distinct pairs of species that were closely related. A pair consist of the type strains of Paraburkholderia insulsa and Paraburkholderia fungorum possessed a dDDH value of 87.9%, correspondingly, and the average nucleotide identity (ANI) value was 98.5%. Based on the phylogenetic analysis, OGRI and phenotypical evidence, P. insulsa was proposed as a later heterotypic synonym of P. fungorum. Furthermore, a pair comprising type strains of Paraburkholderia terrae and Paraburkholderia steynii possessed dDDH and ANI values of 71.2% and 96.6%, respectively, and difference in phenotypic traits, which supports a subspecies proposal within these taxa. Thus, the recently described Paraburkholderia steynii was proposed into two subspecies namely Paraburkholderia terrae subsp terrae subsp. nov and as Paraburkholderia terrae subsp. steynii subsp. nov.

Radiation Dose and Image Quality in Pediatric Cardiac Computed Tomography: A Comparison Between Sequential and Third-Generation Dual-Source High-Pitch Spiral Techniques.

The aim of this study was to investigate whether there is a reduction in radiation dose and improvement in image quality of pediatric cardiac computed tomography scans performed using the high-pitch spiral technique on a new third-generation dual-source 2 × 192-slice scanner (group B) compared with scans performed using the sequential technique on a single-source 256-slice scanner (group A). We performed a retrospective observational study on 40 patients aged ≤18 years who underwent prospectively electrocardiogram-triggered cardiac computed tomography. Image quality was assessed by pre-defined objective indices and a four-point subjective score. Apart from a higher mean heart rate in group A (P = 0.016), there were otherwise no significant inter-group differences in patient characteristics. The median effective dose was 4.41 mSv (interquartile range 2.58-5.90 mSv) in group A and 0.52 mSv (interquartile range 0.39-0.59 mSv) in group B (P < 0.001), representing a 88 % reduction. Subjective image quality score was significantly better in group B (4 = excellent with no artifact, mode 57.1 %) than in group A (3 = good with mild artifact, mode 57.9 %) (P < 0.001). Noise index, signal-to-noise ratio and contrast-to-noise ratio between both groups were not statistically significant. New third-generation dual-source high-pitch spiral scan technique can deliver excellent image quality with low radiation dose. Our results suggest that it should be considered as a first-choice technique for performing cardiac computed tomography in the pediatric population.

Late complications following tetralogy of Fallot repair: the need for long-term follow-up

<p><b>INTRODUCTION</b>We report a series of operated tetralogy of Fallot (TOF) patients focusing on complications and outcomes.</p><p><b>MATERIALS AND METHODS</b>Data from TOF patients seen at our centre's adult congenital heart disease clinic was analysed.</p><p><b>RESULTS</b>There were 21 patients: the mean age was 32.2 +/- 12.4 years; the age at first operation was 9.0 +/- 7.9 years; the mean postoperative follow-up duration was 23.5 +/- 12.1 years; and the current New York Heart Association (NYHA) status: I, 82%; II, 4%; III, 14%. Fourteen patients had complete operative notes. All these patients underwent total TOF correction; 2 had staged aortopulmonary shunt with total correction at a mean of 3.2 years later, pulmonary artery patch augmentation in 8 patients and pulmonary valvotomy in 8 patients. Three patients required pulmonary valve homograft replacement for severe pulmonary regurgitation (PR) at 13, 28 and 36 years after the initial corrective operation.</p><p><b>CURRENT INVESTIGATIONS</b>RBBB on ECG (91%), QRS duration 137 +/- 29 ms. Echocardiography showed dilated right ventricular end-diastolic (RVED) diameters (3.2 +/- 0.8 cm); severe PR (67%), residual right ventricular outflow tract obstruction (RVOTO) (42%) and VSD patch leakage (9%). Cardiac magnetic resonance (CMR) (8 patients) showed dilated RVED volumes 252.6 +/- 93.8 mL, indexed RV volume 165.7 +/- 34.8 mL; RV systolic function was preserved in most patients with a RV ejection fraction of 49.5 +/- 5.7%. One patient had atrial tachycardia and another had frequent non-sustained ventricular tachycardia that required radiofrequency ablation.</p><p><b>CONCLUSION</b>Patients with TOF who had full corrective surgery during childhood are now surviving into adulthood. Many challenges arising from complications in the postoperative period remain. It is imperative that adult TOF patients should have regular followup to monitor development and subsequent management of these complications.</p>