Pseudoxanthomonas winnipegensis sp. nov., derived from human clinical materials and recovered from cystic fibrosis and other patient types in Canada, and emendation of Pseudoxanthomonas spadix Young et al. 2007.

Twelve isolates recovered from 10 cystic fibrosis/other patient types and a variety of clinical sources, were referred to Canada's National Microbiology Laboratory over 7 years. These were assignable to the genus Pseudoxanthomonas but were unidentifiable to species level. Patients included five males and five females from two geographically separated provinces, ranging in age from 2 months to 84 years. In contrast, most Pseudoxanthomonas species described to date have been derived from water, plants or contaminated soils. By 16S rRNA gene sequencing, the patient strains had ≥99.4 % similarity to each other but only 97.73-98.29 % to their closest relatives, Pseudoxanthomonas spadix or Pseudoxanthomonas helianthi. Bacteria were studied by whole genome sequencing using average nucleotide identity by Blastn, digital DNA-DNA hybridization, average amino acid identity, core genome and single nucleotide variant analyses, MALDI-TOF, biochemical and cellular fatty acid analyses, and by antimicrobial susceptibility testing. Bacterial structures were assessed using scanning and transmission electron microscopy. Strains were strict aerobes, yellowish-pigmented, oxidative, non-motile, Gram-stain-negative bacilli and generally unable to reduce nitrate. Strains were susceptible to most of the antibiotics tested; some resistance was observed towards carbapenems, several cephems and uniformly to nitrofurantoin. The single taxon group observed by 16S rRNA gene sequencing was supported by whole genome sequencing; genomes ranged in size from 4.36 to 4.73 Mb and had an average G+C content of 69.12 mol%. Based on this study we propose the name Pseudoxanthomonas winnipegensis sp. nov. for this cluster. Pseudoxanthomonas spadix DSM 18855T, acquired for this study, was found to be non-motile phenotypically and by electron microscopy; we therefore propose the emendation of Pseudoxanthomonas spadix Young et al. 2007 to document that observation.

Congenital nasal pyriform aperture stenosis: Analysis of twenty cases at a single institution.

OBJECTIVES: Congenital nasal pyriform aperture stenosis (CNPAS) is a rare cause of neonatal respiratory distress that is difficult to treat. The primary objective of this study was to identify factors that predict the need for initial and revision surgery for CNAPS. The secondary objective is to identify risk factors in maternal history associated with the development of CNPAS. METHODS: Infants with CNPAS between 2010 and 2017 were identified by ICD- 9 and 10 codes. Demographics, maternal history, anatomic features on imaging and medical and/or surgical management were reviewed. Frequencies, means and standard deviations were calculated. A p-value <.05 was considered significant. RESULTS: Twenty infants were included. All underwent flexible nasal endoscopy with inability to pass the scope in either nostril in 65% of infants. Nineteen had a CT scan and 13 had a MRI with midline defects in 76.3% and 53.8%, respectively. Solitary central mega-incisor was present in 65%. Half underwent surgical intervention at a mean age of 74.8 days, with 90% requiring revision surgery. There was no difference in pyriform aperture distance in the surgical and non-surgical patient subgroups (5.4 mm and 5.2 mm, p = .6 respectively). No specific variables were predictive of need for initial or revision surgery. Maternal diabetes mellitus (MDM) was found in 55% of mothers of infants with CNPAS. CONCLUSION: Pyriform aperture distance was not a predictor of surgical intervention. MRI should be considered in all infants with CNPAS as the rate of intracranial complications is high. MDM may be a risk factor for CNPAS.

Intracranial complications of acute sinusitis in children: The role of endoscopic sinus surgery.

OBJECTIVE: To study the role of endoscopic sinus surgery (ESS) in the management of intracranial complications of children with acute rhinosinusitis METHODS: Retrospective chart review at a tertiary care pediatric hospital MAIN OUTCOMES: Demographics, intracranial complications, length of hospital stay (LOS), neurological sequelae, ESS, neurosurgical procedures RESULTS: Twenty-four children with a mean age (SD) of 12.9 years (+/-3.2) with an intracranial complication(s) of acute rhinosinusitis were identified between 2005-2016. A total of 22 were included and 15 (68%) of these were males. The most common complications were: subdural abscess (n=10), epidural abscess (n=10), meningitis (n=5), intraparenchymal abscess (n=5), and cavernous sinus thrombosis (n= 2). Neurologic symptoms included headache (n=12), hemiparesis (n=5) and aphasia (n=3). Average length of stay was 16 (+/- 9.2) days. Average follow up was 7 (+/-5.6) months. One patient had residual seizures and 1 had recurrent rhinosinusitis. Aphasia and hemiparesis resolved in all patients within 1 year. Nineteen (86%) patients had ESS within 4 days of admission. Fourteen patients (63%) had a neurosurgical procedure, 6 (27%) required more than 1 neurosurgical procedure. Six patients (27%) had concurrent neurosurgical drainage and ESS. Four patients (17%) had neurosurgical procedure followed by ESS and 3 patients (13%) were treated only by a neurosurgical procedure. Patients who underwent ESS prior to a neurosurgical procedure had significantly less risk of needing a neurosurgical intervention (OR = .02, p < .01). There was a significantly higher proportion of neurosurgical patients with positive Strep anginosus cultures compared to the ESS only group (85.7% vs 37.5%, p = .02). Studies with larger patient populations are needed to determine the role of ESS in the management of intracranial complications of children with acute rhinosinusitis. DISCUSSION: Early ESS may be associated with less need for neurosurgical procedures.

How do filovirus filaments bend without breaking?

Viruses of the Mononegavirales have helical nucleocapsids containing a single-stranded negative-sense RNA genome complexed with the nucleoprotein and several other virus-encoded proteins. This RNA-protein complex acts as the template for replication and transcription during infection. Recent structural data has advanced our understanding of how these functions are achieved in filoviruses, which include dangerous pathogens such as Ebola virus. Polyploid filoviruses package multiple genome copies within strikingly long filamentous viral envelopes, which must be flexible to avoid breakage of the 19kb non-segmented genomic RNA. We review how the structure of filoviruses and paramyxoviruses permits this morphological flexibility in comparison to rhabdoviruses that have short, bullet-shaped virions with relatively rigid envelopes.

Conformational reorganization of the SARS coronavirus spike following receptor binding: implications for membrane fusion.

The SARS coronavirus (SARS-CoV) spike is the largest known viral spike molecule, and shares a similar function with all class 1 viral fusion proteins. Previous structural studies of membrane fusion proteins have largely used crystallography of static molecular fragments, in isolation of their transmembrane domains. In this study we have produced purified, irradiated SARS-CoV virions that retain their morphology, and are fusogenic in cell culture. We used cryo-electron microscopy and image processing to investigate conformational changes that occur in the entire spike of intact virions when they bind to the viral receptor, angiotensin-converting enzyme 2 (ACE2). We have shown that ACE2 binding results in structural changes that appear to be the initial step in viral membrane fusion, and precisely localized the receptor-binding and fusion core domains within the entire spike. Furthermore, our results show that receptor binding and subsequent membrane fusion are distinct steps, and that each spike can bind up to three ACE2 molecules. The SARS-CoV spike provides an ideal model system to study receptor binding and membrane fusion in the native state, employing cryo-electron microscopy and single-particle image analysis.

Architecture of the SARS coronavirus prefusion spike.

The emergence in 2003 of a new coronavirus (CoV) responsible for the atypical pneumonia termed severe acute respiratory syndrome (SARS) was a stark reminder that hitherto unknown viruses have the potential to cross species barriers to become new human pathogens. Here we describe the SARS-CoV 'spike' structure determined by single-particle cryo-EM, along with the docked atomic structures of the receptor-binding domain and prefusion core.

Intravenous antibiotic therapy for deep neck abscesses defined by computed tomography.

OBJECTIVE: To determine the effectiveness of using intravenous antibiotics alone to treat clinically stable children with clearly defined deep neck abscesses diagnosed by contrast-enhanced computed tomography (CT). DESIGN: Retrospective chart and CT scan review. SETTING: Tertiary care children's hospital. PATIENTS: The study comprised clinically stable pediatric patients who presented with signs and symptoms of a deep neck infection and who had CT scans demonstrating an abscess in the parapharyngeal space, retropharyngeal space, or both that included (1) a well-formed ring enhancement around a nonenhancing density consistent with fluid and (2) a size greater than 1 cm in every dimension. MAIN OUTCOME MEASURES: Clinical resolution of the signs and symptoms of the deep neck abscess after treatment with intravenous antibiotics. RESULTS: Over a 22-month period (May 1999 to March 2001), 11 children ranging in age from 4 months to 16(1/2) years who had contrast-enhanced CT evidence of deep neck abscess and no clinical evidence of severe symptoms or significant airway compromise were initially treated with intravenous antibiotics. Ten (91%) of the 11 children responded to intravenous antibiotic therapy as their only treatment. All 10 responders began to improve clinically by 48 hours. The symptoms resolved in 5 children by treatment day 3. Five to 8 days of treatment were required to completely resolve the symptoms in the other 5 patients. The 1 child who did not respond to intravenous antibiotic therapy underwent surgical drainage of her deep neck abscess within 12 hours of admission, with purulence discovered at the time of surgery. CONCLUSION: In a select number of clinically stable children, deep neck abscesses diagnosed on contrast-enhanced CT scans using strict radiographic criteria can be effectively treated with intravenous antibiotics alone.