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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently a global pandemic with unprecedented public health, economic and social impact. The development of effective mitigation strategies, therapeutics and vaccines relies on detailed genomic and biological characterization of the regional viruses. This study was carried out to isolate SARS-CoV-2 viruses circulating in Anatolia, and to investigate virus propagation in frequently-used cells and experimental animals. We obtained two SARS-CoV-2 viruses from nasopharngeal swabs of confirmed cases in Vero E6 cells, visualized the virions using atomic force and scanning electron microscopy and determined size distribution of the particles. Viral cytopathic effects on Vero E6 cells were initially observed at 72 h post-inoculation and reached 90% of the cells on the 5th day. The isolates displayed with similar infectivity titers, time course and infectious progeny yields. Genome sequencing revealed the viruses to be well-conserved, with less than 1% diversity compared to the prototype virus. The analysis of the viral genomes, along with the available 62 complete genomes from Anatolia, showed limited diversity (up to 0.2% on deduced amino acids) and no evidence of recombination. The most prominent sequence variation was observed on the spike protein, resulting in the substitution D614G, with a prevalence of 56.2%. The isolates produced non-fatal infection in the transgenic type I interferon knockout (IFNAR−/-) mice, with varying neutralizing antibody titers. Hyperemia, regional consolidation and subpleural air accumulation was observed on necropsy, with similar histopathological and immunohistochemistry findings in the lungs, heart, stomach, intestines, liver, spleen and kidneys. Peak viral loads were detected in the lungs, with virus RNA present in the kidneys, jejunum, liver, spleen and heart. In conclusion, we characterized two local isolates, investigated in vitro growth dynamics in Vero E6 cells and identified IFNAR−/− mice as a potential animal model for SARS-CoV-2 experiments.

Xanthogranulomatous inflammation is common in interval appendectomy specimens in adults, but it is unusual in children. Histopathologic specimens of interval appendectomy, within an 8-year period, were reevaluated to assess the true incidence. A computer search of the hospital database of all appendectomies was performed between January 2008 and June 2015 to identify all interval appendectomy cases. A total of 2694 patients underwent appendectomies. Of these, 13 were interval appendectomies. After pathologic evaluation, 2 (15.4%) of the specimens were reported as xanthogranulomatous appendicitis (XA). Histopathologic examination of these interval appendectomy specimens, granulomas (59%), xanthogranulomatous inflammation (36%) and Crohn-like changes (50%) were common in adults. However, XA is a particularly rare clinical entity among children. Two cases of XA were reported in children in the English literature. One was a 12-year old boy that underwent interval appendectomy 6 weeks after an episode of acute appendicitis. The other was an 11-year old boy with acute (non-interval) appendicitis, but the complete blood count was suggestive of an acute suppurative inflammation. These two cases are the 3rd and 4th cases of XA reported in children in the English literature, and both were managed by interval appendectomy. Thus, XA may be encountered in interval appendectomy specimens and association with IBD has to be ruled out.