The initial cases of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) occurred in Wuhan, China, in December 2019 and swept the world by 23 June 2020 with 8 993 659 active cases, 469 587 deaths across 216 countries, areas or territories. This strongly implies global transmission occurred before the lockdown of China. However, the initial source's transmission routes of SARS‐CoV‐2 remain obscure and controversial. Research data suggest bat (RaTG13) and pangolin carried CoV were the proximal source of SARS‐CoV‐2. In this study, we used systematic phylogenetic analysis of Coronavirinae subfamily along with wild type human SARS‐CoV, MERS‐CoV, and SARS‐CoV‐2 strains. The key residues of the receptor‐binding domain (RBD) and O‐linked glycan were compared. SARS‐CoV‐2 strains were clustered with RaTG13 (97.41% identity), Pangolin‐CoV (92.22% identity) and Bat‐SL‐CoV (80.36% identity), forms a new clade‐2 in lineage B of beta‐CoV. The alignments of RBD contact residues to ACE2 justified? Those SARS‐CoV‐2 strains sequences were 100% identical by each other, significantly varied in RaTG13 and pangolin‐CoV. SARS‐CoV‐2 has a polybasic cleavage site with an inserted sequence of PRRA compared to RaTG13 and only PRR to pangolin. Only serine (Ser) in pangolin and both threonine (Thr) and serine (Ser) O‐linked glycans were seen in RaTG13, suggesting that a detailed study needed in pangolin ( Manis javanica ) and bat ( Rhinolophus affinis ) related CoV.

Linezolid therapy is known to cause black hairy tongue, which is benign and reversible. A 65‐year‐old diabetic male was on treatment for diabetic nonhealing ulcer involving right foot and sole for the past 6 months. Linezolid was started based on the culture and sensitivity of the pus. Patient developed thrombocytopenia and black hairy tongue after 7 days of the drug regimen. Drug was stopped and patient was advised to maintain good oral hygiene, soft tooth brush for brushing and regular mouth wash with lukewarm water. The black hairy tongue completely resolved within a week after stopping the drug. The taste and foreign body sensation on the tongue while swallowing were also improved. The diabetic wound was treated by starting vancomycin after giving a surgical wound debridement by a general surgeon.

Pseudallescheria boydii an emerging pathogen of humans is a filamentous fungus frequently isolated from respiratory infections. It is commonly believed that infection by this fungus occurs through inhalation of airborne conidia, but the mechanisms allowing the adherence of Pseudallescheria to the host epithelial cells and its escape from the host immune defences remain largely unknown. This fungus causes a wide array of human infections that can affect practically all the organs of the body. Disseminated and invasive infections with this fungus are seen primarily in immunocompromised hosts.Here, we report a case of unilateral maxillary sinusitis caused by P. boydii in an immunocompetant male. The patient was surgically treated and was followed up with antifungal and is free of symptoms, with no recurrence after 6 months.