Molecular insights into the SARS-CoV-2 Omicron variant from Bangladesh suggest diverse and continuous evolution.

The study analyzed the molecular dynamics of the circulating SARS-CoV-2 Omicron variant from its identification in November 2021 to January 2023. The SARS-CoV-2 sequences from Bangladesh revealed three distinct waves of the Omicron variant. More than 50 sub-lineages of Omicron variant were introduced into the country, with the majority belonging to the major lineages of BA.1-like (24.91%), BA.2-like (43.35%), BA.5-like (5.76%), XBB (10.47%), and "Others and Unassigned" (18.64%). Furthermore, the relative frequencies over time revealed that Omicron lineages existed for a short period of time before being replaced by other sub-lineages. Many potential mutations were found in the receptor binding domain of the Spike protein including G339D/H, S371 L/F, K417 N, T478K, E484A, Q493R, Q498R, and N501Y. In conclusion, the SARS-CoV-2 Omicron variant from Bangladesh showed diverse genetic features and continuous evolution. Therefore, the choice of vaccine and monitoring of hospitalized patients is important alongside genetic characterization of the circulating SARS-CoV-2.

Prevalence and Antifungal Susceptibility of Clinically Relevant Candida Species, Identification of Candida auris and Kodamaea ohmeri in Bangladesh.

Candida species are major fungal pathogens in humans. The aim of this study was to determine the prevalence of individual Candida species and their susceptibility to antifungal drugs among clinical isolates in a tertiary care hospital in Bangladesh. During a 10-month period in 2021, high vaginal swabs (HVSs), blood, and aural swabs were collected from 360 patients. From these specimens, Candida spp. was isolated from cultures on Sabouraud dextrose agar media, and phenotypic and genetic analyses were performed. A total of 109 isolates were recovered, and C. albicans accounted for 37%, being derived mostly from HVSs. Among non-albicans Candida (NAC), C. parapsilosis was the most frequent, followed by C. ciferrii, C. tropicalis, and C. glabrata. Three isolates from blood and two isolates from aural discharge were genetically identified as C. auris and Kodamaea ohmeri, respectively. NAC isolates were more resistant to fluconazole (overall rate, 29%) than C. albicans (10%). Candida isolates from blood showed 95% susceptibility to voriconazole and less susceptibility to fluconazole (67%). Two or three amino acid substitutions were detected in the ERG11 of two fluconazole-resistant C. albicans isolates. The present study is the first to reveal the prevalence of Candida species and their antifungal susceptibility in Bangladesh.

Dynamics of SARS-CoV-2 variants of concern (VOC) in Bangladesh during the first half of 2021.

Bangladesh is the second-worst-affected country in South Asia by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this study is to examine genome sequences from Bangladesh from January 2021 to June 2021 in order to monitor the SARS-CoV-2 VOC and the clades or lineages that are prevalent in the country. Within the study timeframe, at least eight Nextstrain clades were found: 20A, 20B, 20C, 20H (Beta, V2), 20I (Alpha, V1), 20 J (Gamma, V3), 21A (Delta), 21D (Eta), and six GISAID clades: four main (G, GH, GR, GRY) and two minors (GV, O) with an introduction of VOC B.1.1.7/Alpha, B.1.351/Beta and B.1.617.2/Delta. The introduction and recent occurrence of VOCs with substantial alterations in the receptor binding site of spike protein (K417 N, K417T, L452R, T478K, E484K, S494P, N501Y) are of particular importance. Specifically, VOC B.1.617.2/Delta has surpassed all prior VOCs in Bangladesh, posing a challenge to the existing disease management.

Molecular Analysis of SARS-CoV-2 Circulating in Bangladesh during 2020 Revealed Lineage Diversity and Potential Mutations.

Virus evolution and mutation analyses are crucial for tracing virus transmission, the potential variants, and other pathogenic determinants. Despite continuing circulation of the SARS-CoV-2, very limited studies have been conducted on genetic evolutionary analysis of the virus in Bangladesh. In this study, a total of 791 complete genome sequences of SARS-CoV-2 from Bangladesh deposited in the GISAID database during March 2020 to January 2021 were analyzed. Phylogenetic analysis revealed circulation of seven GISAID clades G, GH, GR, GRY, L, O, and S or five Nextstrain clades 20A, 20B, 20C, 19A, and 19B in the country during the study period. The GISAID clade GR or the Nextstrain clade 20B or lineage B.1.1.25 is predominant in Bangladesh and closely related to the sequences from India, USA, Canada, UK, and Italy. The GR clade or B.1.1.25 lineage is likely to be responsible for the widespread community transmission of SARS-CoV-2 in the country during the first wave of infection. Significant amino acid diversity was observed among Bangladeshi SARS-CoV-2 isolates, where a total of 1023 mutations were detected. In particular, the D614G mutation in the spike protein (S_D614G) was found in 97% of the sequences. However, the introduction of lineage B.1.1.7 (UK variant/S_N501Y) and S_E484K mutation in lineage B.1.1.25 in a few sequences reported in late December 2020 is of particular concern. The wide genomic diversity indicated multiple introductions of SARS-CoV-2 into Bangladesh through various routes. Therefore, a continuous and extensive genome sequence analysis would be necessary to understand the genomic epidemiology of SARS-CoV-2 in Bangladesh.