Arsenic (As) contaminated soils are enriched with arsenotrophic bacteria. The present study analyzes the microbiome and arsenotrophic genes-from As affected soil samples of Bhanga, Charvadrason and Sadarpur of Faridpur district in Bangladesh in summer (SFDSL1, 2, 3) and in winter (WFDSL1, 2, 3). Total As content of the soils was within the range of 3.24–17.8 mg/kg as per atomic absorption spectroscopy. The aioA gene, conferring arsenite [As (III)] oxidation, was retrieved from the soil sample, WFDSL-2, reported with As concentration of 4.9 mg/kg. Phylogenetic analysis revealed that the aioA genes of soil WFDSL-2 were distributed among four major phylogenetic lineages comprised of α, β, γ Proteobacteria and Archaea with a dominance of β Proteobacteria (56.67 %). An attempt to enrich As (III) metabolizing bacteria resulted 53 isolates. ARDRA (amplified ribosomal DNA restriction analysis) followed by 16S rRNA gene sequencing of the 53 soil isolates revealed that they belong to six genera; Pseudomonas spp., Bacillus spp., Brevibacillus spp., Delftia spp., Wohlfahrtiimonas spp. and Dietzia spp. From five different genera, isolates Delftia sp. A2i, Pseudomonas sp. A3i, W. chitiniclastica H3f, Dietzia sp. H2f, Bacillus sp. H2k contained arsB gene and showed arsenite tolerance up-to 27 mM. Phenotypic As (III) oxidation potential was also confirmed with the isolates of each genus and isolate Brevibacillus sp. A1a showed significant As (III) transforming potential of 0.2425 mM per hour. The genetic information of bacterial arsenotrophy and arsenite oxidation added scientific information about the possible bioremediation potential of the soil isolates in Bangladesh.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-016-0193-0) contains supplementary material, which is available to authorized users.

Arsenotrophic bacteria contribute to the nutrient cycling in arsenic (As) affected groundwater. This study employed a culture-independent and -dependent investigation of arsenotrophic microbiomes in As affected groundwater samples collected from Madhabpur, Sonatengra, and Union Porishod in Singair Upazila, Manikganj, Bangladesh. Total As contents, detected by Atomic Absorption Spectrophotometry (AAS) of the samples, were 47 µg/L (Madhabpur, SNGW-1), 53 µg/L (Sonatengra, SNGW-2), and 12 µg/L (Union porishod, SNGW-3), whereas the control well (SNGW-4; depths >150 m) showed As content of 6 µg/L. Denaturing Gradient Gel Electrophoresis (DGGE) analysis of the amplified 16S rRNA gene from As-affected groundwater samples revealed the dominance of aerobic bacteria Pseudomonas within heterogeneous bacterial populations. DGGE of heterotrophic enrichments supplemented with arsenite [As (III)] for 4 weeks showed the dominance of Chryseobacterium, Flavobacterium, and Aquabacterium, whereas the dominant genera in that of autotrophic enrichments were Aeromonas, Acinetobacter, and Pseudomonas. Cultured bacteria retrieved from both autotrophic and heterotrophic enrichments were distinguished into nine genotypes belonging to Chryseobacterium, Acinetobacter, Escherichia, Pseudomonas, Stenotrophomonas, Janibacter, Staphylococcus, and Bacillus. They exhibited varying range of As(III) tolerance from 4 to 27 mM. As(III) transformation potential was confirmed within the isolates with oxidation rate as high as 0.143 mM/h for Pseudomonas sp. Sn 28. The arsenotrophic microbiome specifies their potential role in groundwater As-cycling and their genetic information provide the scientific basis for As-bioremediation.

Chromium (Cr) (VI) has long been known as an environmental hazard that can be reduced from aqueous solutions through bioremediation by living cells. In this study, we investigated the efficiency of reduction and biosorption of Cr(VI) by chromate resistant bacteria isolated from tannery effluent. From 28 screened Cr(VI) resistant isolates, selected bacterial strain SH-1 was identified as Klebsiella sp. via 16S rRNA sequencing. In Luria–Bertani broth, the relative reduction level of Cr(VI) was 95%, but in tannery effluent, it was 63.08% after 72 h of incubation. The cell-free extract of SH-1 showed a 72.2% reduction of Cr(VI), which indicated a higher activity of Cr(VI) reducing enzyme than the control. Live and dead biomass of SH-1 adsorbed 51.25 mg and 29.03 mg Cr(VI) per gram of dry weight, respectively. Two adsorption isotherm models—Langmuir and Freundlich—were used for the illustration of Cr(VI) biosorption using SH-1 live biomass. Scanning electron microscopy (SEM) analysis showed an increased cell size of the treated biomass when compared to the controlled biomass, which supports the adsorption of reduced Cr on the biomass cell surface. Fourier-transform infrared analysis indicated that Cr(VI) had an effect on bacterial biomass, including quantitative and structural modifications. Moreover, the chickpea seed germination study showed beneficial environmental effects that suggest possible application of the isolate for the bioremediation of toxic Cr(VI).

Here, we report the coding-complete genome sequences of nine clinical severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and their mutations. The samples were collected from nine Bangladeshi coronavirus disease 2019 (COVID-19) patients. We have identified the E484K escape mutation and the S359T mutation within the spike protein coding region of the sequenced genomes.

Background: Socio-demographic variability among nations and cultures highly influences health-seeking behavior (HSB) in managing endemic or pandemic diseases. The present study aimed to investigate the influence of socio-demographic factors on HSB among Bangladeshi residents during the first wave of COVID-19. Methods: A cross-sectional online survey was performed with Bangladeshi residents (60% male and 40% female; age range: 10–60 years or above) from May to July 2020. Information was collected from the participants who resided in slum areas or did not have internet access through face-to-face surveys, maintaining spatial distancing and proper preventive measures. A self-reported and structured questionnaire, including socio-demographic and HSB, was undertaken, and the data was analyzed using a convenience sampling method. Finally, among the 947 participants, 20 were selected using a stratified random sampling technique for in-depth-interview (IDI). The linear regression analysis was performed to determine the influence of socio-demographic factors on HSB. Results: Only about 4.2% of respondents did not wear masks, but nearly half of the participants (46.6%) did not use hand gloves. The mean score of HSB was 9.98 (SD = 2.01) out of 16, with a correct overall rate of 62.4%. As per regression analysis, higher HSBs were found among participants who reported older age (>50 years) (9.96 ± 2.45), educated unemployed students (10.1 ± 1.95), higher education (10.5 ± 1.76), and higher-income (10.4 ± 1.59); in contrast, participants living in slum areas (8.18 ± 2.34) and whose source of income was business (8.46 ± 2.04) exhibited lower HSBs. Females, compared to men, showed better HSB in every aspect, apart from online food ordering. Qualitative data showed that the younger generation is more aware because of their access to information and persuaded the older generations to follow health-seeking protocols. The results also showed that some lower-income slum-dwellers have access to information and healthcare through their employers. IDIs also found cultural, religious, and mental-health affect people’s adherence to health-seeking guidelines and regulations. Conclusions: The findings suggest that socio-demographic factors significantly influenced HSBs during COVID-19 in the Bangladeshi population. Authorities can use these observations to systematically manage future endemics or pandemics.

Physicochemical properties and metal contents of five dye-based textile effluents collected in summer and winter season, 2016 from Savar, Dhaka, Bangladesh were within the recommended acceptable limit. The average value of all physicochemical parameters was found high in summer season except turbidity. A total of 94 heavy metal resistant bacteria (46 gram positive & 48 gram negative) were isolated from textile effluent samples and among them 17 isolates were multi metal resistant. Highest tolerance level of the isolates was shown at 10 mM concentration against Pb. All the heavy metal resistant bacterial isolates were presumably grouped into 14 genera according to morphological and biochemical assay. Three isolates designated WFB3c (65.41%), WFB4g (62%) and SFB5c (60.07%) were found to potentially degrade dye as well as tolerate heavy metals. Three potential dye decolorizer isolates were screened out and most potential one (WFB3c) was identified as Proteus mirabilis according to the 16S rRNA identification. The isolated bacterial strain Proteus mirabilis would be a potential candidate for microbes based treatment to decolorize dye from textile effluents.

Objective: At the start of the Covid-19 pandemic, educational establishments, including universities, were closed. Educators in high-income countries quickly shifted all education online, building on available infrastructures and approaches. However, there were concerns in developing countries regarding the necessary skills among students and faculty as well as financial support for equipment and the internet. Consequently, a pilot was undertaken in Bangladesh to determine the impact of Covid-19 on the non-medical education system, building on similar research with healthcare professionals. Materials and Methods: A purposively designed questionnaire was disseminated among eight non-medical healthcare educators in private and public universities in Bangladesh. Results and Discussion: Private university educators reported their universities readily adopted e-learning systems and resumed classes more quickly than public universities. Both private and public university educators shared similar challenges, including a lack of training on e-learning initially, variable internet connections, affordability of internet bundles, concerns with available devices, as well as mental stress of faculty and students. Private universities reduced their tuition fees, extended submission deadlines, and shared class recordings to address challenges. Public universities arranged student loans, established Covid-19 testing centers, and the trained students in biosafety practices and molecular tests to volunteer in testing facilities. Conclusion: Lessons learned from the pandemic emphasize introducing hybrid education systems with full technological and financial support, alongside biosafety education in the curriculum. Bangladesh Journal of Medical Science Vol. 21 No. 04 October’22 Page : 731-743

Successful treatment against infectious agents depends on rapid and accurate detection of the causative organisms. Misdiagnosis can hamper such success while leading to improper advising of antibiotics. In Bangladesh, the majority of the diagnostic centers detect and identify pathogens through culture and biochemical test-based methods and suggest antibiotics based solely on the results of disk-diffusion methods. This pilot study tried to validate the identity of the isolates characterized by diagnostic facilities near Dhaka. One hundred and twenty pre-characterized clinical isolates were analyzed biochemically and genotypically. Random Amplification of Polymorphic DNA-PCR, rcsA, and phoA genes-based PCR, and Loop-Mediated Isothermal Amplification (LAMP)-based identification of Klebsiella pneumoniae and Escherichia coli, respectively, followed by 16S rRNA sequencing confirmed misidentification of some clinical pathogens of other genera as Klebsiella spp. and E. coli. According to the antibiotic susceptibility testing guidelines, antibiotic choice, sensitivity pattern, and breakpoint measurement are different for each group of organisms. The lack of adherence to proper standards results in misdiagnosis and may facilitate the development of antibiotic resistance. The pilot study observers misidentification of clinical pathogens identified by the diagnostic centers. Well-characterized rapid molecular techniques like LAMP are suggested in clinical diagnosis to avoid misdiagnosis and subsequently circumvent antibiotic resistance development.