Bangladesh Journal of Microbiology <p>The official journal of the Bangladesh Society of Microbiologists. Full text articles available</p> en-US (Professor Mahmuda Yasmin) (Md Fahmid Uddin Khondoker) Mon, 10 Jun 2024 09:18:04 +0000 OJS 60 Textile Dye Decolorization Potential of Bacillus pumilus and Staphylococcus saprophyticus Isolated From Textile Industry Effluents <p>Textile dyeing industries are usually chastised for being big polluters due to the poisonous nature of most dyes, which endangers all kinds of life, including people. In this study, dye degrading bacteria were isolated from water and soil samples contaminated with textile dye taken from Batik palli in Narayanganj and the ability of five isolated bacteria including Staphylococcus saprophyticus, Bacillus pumilus, Micrococcus endophyticus, Pseudomonas mendocina, and Acinetobacter baumannii, to decolorize crystal violet (CV) dye was investigated. Among these, Bacillus pumilus decolorized 58% of CV at 250 ppm, while Staphylococcus saprophyticus decolorized 48% of CV, after 3 days of incubation at 37°C. We examined multiple temperature and pH conditions to determine the best parameters for CV dye decolorization. Bacillus pumilus boosted decolorization rates by 65.39% at 37°C and at pH 7.0, while Staphylococcus saprophyticus increased decolorization rates by 58.73%, at 37°C and at pH 5.0. Furthermore, extending the incubation period to 6 days enhanced decolorization rate in both isolates, with Bacillus pumilus increased from 58% to 65% and Staphylococcus saprophyticus increased from 48% to 58%. Nevertheless, the inclusion of co-substrates such glucose and yeast extract further boosting decolorization rate for both isolates, approximately tripling it. As a result, this study discovered indigenous bacteria capable of decolorizing CV dye, implying that they could be employed in the treatment of textile wastewater effluents.</p> <p>Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 50-54</p> Nayeema Talukder Ema, Zannatul Mayua, Imtiaj Uddin Bhuyian, Anowara Begum, Humaira Akther, Sangita Ahmed Copyright (c) 2023 Bangladesh Journal of Microbiology Mon, 10 Jun 2024 00:00:00 +0000 Isolation of Potential Azo dye Degrading/Tolerating Bacteria from Polluted Environment <p>Various industries including the food and textile industries result in the release of azo dyes into the environment. These dyes are known to exert toxic effects on humans, animal and plants. Biological methods of azo dye bioremediation is a solution for the detoxification of azo dye in the environment. The present study was undertaken to isolate bacteria with potential for azo dye bioremediation. From five polluted environment samples, eight bacteria were isolated in azo dye supplemented Nutrient agar. Six isolates (75%, n=8) decolorized azo dye completely following 24 hours of incubation. The control tube with no bacterial inoculation remained blue, indicating that only microbial biotransformation processes were taking place. In each case, a blue-colored ring remained at the top, indicating the anoxic nature of the dye decolorization process. All isolates grew in presence of 400 ppm, 60% tolerated 600 ppm and 20% tolerated 800 ppm, whereas 1000ppm was inhibitory for growth of all isolates. Dead autoclaved cells of three representative isolates were tested for biosorption potential. Only one isolate turned the methylene blue supplemented nutrient broth colorless. This explains that this isolate was not metabolizing methylene blue rather it bound the dye to the cell structure. Two isolates did not show biosorption abilities indicating that their mechanism of bioremediation was enzymatic reduction. 16s rDNA sequencing identified two of the isolates as Lysinibacillus capsici and Stenotrophomonas muris.</p> <p>Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 56-59</p> Monira Mehzabin, Sunjukta Ahsan Copyright (c) 2023 Bangladesh Journal of Microbiology Mon, 10 Jun 2024 00:00:00 +0000 Biofilm-Producing and Specific Antibiotic Resistance Genes in Pseudomonas aeruginosa Isolated from Patients Admitted to a Tertiary Care Hospital, Bangladesh <p><em>Pseudomonas aeruginosa</em> is one of the organisms well-known for producing biofilm. Biofilms are responsible for persistent infections and antimicrobial resistance. The aim of this was to investigate <em>P. aeruginosa </em>for its ability to form biofilm. Genes that were responsible for the production of biofilms and biofilm-specific antimicrobial resistance were detected. The association between antibiotic resistance and biofilm was investigated. This cross-sectional study was conducted from July 2017 to December 2018. A total of 446 samples (infected burns, surgical wounds, and ETA) were collected from admitted patients at Dhaka Medical College and Hospital, Bangladesh. <em>P. aeruginosa</em> was isolated and identified by biochemical tests and PCR. Biofilm production by the tissue culture plate (TCP) method was followed by the detection of biofilm[1]producing genes (<em>pqs</em>A, <em>psl</em>A, <em>psl</em>D, <em>psl</em>H, <em>pel</em>A, <em>las</em>R) and biofilm-specific antibiotic resistance genes (<em>ndv</em>B, PA1874, PA1876, PA1877) by PCR. The antibiotic susceptibility test was carried out by the disc diffusion method; for colistin agar dilution, the MIC method was followed. Among 232 (52.02%) positive strains of <em>P. aeruginosa</em>, 24 (10.30%) produced biofilms in TCPM. Among biofilm-producing genes, <em>pqs</em>A was found the highest number of isolates (79.17%), which was followed by <em>psl</em>A and <em>pel</em>A (70.83%). Other were found in lesser extent. Among the biofilm-specific antibiotic resistance genes, 16.67% of the isolates had <em>ndv</em>B, and 8.33% had PA1874 and PA1877. Biofilm-forming strains were significantly resistant to colistin in comparison to non-biofilm-forming ones. In conclusion, detection of biofilm-forming genes may be a good tool for the evaluation of biofilm production, which will help in prompt and better management of chronic or device-associated infections.</p> <p>Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 60-65</p> Rubaiya Binte Kabir, Tasnim Ahsan, Md Faizur Rahman, Mohammad Jobayer, SM Shamsuzzaman Copyright (c) 2023 Bangladesh Journal of Microbiology Mon, 10 Jun 2024 00:00:00 +0000 Diversity of Plant Growth Promoters (PGP) Isolated from Agricultural Fields of Bangladesh <p>With an emphasis on leguminous plants like <em>Glycine max</em> (soybean), <em>Clitoria ternatea</em>, and non-leguminous plants like <em>Phaseolus lunatus</em>, this study investigates the diversity of Plant Growth-Promoting Rhizobacteria (PGPR) isolated from the root nodules and rhizospheres of agricultural soil. Seventeen of the 42 isolates were chosen for further analysis. Isolates were screened through phenotypic characterization, presumptive identification, and evaluation of their plant growth-promoting (PGP) qualities. Amplification of the nitrogen[1]fixing <em>nif</em>H gene, the nodulation-inducing <em>nod</em>C gene, and the 16S rRNA were among the molecular investigations carried out. Three examined PGP features were present in 35% of the isolates, according to the results. From pH levels of 4.5 to 9, temperatures of 37oC to 40oC and salt concentrations of 1% or less, the isolates showed versatility in a variety of environmental circumstances. Resistant to high temperatures (40°C), slow-growing rhizobia (22%) were shown to be sensitive to high pH (9). Tilt and Tafgor pesticides had a more severe influence on PGP traits and development than Shadhin G and Semcup. The design and efficacy of biofertilizers, agro-economic progress, and sustainable agriculture are among the topics on which this qualitative study sheds important light.</p> <p>Bangladesh J Microbiol, Volume 40, Number 2, &nbsp;December 2023, pp 66-74</p> Halima Habib, Shammi Akhter Trishna, Anowara Begum, Humaira Akhter Copyright (c) 2023 Bangladesh Journal of Microbiology Mon, 10 Jun 2024 00:00:00 +0000 Antimicrobial and Membrane Stabilization Activity of Plant Extracts Against Pathogenic Bacteria and Fungi <p>The use and search for antimicrobial drugs derived from plants have accelerated in recent years. The present study was aimed to determine the antimicrobial, antibiofilm and membrane stabilization activities of plant extracts. Crude extracts of four plants namely, <em>Mikania scandens</em> (L.), <em>Mimosa pudica</em> (L.), <em>Murraya paniculata</em> (L.), and <em>Syzygium aromaticum</em> (L.) were tested against eleven human pathogens including four biofilm producing bacterial strains <em>Escherichia coli</em>, <em>Pseudomonas aeruginosa</em>, <em>Klebsiella pneumoniae</em> and <em>Staphylococcus aureus</em>, and one fungal strain <em>Candida albicans</em>. The antimicrobial activities as well as minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts were evaluated using disc diffusion and macro-broth dilution methods respectively. Among the plant extracts, ethanol extract of <em>S. aromaticum</em> exhibited the largest zone of inhibition 35 mm in diameter against <em>Bacillus subtilis</em> at 500 µg/disc concentrations. The lowest MIC (1000 µg/ml) and MBC (2500 µg/ml) were determined against <em>P. aeruginosa</em> with the same extract of <em>S. aromaticum</em>. In case of time kill assay, <em>S. aromaticum</em> extract showed the lowest optical density (OD<sub>600</sub>) 0.2 against <em>E coli</em> in 3h at MBC concentration. Moreover, the same extract of <em>S. aromaticum</em> displayed the strong antibiofilm activity, inhibiting 100% biofilm formation of <em>E. coli</em> at 2×MIC concentration. Furthermore, <em>in vitro</em> experiment was performed to evaluate membrane stabilization activity of plant extracts and <em>S. aromaticum</em> showed 100% activity in stabilizing cell membranes, preventing hemolysis of red blood cells. Therefore, this study provides valuable insight for designing antimicrobial products to efficiently eliminating human infections, and the plant extracts could be the potential antimicrobial agent.</p> <p>Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 76-85</p> Nadia Islam Tumpa, Md Shafiqur Rahman, Mohammed Abul Manchur Copyright (c) 2023 Bangladesh Journal of Microbiology Mon, 10 Jun 2024 00:00:00 +0000 Detection of Thermoacidophiles from Yellowstone Hot Spring <p>Aerobic methanotrophic bacteria maintain an unrivalled capability of utilizing methane as their sole carbon and energy source and have been retrieved from various environments. Phylogenetically, true aerobic thermoacidophilic methane oxidizers capable of growing below pH 3 have hitherto been associated only with the phylum <em>Verrucomicrobia</em>. In this report, the initial detection of a moderately thermoacidophilic <em>Methylococcus</em>-like Type Ib methanotroph of the class <em>Gammaproteobacteria </em>from an acidic thermal spring (50oC and pH 2.8) in the Yellowstone National Park, USA is presented. The isolate, termed YT-MC, was identified in a methane enrichment (55°C), which may represent a novel strain in the family <em>Methylococcaceae</em> Type Ib. The existence of this bacterium in the enrichments was demonstrated by the detection of pmoA gene, Southern blotting technique, phase-contrast, and electron microscopy. The coccus-typed cells showed tubular membranes instead of intracytoplasmic membrane systems (ICM). The soluble methane monooxygenase (sMMO) was not detected by PCR, indicating that the biotransformation of methane to methanol is oxidized by the particulate methane monooxygenase (pMMO). Moreover, YT-MC performs in a formerly undiscovered active biological methane sink in geothermal acidic environments, magnifying our knowledge of its ecological role in methane cycling, diversity, and coexistence of aerobic methanotrophy. Furthermore, the present study also reports the isolation and identification of an alphaproteobacterial heterotroph (strain YT-AC) and a verrucomicrobial methanotroph (strain YT-VM) from the same environment.</p> <p>Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 86-94</p> Tajul Islam, Ruben Michael Ceballos, Lise Øvreås Copyright (c) 2023 Bangladesh Journal of Microbiology Mon, 10 Jun 2024 00:00:00 +0000