Bangladesh Journal of Microbiology Full text articles available en-US (Professor Mahmuda Yasmin) (Md Fahmid Uddin Khondoker) Sun, 08 Dec 2019 09:05:28 +0000 OJS 60 Preliminary characterization and inhibitory activity of bacteriocin like substances from Lactobacillus casei against multi-drug resistant bacteria <p>Antimicrobial resistance is a mounting threat to the control of infectious diseases worldwide. Due to the increasing rate of drug resistance, there is continuous requirement for new and safe antimicrobial agents both for therapeutic purposes and food industries. The potential of bacteriocin has attracted much attention in recent years.We characterized bacteriocin like substances produced by <em>Lactobacillus casei</em>. This bacterium produces bacteriocin like substances that have the ability to inhibit multi-drug resistant pathogenic bacteria such as <em>Staphylococcus</em> <em>aureus, Klebsiella pneumoniae, </em>and <em>Proteus vulgaris</em>. To investigate the antimicrobial property of the bacteriocin like substances produced by <em>L.casei</em>, cell free supernatant (CFS) was prepared and antagonistic activity of cell free supernatant was determined by agar well diffusion method. Production of bacteriocin like substances was greatly affected by nutrient media, pH, temperature and incubation period. Highest inhibitory activity was observed when <em>L.casei </em>was grown in MRS broth (De Man, Rogosa and Sharpe broth) (pH 4.0) for 72 hoursat 37°C. The active components of CFS responsible for antagonistic activity are proteinaceous in nature since they are susceptible to heat treatment. Partial purification of this CFS was done by organic solvent extraction method. Among the eight isolates tested, only <em>S. auereus, Proteus vulgaris </em>and <em>K. pneumoniae </em>showed more sensitivity to the partially purified crude bacteriocin like substances (CBLS) than CFS.</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 01-06</p> Farzana Binte Hasan, Mahin Reza, HM Abdullah Al Masud, Md Kamal Uddin, Mohammad Seraj Uddin ##submission.copyrightStatement## Sun, 08 Dec 2019 09:02:27 +0000 Genetic diversity of Rhizobium spp. isolated from soil samples of Bangladesh <p>Rhizobia are Gram-negative soil-inhabiting bacteria commonly found in nodules of leguminous plants. These bacteria exclusively fix atmospheric nitrogen into ammonia, which is convertible to urea to serve natural fertilizer to the plants. However, rhizobial microbiota of Bangladesh have been studied poorly. Here, twenty isolates were identified as <em>Rhizobium </em>through observation of cultural characteristics, morphological characteristics and different biochemical tests. Isolates differed from one another in terms of their stress response characteristics like salt-stress tolerance,temperature tolerance, antibiotic susceptibility, and pH. Most of the isolates were resistant to ampicillin and erythromycin and streptomycin; and were sensitive to kanamycin and ciprofloxacin. Isolates were clustered into three genotypic groups according to the banding patterns of Amplified Ribosomal DNA Restriction Analysis (ARDRA). All the strains in ARDRA group 1 were <em>Rhizobium azibense</em>, and the others were <em>Rhizobium bangladeshense </em>and <em>Rhizobium qilianshanense</em>. Future studies would validate their capacity of nitrogen fixation and the scope of improvement of these strains to increase their efficiency of nitrogen fixation.</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 07-10</p> Md Tauhidul Islam Tanim, Md Miraj Kobad Chowdhury, Latiful Bari, Md Mizanur Rahaman, Sabita Rezwana Rahman, Md Majibur Rahman ##submission.copyrightStatement## Sun, 08 Dec 2019 09:02:37 +0000 Cross-reacting surface proteins between different Escherichia coli O157:H7 strains and their immune responses in animal models <p>Surface proteins of <em>Escherichia coli </em>O157:H7, those that are prominent in antigen-antibody reactions among different strains, were found to provide protection against <em>E. coli </em>O157 challenge in mice. Three strains such as <em>E. coli</em> O157:H7 NCTC reference strain and two other environmentally isolated strains have been used in this study. New Zealand rabbits were immunized with surface proteins of NCTC reference strain and immunoblot analysis was performed against the surface proteins of all three strains. Immunoblot analysis revealed that a 94 kDa surface protein of <em>E. coli </em>O157:H7 could be the possible candidate for the protective activity experiment. Group of mice receiving the 94 kDa surface protein through both intraperitoneal and intranasal routes survived the challenge experiment. Whereas, all the control mice died within a couple of days. Mice challenge experiment clearly demonstrated the strong potential of the 94 kDa protein in the immunized mice. The data of this study provide us with a basis for further characterization of 94 kDa surface protein of <em>E. coli </em>O157:H7 as a protective antigen.</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 11-15</p> Ashikun Nabi, Fatema Moni Chowdhury, Zeenat Jahan, Md Murshed Hasan Sarkar, Fazle Rabbi, Chowdhury Rafiqul Ahsan ##submission.copyrightStatement## Sun, 08 Dec 2019 09:02:45 +0000 Isolation and partial characterization of organophosphate pesticide degrading bacteria from soil sample of Noakhali, Bangladesh <p>Extensive use of organophosphate pesticides particularly malathion can result in pollution of soil, surface water and ground water, and thus disrupts ecosystem byexposing non-target species to its toxicity. Bioremediation with indigenous microorganisms having pesticide utilizing abilities is considered to be a viable solution regarding decontamination of organophosphate residues from pesticide contaminated soil. In this study, we isolated five malathion degrading bacter ial strains designated as S-1, S-2, S-3, S-4 and S-5 from paddy fields of Noakhali, Bangladesh by observing visible growth in malathion supplemented mineral salts medium (MSM) agar following selective enrichment technique. The isolates were provisionally identified based on their morphological and biochemical characteristics as <em>Pseudomonas </em>spp. (S-1)<em>, Bacillus subtilis </em>(S-2)<em>, Staphylococcus aureus </em>(S-3)<em>,</em> <em>Pseudomonas aeruginosa </em>(S-4) and <em>Pseudomonas </em>spp. (S-5) respectively. To determine their malathion utilization potential, the isolates were inoculated in MSM containing 50 mg/l malathion as sole source of carbon. When compared with control, the turbidometric growth study with the isolates revealed that all the isolates showed a significant increase of growth, indicating utilization of malathion (conc. 50 mg/l) in MSM at 37oC. The rate of growth varied for all the isolates when this growth study was done using different temperature schemes (25<sup>o</sup>C, 35<sup>o</sup>C and 45<sup>o</sup>C).</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 17-22</p> Mahin Reza, Jannatul Fiza, Foysal Hossen, Firoz Ahmed ##submission.copyrightStatement## Sun, 08 Dec 2019 09:02:54 +0000 Prevalence of Methicillin and Vancomycin resistant Staphylococcus aureus on the touch screen of automated teller machines in Dhaka city. <p>The present study was undertaken to observe the transmission of microbial contaminants through different electronic devices. Five different bacteria such as <em>Escherichia coli</em>, <em>Staphylococcus aureus</em>, <em>Staphylococcus epidermidis</em>, <em>Pseudomonas </em>spp. and <em>Bacillus </em>spp. were cultivated from the surface of 50 different automated teller machines (ATMs) of 10 different banks located in Dhaka City. Among them, the number of <em>Pseudomonas </em>spp. and <em>S. epidermidis</em> were found up to 104 cfu/ml while the <em>S. aureus </em>was quantified up to 106 cfu/ml. Fungal contamination was also observed in all cases within the range of 104 and 105cfu/ml. Most of the isolates were found to be resistant against more than one antibiotic. Only Streptomycin and Gentamicin were found to be effective against all the bacteria. Out of 50 strains (coagulase positive) of <em>S. aureus</em>, 40 (80%) were found as Oxacillin and Methicillin resistant. Among 40 MRSA strains, 25 (62.5%) were found to be resistant against vancomycin which is referred to as VRSA. The isolated MDR bacteria from the surface of the ATM may be a health concern for the users</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 23-27</p> Mrityunjoy Acharjee, Takia Akter, Nafisa Tabassum, M Majibur Rahaman, Rashed Noor ##submission.copyrightStatement## Sun, 08 Dec 2019 09:03:02 +0000 Detection of New Delhi Metallo b Lactamase gene in Uropathogenic E. coli <p>The rapid dissemination of antibiotic resistant <em>E. coli </em>is now a worldwide problem. In this study, a total of twenty <em>E. coli </em>obtained from stool were selected to determine resistance to beta lactam antibiotics. Beta–Lactamase are enzymes produced by bacteria that provide multi resistance to beta lactam antibiotics such as penicillin, cephalosporin, cephamycin and carbapenems. Of these isolates (n = 20), 35% were found resistant to Amoxicillin Clavulanate, 5% to Imipenem, 50% to Ceftriaxone and 75% to Ampicillin. PCR amplification confirmed the presence of the New Delhi beta-lactamase gene (bla<sub>NDM</sub>) in one isolate (5%, n=20). Plasmids of variable sizes were found in all the isolates. Beta lactam antibiotics are now commonly used for the treatment of disease. Resistance of 50% of the isolates to Ceftriaxone is alarming as this indicates that an alternative drug may soon need to replace this antibiotic for successful treatment. The finding of this study is also of public health concern as plasmids were found in most isolates and these mobile genetic elements can be transferred among clinical bacteria, thereby disseminating antibiotic resistance further limiting treatment options.</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 29-33</p> Sunjukta Ahsan, Anindita Bhowmik, Sharmistha Goswami, Nasir Uddin ##submission.copyrightStatement## Sun, 08 Dec 2019 09:03:10 +0000 Emerging Technologies for Food Safety: High Pressure Processing (HPP) and Cold Plasma Technology (CPT) for Decontamination of Foods <p>Foods may become contaminated from a variety of sources, therefore it is imperative to understand and discover easy, cheap and effective means of decontaminating foods. Heat, although effective, economical and easily available, has been reported to produce undesirable effects on food such as loss of taste and nutrition. High Pressure Processing can inactivate the cells of the food borne pathogens and organisms responsible for food spoilage regardless of the temperature without making changes to the texture, color or flavor. Equipment involved in HPP includes a pressure vessel, pumps generating high hydrostatic pressure or intensifiers. Its success depends on certain factors such as pressure of water, temperature used during the treatment, and the properties and state of the food and categories of microorganisms found in food.Cold Plasma Technology (CPT) is a novel, non-thermal food processing technology that uses energetic and reactive gases to inactivate contaminating microorganisms in food products. CPT is environmentally friendly that uses natural gases such as nitrogen, argon, air, hydrogen, and oxygen. Depending on the plasma type, it can inactivate a wide range of microorganisms including food borne pathogens and spoilage organisms. This technology hasa low running cost (Cost of natural gases and electricity).Both HPP and CPT can spread and work on the entire food sample, regardless of shape and size. These methods serve as an alternative to some methods which were previously used.</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 35-43</p> Farahnaaz Feroz, Showshan Nafisa, Rashed Noor ##submission.copyrightStatement## Sun, 08 Dec 2019 09:03:18 +0000 Bacteriological Status of Street Foods in Different University Premises of Dhaka City, Bangladesh <p>Street food contamination is common and has a potential health hazards throughout the world. These categories of foods are very popular among the students of Academic Institutions (Universities) of Dhaka city, Bangladesh for their appealing look and reasonable cost. This study was conducted to determine the presence of <em>E. coli</em>, <em>Shigella </em>sp. and <em>Vibrio </em>sp. in the street foods. Two hundred and forty-two food samples were collected from 20 University premises of Dhaka city. Biochemical tests were performed on suspected colonies for the identification of the relevant bacteria obtained from the samples. <em>E. coli</em>, <em>Vibrio </em>sp., and <em>Shigella </em>sp. were identified in 18% samples, where <em>E.</em> <em>coli </em>was found in 12%, <em>Vibrio </em>sp<em>. </em>was identified in 5%, and <em>Shigella </em>sp. in &lt;1.0% food sample studied. The samples from which <em>E. coli </em>and food borne pathogens were obtained were considered unsatisfactory for human consumption.Presence of enteric bacteria in street foods indicates that the students of different Universities in Dhaka city might be at high risk of food borne disease</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 45-47</p> Nafisa Tanjia, Nahida Akhter, Ajoy Roy, Mir Shefaly Akhter, Muniruddin Ahmed, Sufia Islam ##submission.copyrightStatement## Sun, 08 Dec 2019 09:03:26 +0000 Study of Microbiological Quality of Fresh Juices Vended in Dhaka City <p>Fresh juices sold by the street vendors are rich in nutritional value and considered as popular drink in Dhaka city .They can be easily contaminated by pathogenic bacteria from unhygienic environment of food preparation area and serves as a potential source of food borne outbreaks. Freshly produced juices of papaya (n = 2), wood apple (n = 2), wood apple and papaya juice (1), lemon (n = 2), and sugarcane (n = 3) were examined for the total bacterial mload, coliforms, <em>Staphylococcus </em>spp., <em>Pseudomonas </em>spp., <em>Vibrio </em>spp., <em>Salmonella </em>spp., and <em>Shigella </em>spp. in this study. Total bacterial load in eight samples were within 0 to 10<sup>7</sup> cfu/ml, six samples exhibited the presence of staphylococci within the range of 0 to 10<sup>5</sup> cfu/ml. Total coliforms were detected in six samples which ranged from 10<sup>4</sup> to 10<sup>5</sup> cfu/ ml. <em>Vibrio </em>spp., <em>Salmonella </em>spp., and <em>Shigella </em>spp. were isolated by enrichment and selective plating method. Eight samples demonstrated the presence of <em>Vibrio </em>spp. and none of them were positive for <em>Salmonella </em>spp. and <em>Shigella </em>spp. Antibiotic sensitivity patterns were determined against eight isolates using Erythromycin (15μg), Amoxicillin (10 μg), Gentamicin (10 μg), Vancomycin (30 μg), Ciprofloxacin (5 μg), Rifampicin (5 μg), Azithromycin (15 μg), Neomycin (10 μg) and Cefexime (5 μg). <em>Klebsiella </em>sp. (n = 1), <em>Vibrio </em>sp. (n = 2), <em>Enterobacter </em>sp. (n = 1), and <em>Proteus</em> sp. (n = 1) showed multi drug resistance in this study. Contamination of street vended juices pose risks to consumers health and requires adequate attention of appropriate authority.</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 49-53</p> Kayseri Afroz, Tahmina Shammi, Md Shahidul Kabir ##submission.copyrightStatement## Sun, 08 Dec 2019 09:03:37 +0000 Impact of temperature on the growth of Pseudomonas spp. (SUBP01), Bacillus spp. (SUBB01) and Salmonella spp. (SUBS01) and determination of the critical growth temperature <p>With a previous observation of the defensive response against elevated temperatures and nutrient variation in <em>Escherichia coli </em>in different culture media, present study further demonstrated the consequences of high temperature on the growth of <em>Pseudomonas </em>spp. (SUBP01) <em>Bacillus </em>spp. (SUBB01), and <em>Salmonella </em>spp. (SUBS01). Bacterial growth was measured through the enumeration of the viable and culturable cells on Luria-Bertani (LB) and nutrient agar (NA) plates up to 72 hours, microscopic experiments were conducted to monitor subsequent physiological changes, and finally the loss of culturability due to high temperature stress was further confirmed by the observation of growth incapability through spot tests. A slight reduction in the culturable cells of <em>Pseudomonas </em>spp. (SUBP01) was observed at 45°C after 24 to 72 hours of incubation in the LB media while no such inhibition of growth was noticed in the nutrient media. Notably, <em>Bacillus </em>spp. and <em>Salmonella </em>spp. remained uninfluenced up to 52°C in both media, suggestive of the existence of a stringent defense mechanism against heat shock in these bacterial cells. However, both <em>Bacillus </em>and <em>Salmonella </em>cells were found to lose their culturablility completely at 53°C, and hence the critical temperature were recorded to be 52°C both for <em>Bacillus </em>spp. (SUBB01) and <em>Salmonella </em>spp. (SUBS01) while 45°C for <em>Pseudomonas </em>spp. (SUBP01) cells. Interestingly, the recovery of cells was noticed upon supplementation of Mg2+ and ethylene diamine tetra acetic acid (EDTA) through the increase in the viable and culturable cells at heat stressed condition. Consequently, all 3 bacterial species were subjected to transient heat shock by temperature up-shifting from 37°C to 45°C and 30 °C to 47°C in order to justify the bacterial heat shock response in the phenotypic state, whereby <em>Pseudomonas </em>spp. (SUBP01) cells were found lose culturability by temperature up-shifting from 30°C to 47°C, while <em>Salmonella </em>spp. (SUBS01) and <em>Bacillus </em>spp. (SUBB01) cells remained uninfluenced</p> <p>Bangladesh J Microbiol, Volume 36 Number 1 June 2019, pp 55-62</p> Rashed Noor, Sowmitra Ranjan Chakraborty, Ifra Tun Nur, Md Sakil Munna, Anamika Chakraborty, Tasnuba Tabassum Proma, Nafisa Tabassum, Syeda Muntaka Maniha, Tasmin Tabassum, Tahsin Tabassum, Nazratun Nayeem Choudhury ##submission.copyrightStatement## Sun, 08 Dec 2019 09:03:47 +0000