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Diagnostic Test Validity of Oxacillin Screen Agar for the Detection of Methicillin Resistant Staphylococcus aureus  [PDF]
Hafiza Sultana, Md. Abdullah Yusuf, Jogendra Nath Sarker, Md. Tofael Hossain Bhuiyan, Shirin Tarafder
Open Journal of Medical Microbiology (OJMM) , 2018, DOI: 10.4236/ojmm.2018.82003
Abstract: Background: Detection of Methicillin Resistant Staphylococcus aureus may vary in phenotypic and genotypic methods. Objective: The aim of this present study was to validate the oxacillin screen agar test for the detection of methicillin-resistant Staphylococcus aureus isolated from clinical specimens. Methodology: This cross-sectional study was planned to carry out in the Department of Microbiology and Immunology at Bangabandhu Sheikh Mujib Medical University, Dhaka from January, 2010 to December, 2010 for a period of one (01) year. Different clinical specimens were collected from the patients presented with infections at anybody sites. Isolation and identification of Staphylococcus aureus (S. aureus) were performed by staining, culture and biochemical tests. Oxacillin screen agar test was performed to detect the methicillin-resistant Staphylococcus aureus. PCR was performed for detection of the mecA gene for MRSA. Result: Out of the 22 suspected MRSA isolates 19 were mecA positive by PCR. The sensitivity and specificity of oxacillin screen agar were 100.0% (95% CI 82.3 to 100.0%) and 33.3% (95% CI 24.0 to 90.6%) respectively. The positive predictive value and negative predictive value of oxacillin screen agar test were 90.5% (95% CI 81.0 to 95.5%) and 100.0% (95% CI 20.6 to 100.0%) respectively. The accuracy of the oxacillin screen agar test was 90.9% (95% CI 71.7 to 96.3%). Conclusion: In conclusion oxacillin screen agar test has high sensitivity with low specificity for the detection of MRSA.
Pre-Extensively Drug Resistant Tuberculosis (Pre-XDR-TB) among Pulmonary Multidrug Resistant Tuberculosis (MDR-TB) Patients in Bangladesh  [PDF]
Tamanna Tasnim, Shirin Tarafder, Fatema Mohammad Alam, Humayun Sattar, S. M. Mostofa Kamal
Journal of Tuberculosis Research (JTR) , 2018, DOI: 10.4236/jtr.2018.63018
Abstract: Background & Objectives: Emergence of drug resistant Tuberculosis (TB) is a major obstacle in the TB control programme of Bangladesh. This study was carried out to detect pre-extensively drug resistant TB (pre-XDR-TB) cases among the multidrug resistant TB (MDR-TB) patients in Bangladesh, as the early detection of pre-XDR-TB can guide clinicians in the appropriate modification of MDR-TB treatment regimen with effective drugs to prevent treatment failure. Methodology: A total of 68 MDR-TB cases were enrolled in this study. Multiplex Real-time PCR was done to detect pre-XDR-TB cases directly from sputum samples of MDR-TB patients. Results: Out of 68 MDR-TB cases 11 (16.18%) cases were detected as pre-XDR-TB. The resistant profile of the 11 pre-XDR-TB revealed 9 (81.82%) cases of fluoroquinolone (FLQ) resistant pre-XDR-TB and 2 (18.18%) cases of injectable second line (ISL) agent resistant pre-XDR-TB. Out of 11 pre-XDR-TB cases 7 (63.64%) cases had history of taking treatment for MDR-TB regularly, 1 (9.09%) case had history of taking treatment for MDR-TB irregularly and 3 (27.27%) cases had no history of taking treatment for MDR-TB. Conclusion: This study encountered a high rate of pre-XDR-TB cases along with a significant number of primarily resistant bacilli which is of concern in the management of MDR-TB. It is evident that Bangladesh is in urgent need to device strategies for rapid and early detection of pre-XDR-TB in order to prevent treatment failure of MDR-TB cases and also to halt the progression of MDR-TB cases to extensively drug resistant TB (XDR-TB), which is not only difficult but also very expensive to treat.
gyrA Gene Mutation Conferring Phenotypic Cross-Resistance among Fluoroquinolones (Ofloxacin, Levofloxacin and Gatifloxacin) in Multidrug Resistant Mycobacterium tuberculosis Strains Isolated from Pulmonary MDR-TB Patients in Bangladesh  [PDF]
Tamanna Tasnim, Fatema Mohammad Alam, S. M. Ali Ahmed, Shirin Tarafder, S. M. Mostofa Kamal, Shamim Hossain
Journal of Tuberculosis Research (JTR) , 2018, DOI: 10.4236/jtr.2018.63021
Abstract: Background and objectives: Fluoroquinolones (FLQs) are an essential component of multidrug resistant-tuberculosis (MDR-TB) treatment regimen but unfortunately the emergence of FLQ resistant MDR-TB cases is challenging the current MDR-TB treatment regimen. FLQ resistance is mainly caused by gyrA gene mutation and phenotypic cross-resistance may occur among the different FLQs. A limited number of data exists regarding the cross-resistance phenomenon among FLQs and it appears that resistance to the present class representative FLQ, ofloxacin (OFX), may or may not correlate with complete cross-resistance to other FLQs. So the study was designed to observe if gyrA gene mutations confer to the phenotypic cross-resistance among FLQs [OFX, Levofloxacin (LFX) and Gatifloxacin (GFX)] tested. Methodology: Sputum samples from 68 diagnosed pulmonary MDR-TB cases were collected. All samples were subjected to Multiplex Real-time PCR for the detection of gyrA gene mutations and conventional culture on Lowenstein-Jensen (L-J) media followed by drug sensitivity testing (DST) of culture isolates (MDR-TB strains) by indirect proportion method for the detection of phenotypic resistance pattern to OFX, LFX and GFX. Results: Out of the 68 MDR-TB sputum samples 13 (19.11%) had MDR-TB bacilli with mutations in the gyrA gene and 11(16.18%) of the MDR-TB culture isolates were found to have resistance to FLQs by DST. The study observed that 11 MDR-TB samples with gyrA gene mutations showed complete phenotypic cross-resistance among OFX, LFX and GFX. Conclusion: This study found that mutation in the gyrA gene of the MDR-TB bacilli results in the complete cross-resistance among the FLQs (OFX, LFX and GFX) tested. It is therefore of utmost importance to carry out the base line resistance and cross-resistance tests for the individual FLQs prior to initiating the treatment of MDR-TB cases in Bangladesh for successful clinical outcomes.
Antibiogram of Extended-Spectrum β-Lactamase (ESBL) Producing Escherichia coli  [PDF]
Jogendra Nath Sarker, Sarker Mohammed Ali Ahmed, Hafiza Sultana, Shaheda Anwar, Shirin Tarafder, Ahmed Abu Saleh
Open Journal of Medical Microbiology (OJMM) , 2019, DOI: 10.4236/ojmm.2019.92006
Abstract: Background: Extended-spectrum β-lactamases (ESBLs) are enzymes capable of hydrolyzing extended-spectrum cephalosporins, penicillins and monobactams but inactive against cephamycins and carbapenems. The ESBL-producing organisms are a breed of multidrug-resistant pathogens. Objectives: This study was aimed to determine the susceptibility pattern of ESBL-producing Escherichia coli to ciprofloxacin, amikacin and imipenem. Methods: A total of 75 ESBL-producing E. coli, were obtained from the tertiary care hospitals of Bangladesh and were studied for susceptibility pattern from October, 2010 to December, 2011. These isolates were identified by double disc synergy test (DDST) and were confirmed phenotypically as ESBL-producer by phenotypic confirmatory disc diffusion test (PCDDT). Minimum inhibitory concentrations (MICs) of ciprofloxacin, amikacin and imipenem among ESBL-producing E. coli were determined using agar dilution method. Results: Out of 75 DDST positive ESBL-producing E. coli, 71 (94.67%) were also positive by PCDDT. All ESBL-producing E. coli, were susceptible to imipenem. About 92.95% ESBL-producing E. coli were susceptible to amikacin but only 14.08% were susceptible to ciprofloxacin. Conclusion: In this study, ESBL-producing E. coli, showed high resistance to ciprofloxacin. Imipenem and amikacin were most effective against ESBL positive strains.
Micelle Mediated Extraction of Iron and Its Determination in Geological, Geochemical, Hydrogeochemical, Biogeochemical and Process Solutions  [PDF]
Pranab Kumar Tarafder, Rabin Kumar Mondal
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.35046
Abstract: Iron irrespective of its valency states forms bluish 1:1 cationic, bluish-violet 1:3 neutral and purple 1:3 anionic complexes with 2,3-dihydroxynaphthalene, at pH 2 - 3, 4 - 5 and 8 - 10, respectively. The cationic bluish complex is highly insensitive and not extractable in organic solvents. Similarly, the bluish violet 1:3 neutral complex is of moderate sensitivity, and it is extractable in organic solvents with reduced sensitivity. The purple 1:3 anionic complex is as such not extractable in any organic solvents. However, in the surfactant medium of the cationic surfactant, cetyltrimethylammonium bromide it is extractable in organic solvents with enhanced sensitivity. The 1:3 anionic complex which is extractable in organic solvents as an ion associate in the presence of cetyltrimethyl ammonium bromide is chosen for application to Silicate rocks, Minerals, Soils, Stream sediments, Concentrates, Tobacco leaves, Cigarettes and Waters, for accurate and sensitive determination of iron owing to facile extraction of iron, enhanced sensitivity high selectivity and better reproducibility of results. The present paper describes a systematic study on the development of an extraction spectrophotometric method for the determination of iron in samples of diverse matrices.
Electronic and Structural Properties of Li3AlP2 and Li3AlAs2 from First Principles  [PDF]
Mehrdad Dadsetani, Shirin Namjoo
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.29110
Abstract: A detailed analysis of the electronic and structural properties of the filled tetrahedral semiconductors Li3AlP2 and Li3AlAs2 has been performed, using the full potential linearized augmented plane wave method within the density functional theory. Experimental results about the structural properties, involves the positions of the elements Al and P(As). Since there were not any other efforts about the positions of the Li elements in these compounds, so to our knowledge there was no theoretical study about them till now. In the first step the interactional forces between atoms were minimized. The calculated internal coordinations of atoms agree well with the experimental results. Using these positions we obtained the equilibrium lattice constants, bulk modulus and their pressure derivative. In the second step the electronic properties of Li3AlP2 and Li3AlAs2 have been studied. The study of total and partial electronic DOS indicate the main contribution of DOS consists of P(As) 3p(4p) and P(As) 3s(4s) states. Our band structure calculation verifies that Li3AlP2 is an indirect gap semiconductor with a value of about 2.36 eV between valance band maximum occuring at H point and conduction band minimum occuring at Г point; though the difference between the direct (2.38 eV) and indirect (2.36 eV) is very small. We also found that Li3AlAs2 is a direct band gap (1.49 eV) in the center of BZ.
Optical conductivity in disordered alloys : an approach via the augmented space recursion
Kartick Tarafder,Abhijit Mookerjee
Physics , 2005, DOI: 10.1088/0953-8984/17/41/014
Abstract: We present here a calculation of the configuration averaged optical conductivity of random binary alloys CuAu and AgAu. Our formulation is based on the augmented space formalism proposed by Mookerjee [J. Phys. C : Solid State Phys. {\bf 6} 1340 (1973)] and the optical conductivity is obtained directly through a recursive procedure suggested by Viswanath and M\"uller ["The user friendly recursion method", Troisieme Cycle de la Physique, en Suisse Romande (1993)].
Numerical Solutions of a Class of Second Order Boundary Value Problems on Using Bernoulli Polynomials  [PDF]
Md. Shafiqul Islam, Afroza Shirin
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.29147
Abstract: The aim of this paper is to find the numerical solutions of the second order linear and nonlinear differential equations with Dirichlet, Neumann and Robin boundary conditions. We use the Bernoulli polynomials as linear combination to the approximate solutions of 2nd order boundary value problems. Here the Bernoulli polynomials over the interval [0,1] are chosen as trial functions so that care has been taken to satisfy the corresponding homogeneous form of the Dirichlet boundary conditions in the Galerkin weighted residual method. In addition to that the given differential equation over arbitrary finite domain [a,b] and the boundary conditions are converted into its equivalent form over the interval [0,1]. All the formulas are verified by considering numerical examples. The approximate solutions are compared with the exact solutions, and also with the solutions of the existing methods. A reliable good accuracy is obtained in all cases.
Investigating Language-Related Episodes during Mechanical and Meaningful Output Activities
Shirin Abadikhah
International Journal of English Linguistics , 2011, DOI: 10.5539/ijel.v1n2p281
Abstract: The present study examines how EFL learners consciously reflect on their language during a set of mechanical and meaningful output activities. Thirty-six Farsi learners of English negotiated on linguistic features and completed six activities over a period of six weeks. The transcripts from the learners’ interaction were analyzed for instances of language-related episodes (LREs), their principal focus on meaning or grammar and their nature and outcome. The results showed that (1) the meaningful output activities elicited significantly more LREs than did the mechanical output activities, (2) while approximately half of the LREs in the meaningful activities focused on lexis and meaning, the majority of LREs in the mechanical activities were directed towards grammatical forms and a small portion was focused on meaning, (3) the two output groups differed significantly in the continuous and correctly solved episodes. The study provides support on the effectiveness of collaborative output activities in pushing learners to verbalize their internal linguistic processing and focusing their attention on a wide range of linguistic features.
Book Review: Arshad Alam. Inside a madrasa. Knowledge, power and Islamic identity in India. New Delhi: Routledge. 2011.
Shirin Jahangir
Journal of International and Global Studies , 2012,
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