Rashed Noor

Molecular Approaches for Detection of the Multi-Drug Resistant Tuberculosis (MDR-TB) in Bangladesh

The principal obstacles in the treatment of tuberculosis (TB) are delayed and inaccurate diagnosis which often leads to the onset of the drug resistant TB cases. To avail the appropriate treatment of the patients and to hinder the transmission of drug-resistant TB, accurate and rapid detection of resistant isolates is critical. Present study was designed to demonstrate the efficacy of molecular techniques inclusive of line probe assay (LPA) and GeneXpert MTB/RIF methods for the detection of multi-drug resistant (MDR) TB. Sputum samples from 300 different categories of treated and new TB cases were tested for the detection of possible mutation in the resistance specific genes (rpoB, inhA and katG) through Genotype MTBDRplus assay or LPA and GeneXpert MTB/RIF tests. Culture based conventional drug susceptibility test (DST) was also carried out to measure the efficacy of the molecular methods employed. Among 300 samples, 191 (63.7%) and 193 (64.3%) cases were found to be resistant against rifampicin in LPA and GeneXpert methods, respectively; while 189 (63%) cases of rifampicin resistance were detected by conventional DST methods. On the other hand, 196 (65.3%) and 191 (63.7%) isolates showed isoniazid resistance as detected by LPA and conventional drug susceptibility test (DST), respectively. Among the drug resistant isolates (collectively 198 in LPA and 193 in conventional DST), 189 (95.6%) and 187 (96.9%) were considered to be MDR as examined by LPA and conventional DST, respectively. Category-II and -IV patients encountered higher frequency of drug resistance compared to those from category-I and new cases. Considering the higher sensitivity, specificity and accuracy along with the required time to results significantly shorter, our study supports the adoption of LPA and GeneXpert assay as efficient tools in detecting drug resistant TB in Bangladesh.

Emerging diseases in Bangladesh: Current microbiological research perspective

Abstract Bangladesh has experienced a variety of diseases caused by natural dissemination of an array of pathogenic microorganisms into the environment. While cures for these diseases largely depend on the medication strategies of physicians, determining the reasons for disease persistence as well for the onset of reinfection is also essential. Routine diagnosis of common diseases usually means treatment with a range of appropriate medicines; however, failure of these medications because of the drug resistance of microorganisms accompanied by a lack of alertness about the etiology of diseases often leads to fatal results. The present review reports on emerging diseases in Bangladesh and focuses on associated microbiological research into ongoing diseases including enteric, urinary tract, and malarial complications. The viruses associated with acquired immunodeficiency syndrome and hepatitis are also discussed.

Mechanism to control the cell lysis and the cell survival strategy in stationary phase under heat stress.

An array of stress signals triggering the bacterial cellular stress response is well known in Escherichia coli and other bacteria. Heat stress is usually sensed through the misfolded outer membrane porin (OMP) precursors in the periplasm, resulting in the activation of σE (encoded by rpoE), which binds to RNA polymerase to start the transcription of genes required for responding against the heat stress signal. At the elevated temperatures, σE also serves as the transcription factor for σH (the main heat shock sigma factor, encoded by rpoH), which is involved in the expression of several genes whose products deal with the cytoplasmic unfolded proteins. Besides, oxidative stress in form of the reactive oxygen species (ROS) that accumulate due to heat stress, has been found to give rise to viable but non-culturable (VBNC) cells at the early stationary phase, which is in turn lysed by the σE-dependent process. Such lysis of the defective cells may generate nutrients for the remaining population to survive with the capacity of formation of colony forming units (CFUs). σH is also known to regulate the transcription of the major heat shock proteins (HSPs) required for heat shock response (HSR) resulting in cellular survival. Present review concentrated on the cellular survival against heat stress employing the harmonized impact of σE and σH regulons and the HSPs as well as their inter connectivity towards the maintenance of cellular survival.

PREVALENCE OF MICRO ORGANISMS IN COMMONLY USED COSMETICS SAMPLES IN DHAKA METROPOLIS

Present study attempted to identify and enumerate micro organisms spoiling commonly used cosmetics samples. Among 20 brands of total 6 categories of samples studied (soap, shampoo, lotion, face wash, cream and petroleum), almost all were found to be rigorously contaminated with total viable bacteria within a range of 10 3 – 10

Prevalence of vancomycin resistant Staphylococcus aureus (VRSA) in methicillin resistant S. aureus (MRSA) strains isolated from burn wound infections

Objectives: The increase in resistance of methicillin resistant Staphylococcus aureus (MRSA) strains to vancomycin has been perceived as a formidable threat in the therapeutic fields. The present study investigated the vancomycin resistance traits of MRSA isolates [vancomycin resistant S. aureus (VRSA)] collected from burn patients. Materials and Methods: Twenty-nine of 40 isolates of Staphylococcus spp. were identified as S. aureus which were further tested against 20 commercially available antibiotics to determine antibiotic susceptibility patterns. Results: Imipenem was the most potential antibiotic resulting in 90% sensitivity, followed by netilmicin, clindamycin, and nitrofurantoin (80% sensitivity). All isolates were found to be resistant to penicillin. Approximately 75% of them were found to be resistant to methicillin, oxacillin, azithromycin, cipro-floxacin, and tetracycline. Approximately 45% isolates exhibited resistance to amikacin, chloramphenicol, gentamycin, and tobramycin. Twenty-one of the 29 strains of S. aureus were MRSA, of which 11 were resistant to vancomycin when employing the disc diffusion method. However, when the broth micro-dilution procedure was used to measure the minimum inhibitory concentration (MIC) of vancomycin, eight isolates were resistant to vancomycin, six with an MIC of 32 μg/mL and two with an MIC of 64 μg/mL. Conclusion: A significant fraction of VRSA was found among MRSA strains in this study, revealing the necessity for new and effective drugs against MRSA.

Evaluation of the effectiveness of BACTEC MGIT 960 for the detection of mycobacteria in Bangladesh

OBJECTIVE Tuberculosis (TB) caused by Mycobacterium tuberculosis has been identified as a re-emerging infectious disease with public health importance globally. Exploitation of new laboratory techniques for precise identification of mycobacteria in clinical specimens is of great importance to improve the diagnosis as part of the global TB control efforts. METHODS The current study was conducted for the evaluation of BACTEC MGIT 960 method in comparison with Lowenstein-Jensen (LJ) culture and light emitting diode (LED) fluorescence microscopy for isolation of mycobacteria among TB suspects from Bangladesh. A total of 421 specimens were tested with these methods. RESULTS Among the tested samples, 3.6% (n=15) were LED fluorescence microscopy positive; while 18 (4.2%) and 45 (10.6%) were recovered from LJ and MGIT 960 culture. The relative positivity found through MGIT 960 system were 60% and 66.7% higher than that of LJ culture and LED fluorescence microscopy, respectively. Recovery rate of Mycobacterium tuberculosis complex ([MTC], 21 by MGIT and 16 by LJ culture) and non-tubercular mycobacteria ([NTM], 24 by MGIT and 2 by LJ culture) by MGIT 960 was 24% and 96% greater, respectively than LJ culture. Moreover, MGIT 960 was found to be highly sensitive (100%), specific (93.3%), accurate (93.6%) and a more rapid method in detecting mycobacteria when compared with LJ culture. CONCLUSION Extended recovery of NTM and MTC through MGIT 960 urged frequent application of this method to detect mycobacteria more effectively and rapidly.

Microbiological quality of pharmaceutical products in Bangladesh: current research perspective

Abstract Pharmaceutical industrialization in Bangladesh, both by multinational and local companies, has increased significantly in the last two decades. Most of the pharmaceutical products are found to be therapeutically competent to meet the demands of general population satisfactorily. However, complaints regarding the compromised quality of the products stored in markets are also reported very often. In order to ensure the overall drug user safety, the present review discussed the prime requirements for maintaining the desired microbiological quality of the commonly used pharmaceutical products in Bangladesh. Information relating to the prevalence of bacteria, fungi and the specific pathogens has been collected mostly from the recent researches conducted on an array of finished pharmaceutical medicaments. All data, achieved by means of traditional microbiological and biochemical analyses as described in the published papers cited in this review, have been further critically analyzed in context to the recommended microbial limits, user safety and the legislative aspects. Microbial contamination usually degrades the product quality as well as the product stability, which in turn creates treatment complications. Moreover, through microbial spoilage within the medicament, active drug constituents may be transformed to less potent or chemically inactive forms. Contamination by bacteria and fungi generally occur either from raw materials, manufacturing environment or at the storage stage which may hinder the consumer safety. This review article presented some valid evidences for microbial contamination in the pharmaceutical finished products in Bangladesh and discusses about possible remedies to improve the overall management of public health.

Microbiological Contamination and Anti-bacterial Traits of Common Oral Herbal Medicinal Products within Dhaka Metropolis

ABSTRACT Aims: Present study endeavored to examine the growth and survival of microorganisms within 6 categories of oral herbal medicines commonly used by the community within Dhaka metropolis. Methodology: Samples were analyzed for the presence of bacteria and fungi up to 14 days. The microbial analysis was conducted by conventional cultural and biochemical methods. The in vitro anti-bacterial activity of the medicines was also detected employing agar well diffusion method. Results: Initially all samples were found to be contaminated with total viable bacteria (10 2 -10 4 cfu/ml); however, the fungal and pathogenic growth was not observed. In course of time, the bacterial and fungal load increased up to 10 6 cfu/ml and 10 3 cfu/ml, respectively in most of the samples up to 14 days. The staphylococcal growth commenced after 48 hours in all samples and vigorously increased in two samples up to 10 5 cfu/ml. Two categories of samples were found to be populated with

Drug-resistant bacterial pathogens in milk and some milk products

Purpose – Current study was carried to detect the presence of pathogenic bacteria including the drug-resistant ones from milk and milk products. The paper aims to discuss these issues. Design/methodology/approach – Twenty-six raw milk samples from ten different areas, 28 pasteurized milk samples from 12 different companies and 26 yogurt samples from ten different sources in Dhaka city were microbiologically analyzed through cultural and biochemical identification of the isolates. Drug resistance trait was also determined by the Kirby-Bauer method on Muller-Hinton agar. Findings – Out of 80 samples studied, 74 were found to harbor pathogens within a range of 102-104 cfu/ml, including Escherichia coli, Salmonella spp., Staphylococcus aureus, and Vibrio spp. The study of antibiogram revealed that most of the isolates were resistant against most of the commonly used antibiotics. Research limitations/implications – Employment of only cultural/ biochemical tests excluding the molecular detection of virulence an...

Isolation of pathogenic microorganisms from burn patients admitted in Dhaka Medical College and Hospital and demonstration of their drug- resistance traits

Objective To isolate and quantify the microflora from the burn patients admitted in the Division of Plastic Surgery and Burns outdoor patients in Dhaka Medical College Hospital, Bangladesh.