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Background and objectives: Several types of Burkholderia pseudomallei antigens have been used to determine the antibody response in acute and asymptomatic cases. In the present study, we have detected immunoglobulin G (IgG) antibody to recombinant truncated flagellin antigen (RTFA) of B. pseudomallei in the sera of acute melioidosis cases and healthy individuals from melioidosis endemic areas of Bangladesh by indirect enzyme-linked immunosorbent assay (ELISA). In parallel, IgG antibody to sonicated whole cell antigen (SWCA) of B. pseudomallei was determined to compare with anti-RTFA antibody. Methodology: Serum samples from culture confirmed melioidosis cases and from healthy individuals aged 21 years and above residing in melioidosis endemic rural areas were included in the study. Serum IgG antibody to RTFA and SWCA of B. pseudomallei was determined by indirect ELISA. Results: Out of 8 culture confirmed acute melioidosis cases, 7 (87.5%) and 8 (100%) were positive for anti-B. pseudomallei IgG antibodies by RTFA and SWCA methods respectively. Among 361 healthy individuals, the rate of seropositivity by RTFA-ELISA was significantly less than that of SWCA-ELISA (16.1% versus 26.8%; p = 0.001). The mean optical density (OD) of RTFA-ELISA of positive cases was significantly less than that of SWCA-ELISA in both melioidosis and healthy individuals (0.79±0.11 versus 2.4±0.08, p = 0.0001; 0.67±0.01 versus 1.27±0.02, p = 0.0001). The sensitivity and specificity of RTFA-ELISA were 88.9% and 100% respectively. Conclusion: Findings of the study suggest that multiple or combination of antigens should be used to study the seroprevalence of B. pseudomalleiinfection in a community. Also, prospective study is necessary to find out the duration of persistence of antibodies to different antigenic components of B. pseudomallei after exposure. IMC J Med Sci 2020; 14(1): 010. EPub date: 31 May 2020 *Correspondence: J. Ashraful Haq, Department of Microbiology, Ibrahim Medical College, 1/A Ibrahim Sarani, Segunbagicha, Dhaka 1000, Bangladesh. Email: jahaq54@yahoo.com

Background: CagA IgG antibody in sera might indicate presence of virulent Helicobacter pylori in patients with peptic ulcer disease. Present study was performed to find out the prevalence of CagA IgG antibody in patients with peptic ulcer/erosion. Methods: Any case that had peptic ulcer/erosion, plus positive for rapid urease test (RUT) or H. pylori stool antigen (HpSAg) or serum anti-H. pylori IgG/IgA were included in the study and named as H. pylori positive case. H. pylori positive cases were tested for CagA IgG antibody. Anti-H. pylori IgG, IgA and CagA IgG antibodies were determined by enzyme-linked immunosorbent assay (ELISA) and stool antigen by rapid immunochromatographic test (ICT). Urease production in biopsy sample was detected by RUT. Results: Total 86 H. pylori positive patients were included in the study. Out of 86 patients, CagA IgG was positive in 34 (39.5%; 95% CI: 0.30,0.50) cases. CagA seropositivity rate in ulcer and erosion cases were 58.8% (95% CI: 0.36,0.78) and 34.8% (95% CI: 0.25,0.47) respectively. H. pylori stool antigen and IgA antibodies were positive in all (100%) CagA antibody positive ulcer cases while the rates were significantly less among the CagA antibody negative cases (42.8% and 28.6%; p

Morganella morganii, a gram negative, facultative anaerobic bacterium belonging to the Proteeae tribe of the Morganellaceae family, is an unusual opportunistic pathogen mainly responsible for nosocomial and urinary tract infections. While cattle have long been established as a source of a few zoonotic pathogens, no such data has been recorded for M. morganii despite its ubiquitous presence in nature and a number of animal hosts. In this study, draft genomes were produced of three M. morganii isolates from Bangladeshi cattle. The three isolates, named B2, B3 and B5, possessed an average genome size of 3.9 Mp, a GC% of ∼51% and pan and core genomes of 4637 and 3812 genes, respectively. All strains were bearers of the qnrD1 carrying plasmid Col3M and possessed roughly similar virulence profiles and prophage regions. The strains also carried genes that were unique when compared with other publicly available M. morganii genomes. Many of these genes belonged to metabolic pathways associated with adaptation to environmental stresses and were predicted in silico to be borne in genomic islands. The findings of this study expand on the current understanding of M. morganii’'s genomic nature and its adaptation in cattle.

Background and objectives: Leptospirosis is a zoonotic infection with worldwide distribution caused by the Leptospira species and predominant in the tropical and subtropical regions. Information on leptospirosis in Bangladesh is limited. The present study was designed to detect anti-leptospiral antibodies in human serum samples in Bangladeshi population by developing an in-house ELISA using recombinant LipL32 (rLipL32) antigen. The study was conducted from April 2014 to December 2014.Method: Healthy individuals from two rural areas and fever cases from one urban healthcare center were enrolled in the study. Rural health centers were located at Sonargoan and Bajitpur sub-district (Upozilla) of Narayaganj and Kishorganj districts. Sonargoan health center is located 26 km south-east and Bajitpur is located 71 km north-east of Dhaka city. About 1-2 ml of blood was collected with aseptic measure and serum was separated and stored at -200C until used. Anti-leptospiral IgG antibody was determined by recombinant LipL32 (rLipL32) antigen based indirect enzyme linked immunosorbent assay (ELISA). Seropositive cases were further confirmed by commercial Leptospira IgG ELISA.Results: The study included 250 febrile cases and 376 healthy individuals from urban and rural areas, respectively. Out of total 626 study population, anti-LipL32 specific IgG antibody was detected in 70 individuals (11.2%). The rate of positivity of anti-LipL32 antibody among the healthy individuals from rural area was 10.6% while the rate was 12.0% in urban febrile population. The rate of positivity in rural and urban population was not significantly (p>0.05) different. Among the urban population, the rate of seropositivity was 9.1% and 16.4% in 21- 40 yrs and above 40 years age group respectively while the rate was 7.2% and 14.0% in rural population respectively. Out of 70 seropositive cases detected by LipL32 ELISA, 65 (92.9%) were positive by commercial ELISA.Conclusion: The present study has revealed that leptospirosis is prevalent in Bangladesh and should be looked for in febrile and clinically suspected cases. The study has also demonstrated that rLipL32 protein may be used as a candidate antigen for the serodiagnosis of leptospirosis.IMC J Med Sci 2017; 11(2): 50-55

In bacteria, the translocation of proteins across the cytoplasmic membrane by the Sec machinery requires the ATPase SecA. SecA binds ribosomes and recognises nascent substrate proteins, but the molecular mechanism of nascent substrate recognition is unknown. We investigated the role of the C-terminal tail (CTT) of SecA in nascent polypeptide recognition. The CTT consists of a flexible linker (FLD) and a small metal-binding domain (MBD). Phylogenetic analysis and ribosome binding experiments indicated that the MBD interacts with 70S ribosomes. Disruption of the MBD only or the entire CTT had opposing effects on ribosome binding, substrate-protein binding, ATPase activity and in vivo function, suggesting that the CTT influences the conformation of SecA. Site-specific crosslinking indicated that F399 in SecA contacts ribosomal protein uL29, and binding to nascent chains disrupts this interaction. Structural studies provided insight into the CTT-mediated conformational changes in SecA. Our results suggest a mechanism for nascent substrate protein recognition.

SecA is an evolutionarily conserved and essential ATPase that is required for the translocation of a subset of proteins across the cytoplasmic membrane in bacteria. SecA can recognise proteins that are destined for translocation as they are still being synthesised in order to deliver them to the membrane-bound Sec machinery. However, the mechanism of cotranslational substrate recognition is not well defined. In E. coli, SecA contains a relatively long C-terminal tail (CTT), which consists of a small metal-binding domain (MBD) that is attached to the C-terminus of the catalytic core by a flexible linker (FLD). In this study, we investigated the role of the CTT in the interaction of SecA with the ribosome and nascent polypeptides. Previous work indicates that the CTT is required for interaction with the molecular chaperone SecB. However, phylogenetic analysis suggested that the CTT (and the MBD in particular) has an additional function. Binding experiments indicated that the CTT interacts with 70S ribosomes, and disruption of the entire CTT moderately reduced the affinity of SecA for ribosomes. However, disruption of the MBD alone significantly increased the affinity of SecA for ribosomes and inhibited the interaction of SecA with substrate protein, suggesting that the FLD affects the conformation of SecA. Photocrosslinking and mass spectrometry indicated that the FLD is bound at the site where SecA binds to substrate proteins. Structural analysis by x-ray crystallography and small-angle x-ray scattering (SAXS) provided insight into how the CTT influences the structure of SecA in solution. Finally, site-specific crosslinking experiments indicated that binding to nascent substrate protein affects the conformation of SecA. Taken together, our results suggest that the CTT regulates the ability of SecA to interact with substrate proteins.

Background and objectives: Several diagnostic assays are used for the detection of Helicobacter pylori infection in suspected peptic ulcer cases. H. pylori stool antigen test is a non-invasive method for the detection of active infection. The present study has evaluated the efficacy of rapid stool antigen test to diagnose H. pylori infection in patients with dyspepsia. Materials and methods: Adult patients with complains of dyspepsia attending the Department of Gastroenterology, Hepatobiliary and Pancreatic Diseases (GHPD) of BIRDEM hospital for endoscopy were included. Gastric biopsy, blood and stool samples were obtained from each participant after informed written consent. Rapid urease test (RUT), serum H. pylori immunoglobulin A (IgA) and IgG and rapid H. pylori stool antigen (HpSAg) tests were performed. Only stool samples were obtained from 31 neonates aged 1 to 30 days as negative control for HpSAg test. Results: A total of 91 adult patients with complain of dyspepsia were included in the study. Out of 91 cases, 17 (18.7%) and 74 (81.3%) had peptic ulcer and erosion respectively. HpSAg was positive in 63.7% cases compared to 42.9% and 62.6% respectively by RUT and IgA. The rate of HpSAg positivity was significantly higher (p

This study was designed for early detection of drug resistance in Category II failure tuberculosis (TB) patients and to introduce a simple method to detect multi-drug resistant Mycobacterium tuberculosis (M.TB) from direct sputum sample. Total one hundred Ziehl-Neelsen (Z-N) staining positive Category II failure TB patients were enrolled in this study. Culture and drug susceptibility was done by slide and conventional method, among which 90 samples were positive by slide culture and 87 samples were positive by conventional culture. Susceptibility test by slide method showed 85 (94.44%) resistance to one or more anti -TB drugs. Resistance to Isoniazide (INH), Rifampicin (RMP), Ofloxacin (OFX) and Kanamycin (KA) was 94.44%, 84.44%, 31.11% and 4.44% respectively. By this method 80% isolates were detected as Multi-drug resistant (MDR) M.TB and 4.44% isolates were detected as Extended drug resistant (XDR) M.TB. Susceptibility results by slide DST demonstrated good concordance with conventional DST methods. Statistical analysis showed that, Sensitivity of slide DST method was 98.8%. Susceptibility results were available much faster by slide DST method (12.5±0.5 days) compared to that by conventional DST (60.4±5.9 days). Rate of contamination was also much lower by slide DST method than conventional culture (0.18% Vs 3.25%). The present study reflected that the slide DST method could be applied as rapid diagnostic tool to detect drug resistance among Category II failure TB cases, which is essential for applying appropriate therapy.DOI: http://dx.doi.org/10.3329/bjmm.v5i2.16910 Bangladesh J Med Microbiol 2011; 05 (02): 6-10

Antinuclear antibody (ANA) is useful in the diagnosis of connective tissue disorder (CTD). Association of specific autoantibodies with the immunofluorescence pattern of ANA in CTD, noted in western literature has been considered as reference in all over the world. However, in Bangladesh no such research work or data correlating the autoantibodies and their ANA patterns is found. Objective of the study was to identify an association between immunofluorescence patterns of antinuclear antibody on HEp-2 cell and more specific antinuclear reactivities (e.g. anti-dsDNA and anti-extractable nuclear antigen) in the serum samples of CTD patients. Serum samples of 152 CTD patients (Systemic lupus erythematosus, Rhumatoid arthritis, Sjogren´s syndrome, Systemic sclerosis, Polymyositis, Mixed connective tissue disease) were diagnosed clinically, attending at Bangabandhu Sheikh Mujib Medical University (BSMMU) during the study period of January, 2010 to December, 2010. Samples were subjected for ANA testing by Indirect Immunofluorescence (IIF) on HEp-2 cell (ALPHADIA) in dilution of 1:40, anti-dsDNA by ELISA and anti- extractable nuclear antigen (anti-ENA) by Dot Immunoblot. Dot blot strips were tested for anti-Sm, anti-RNP, anti-SSA/Ro, anti-SSB/La, anti-Scl-70 and anti-Jo-1. Out of 152 patients 110 (72.3%) cases were ANA positive by IIF on HEp-2 cell. ANA positive sera exhibited four fluorescence patterns such as speckled (50.8%), peripheral (21.6%) ,homogenous (18.1%) and nucleolar pattern (9%). Peripheral pattern and homogenous pattern was predominantly associated with anti-dsDNA (p