Mass, Spectroscopy, and Two-Neutron Decay of

The structure and decay of the most neutron-rich beryllium isotope, ^{16}Be, has been investigated following proton knockout from a high-energy ^{17}B beam. Two relatively narrow resonances were observed for the first time, with energies of 0.84(3) and 2.15(5) MeV above the two-neutron decay threshold and widths of 0.32(8) and 0.95(15) MeV, respectively. These were assigned to be the ground (J^{π}=0^{+}) and first excited (2^{+}) state, with E_{x}=1.31(6) MeV. The mass excess of ^{16}Be was thus deduced to be 56.93(13) MeV, some 0.5 MeV more bound than the only previous measurement. Both states were observed to decay by direct two-neutron emission. Calculations incorporating the evolution of the wave function during the decay as a genuine three-body process reproduced the principal characteristics of the neutron-neutron energy spectra for both levels, indicating that the ground state exhibits a strong spatially compact dineutron component, while the 2^{+} level presents a far more diffuse neutron-neutron distribution.

Prevalence of Virulence Genes in Acinetobacter baumannii Isolated from Clinical Samples in Mymensingh Medical College Hospital, Bangladesh.

Acinetobacter baumannii is an opportunistic bacterial pathogen that is the most important cause of hospital-acquired infections. The objective of this study was to evaluate the predominance and determination of virulence encoding genes in A. baumannii isolates. During this cross-sectional study period from February 2019 to March 2020 of 380 clinical samples including endotracheal aspirates (70), wound swab or pus (175), urine (70) and blood (65) analysed in inpatients admitted to the hospital in different unit like ICU, Surgery and Burn unit of Mymensingh Medical College Hospital. Out of 380 studied samples, 130(34.21%) strains were yielded growth. Among 130 isolates, Acinetobacter spp. was 49(37.69%). Totally, 39(79.59%) were Acinetobacter baumannii which was detected by molecular technique PCR. Further more, the determination of virulence genes csgA and fimH detected by PCR. Among two studied virulence genes, csgA (38.46%) was the most prevalent virulent genes associated with disease severity and co-morbidity of the patient in A. baumannii infections.

Study of Human Brucellosis among Patients with Pyrexia of Unknown Origin by Antibody Detection.

This study was performed to determine the seropositivity of human brucellosis among the patients suffering from pyrexia of unidentified origin. This cross-sectional study was performed at department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh from September 2018 to August 2019; among the patients of pyrexia of unknown origin visited inpatient and outpatient facility of department of Medicine and department of Paediatrics, Mymensingh Medical College Hospital (MMCH) in Mymensingh division of Bangladesh. A total of 400 serum samples were screened by Brucella-specific latex agglutination test to determine seropositivity. Seven percent (7.0%) (28/400) serum samples were found to be seropositive for brucellosis by detecting Brucella-specific antibody at a titer ≥1:160. Therefore, Brucella-specific latex agglutination test may be recommended as a screening test for human brucellosis in developing and underdeveloped countries.

Molecular Detection of MBL Encoding Genes in Acinetobacter baumannii strains Isolated from Various Samples at a Tertiary Care Hospital in Mymensingh.

MBL producing Acinetobacter baumannii is a major threat for therapeutic treatment of hospital acquired infections. The aim of this study was to determine the prevalence of metallo-ß-lactamase genes VIM, IMP & SIM genes amongst isolated A. baumannii. This cross sectional study conducted in the department of Microbiology Mymensingh Medical College from March 2019 to February 2020. 49 Acinetobacter spp. were isolated from different clinical samples including endotracheal aspirates, wound swab/pus, urine and blood. Among 380 clinical samples 130 organisms were isolated growth was 34.21%. Out of 130 isolated strains, 49(37.69%) were Acinetobacter spp identified by standard bacteriological method and resistance to different antibiotics was assessed with Kirby- Bauer Disc diffusion method. Among 49 Acinetobacter spp, 39(79.59%) were Acinetobacter baumannii which was identified by molecular method PCR directing OXA-51 like gene. Multiplex PCR was done to determine MBL genes existence VIM, IMP & SIM. Ceftriaxone (79.48%) showing higher resistance and colistin (12.82%) showing lower resistance. All the strains were sensitive to tigecycline. The distribution of MBLs genes such as VIM 20(51.28%), IMP 5(12.82%) and SIM 0 (0%). This study showed that high level of antibiotic resistance and VIM was the most prevalent MBL genes among A. baumannii highlighting the need for indigenous antibiotic usage plan & infection control measures to prevent the spread of these resistance genes.

Concurrent Infection of Orientia Tsutsugamushi with Rickettsia spp. Including Rickettsia felis in North Central Bangladesh.

Rickettsial diseases are one of the leading causes of treatable acute febrile illness in Asia pacific region. This cross-sectional descriptive study was conducted at Department of Microbiology, Mymensingh Medical College to diagnose scrub typhus by rapid Immunochromatographic Test (ICT) and Nested PCR followed by molecular identification of possible Rickettsial coinfection among suspected febrile patients in Mymensingh, Bangladesh from March 2019 to February 2020. Among the enrolled 402 patients, 89 samples (22.13%) were seropositive by Immunochromatographic Test (ICT) and 65 samples (16.16%) were positive for O. tsutsugamushi DNA by Nested PCR, targeting 47KDa gene. Therefore, 113/402 (28.10%) samples were positive for scrub typhus by PCR and/or ICT. All the scrub typhus positive samples were further subjected to Nested PCR targeting 17 KDa gene for identification of Rickettsial co-infection and 13/113 (11.50%) were documented as positive. Then 13 Rickettsial co-infected samples were undertaken to automate sequencing and all were genetically confirmed as Rickettsia felis. Findings of the study may help clinicians to expand their list of differential diagnoses for undifferentiated fever and detection of Rickettsial co-infection may guide them to prescribe effective antimicrobials.

Coexistence of ESBL and MBL-mediated resistance in Acinetobacter baumannii in a Tertiary Care Hospital, Bangladesh.

Antimicrobial resistance mediated by extended-spectrum beta-lactamases (ESBL), AmpC beta-lactamase and metallo-beta-lactamase (MBL) producing Acinetobacter species is an emerging problem worldwide. In this cross-sectional study total 341 specimens were collected over a period of one year from January 2017 to January 2018. Specimens were collected from ICU and Surgery unit of Mymensingh Medical College Hospital, Mymensingh, Bangladesh. Specimens were collected from ICU and Surgery Unit of Mymensingh Medical College Hospital, Mymensingh, Bangladesh. Samples were processed for culture by standard conventional methods and susceptibility testing and determined by Kirby Bauer disc diffusion method. Antibiotic discs and their strength were according to the CLSI 2017 guideline. Molecular study was done to detect the species by OXA-51 gene and drug resistance genes (IMP, VIM, NDM, TEM, SHV, CTX, SPM, SIM and GIM). Species identification was done by OXA-51 gene which is intrinsic to Acinetobacter baumannii. Among the 46 isolates, 36(78.26%) were positive for Oxa-51 gene, 16(34.8%) for TEM gene, 9(19.6%) for VIM gene, 3(6.5%) for NDM gene and 1(2.2%) for IMP gene. This study gives an alarming sign towards high prevalence of cephalosporin and carbapenem resistance due to production of extended spectrum beta-lactamases and metallo-betalactamases, respectively. Early detection, proper antibiotic policies, and compliance towards infection control practices are the best defenses against these organisms.

Socio-demographic and Clinico-epidemiological Study of Scrub Typhus in A Tertiary Care Hospital of Mymensingh, Bangladesh.

Scrub typhus is one of the leading causes of undifferentiated treatable febrile illness in Asia pacific region. It is grossly under diagnosed in many tropical countries of South Asia including Bangladesh, due to wide range of non-specific clinical presentations, low index of suspicion among clinicians, limited awareness and lack of accurate diagnostic facilities. This cross sectional observational study was conducted at department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh from March 2019 to February 2020 enrolling 113 diagnosed cases of scrub typhus by Immunochromatographic test (ICT) and / or Nested PCR to characterize the socio-demographic and clinico-epidemiological features of scrub typhus in Mymensingh area. Majority of the scrub typhus cases came from rural areas (63.83%) and there was a slight female predominance (52.21%). The young (32.74%) and the young-adult age group (28.31%) were mostly affected. Most of the scrub typhus cases were housewives (30.98%), followed by farmers (23.89%) and students (21.23%). All the enrolled cases presented with fever. Other findings were myalgia (76.10%), headache (56.63%), cough (30.97%), vomiting (12.38%) and Respiratory distress (9.73%). Typical eschar of scrub typhus was present only in 9(7.96%) cases and 4(3.53%) patients had rashes on their skin. Few cases (3.53%) had jaundice and 15.96% cases were anaemic. Oliguria (7.96%) and neck rigidity (1.76%) were also documented. Most of the Nested PCR positive scrub typhus cases were documented during late rainy season and beginning of winter months. Findings of the study may offer increased awareness about high burden of scrub typhus as well as heightened suspicion among clinicians for early diagnosis, timely treatment and prevention of complications.

Detection of Quinolone Resistance Pattern and Presence of qnr Genes in Human Salmonella Isolates at Mymensingh, Bangladesh.

Among the quinolones, fluoroquinolones are broad spectrum antimicrobial agents used for treating many clinical infections including Salmonellosis. Although high level of resistance to fluoroquinolones remains low in Salmonella but reduced susceptibility is increasing worldwide. Plasmid-mediated quinolone resistance (PMQR) of qnr type (qnrA, B and S) has been identified now a day in several enterobacterial species including Salmonella spp. This cross-sectional study was held at department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh from March 2019 to February 2020. This study was conducted to determine the current quinolone resistance pattern and to detect the presence of qnrA, qnrB and qnrS genes among Salmonella isolates. Antimicrobial susceptibility test of 36 Salmonella isolates were done by disc diffusion method. MIC of ciprofloxacin was detected by agar dilution method. Then amplification with specific primers of qnrA, qnrB and qnrS genes were performed for all Salmonella isolates. The present study observed 80.5% resistance to nalidixic acid, 33.3% to ciprofloxacin and 19.4% to ofloxacin by disc diffusion method. qnr A gene was detected in 2(5.5%) isolates, where as qnrS was detected in 5 (13.8%) isolates. None of the isolates was positive for qnrB gene. All the qnrA positive isolates showed resistance to Ciprofloxacin (MIC=128µg/ml) and Ofloxacin. In conclusion, presence of qnr genes in the study isolates is alarming, because, rapid dissemination might occur due to conjugative plasmid mediated horizontal transfer.

Reaction Mechanism and Selectivity Control of Si Compound ALE Based on Plasma Modification and F-Radical Exposure.

In this work, atomic layer etching (ALE) of Si compounds using H2 or N2 plasma modification followed by fluorine radical exposure is discussed. It is shown that the H2 plasma modification process promotes the selective etching of SiN, SiC, and SiCO versus SiO2. The N2 plasma modification, on the other hand, enables the selective etching of SiC and SiCO versus SiN and SiO2. The origin of the etching selectivity between different Si compounds is investigated using a combination of in situ SE and FTIR supported by several ex situ analysis techniques. It is shown that the formation of a hydrogen-rich layer after plasma modification is essential to enable the ALE process. The hydrogen-rich layer can be formed due to ion and radicals of the modification plasma (H2 plasma modification) or be a result of the reconfiguration of hydrogen that is already present in the film (N2 plasma modification). The obtained insights are expected to further enhance the etching selectivity of Si compound ALE processes. Furthermore, it is anticipated that the process can be extended to many other compound materials such as Ti and Hf, as well as enable selective etching between their oxides, carbides, and nitrides.

Bacteroides pyogenes isolated from appendiceal abscess in a patient without animal contact.

Bacteroides pyogenes is a member of the oral flora of cats and dogs. We report a case of B. pyogenes isolated from an appendiceal abscess in a patient without a history of animal contact. This species was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and sequencing of 16S rRNA, rpoB, gyrB and hsp60 genes.

Seropositivity of Human Brucellosis among Patients with Pyrexia of Unknown Origin on Both Risk and Non-Risk Group of Individuals and Molecular Detection by Real-time PCR.

Brucellosis is a zoonotic disease that is one of the important infectious causes of Pyrexia of Unknown Origin (PUO). The objective of the present study was to determine the seropositivity and molecular detection of human brucellosis among the patients with pyrexia of unknown origin on both risk and non-risk group of individuals in greater Mymensingh. A total of 400 blood samples were randomly collected from pyretic patients started from September 2018 to August 2019. Questionnaires were used to collect data on both risk and non-risk group of individuals. All samples were initially screened for anti-Brucella antibodies using the Brucella-specific latex agglutination test. For accurate investigation, seropositive as well as seronegative serum samples were tested by BCSP31 Brucella genus-specific TaqMan real-time PCR. Overall 32(8%) cases were positive out of 400 samples by Brucella-specific latex agglutination test and/or BCSP31 Brucella genus-specific real-time PCR. Brucella-specific latex agglutination test documented 7% (28/400) positivity for brucellosis. 22(5.5%) samples found Brucella genus-specific real-time PCR positive out of 400 samples. Most real-time PCR positive cases were found from sero-positive samples of risk group population (15/32). Sero-negative but real-time PCR positive cases also found only from risk group population (4/32). There were 10 seropositive cases where real-time PCR was negative. In addition to Brucella-specific latex agglutination test as a screening test, Brucella genus-specific real-time PCR was performed for confirmation and also to avoid unjustified costs, drug toxicity, and masking of other potentially dangerous diseases.

Detection of Biocide Resistance Genes (qacE and qacΔE1) in Pseudomonas spp Isolated from Patients with CSOM at Mymensingh Medical College Hospital, Bangladesh.

Biocides, including disinfectants and antiseptics, are used for a variety of topical and hard surface applications in health care facilities. Biocides play a significant role for preventing and controlling nosocomial infections. However, failures in the antimicrobial activities of biocides have been reported. The resistance mechanism to disinfectants is usually determined by genes which are related to resistance to quaternary ammonium compounds, namely, qacE, qacΔE1 that are found in Gram-negative bacteria. The aim of this study is to detect the prevalence of Biocides resistance genes, qacE and qacΔE1, in clinical isolates of Pseudomonas spp. It was carried out from March 2017 to July 2018 in the department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh. Samples were collected from Outpatient of ENT department, MMCH. In this study, 300 clinical samples of CSOM cases were tested by the PCR method. The present study shows detection of biocide resistance genes (qacE, qacΔE1) among 87 isolated Pseudomonas spp by uniplex PCR. Among 72 clinical isolates of Pseudomonas aeruginosa 67(93.05%) had the gene qacEΔ1 and 25(34.72%) had the gene qacE. In addition other 15 Pseudomonas spp 3(20%) isolates had the qacEΔ1 gene and 2(13.33%) isolates had the qacE gene. In this study there is a marked difference in detection of the qacEΔ1 gene between the MDR and non MDR P. aeruginosa isolates. The qacEΔ1 was identified in 50 of 54(92.59%) MDR isolates and 7 of 18(38.89%) non MDR strains respectively. While gene qacE was detect 25(46.29%) MDR isolates and did not show any qacEΔ1gene in non MDR isolates. This study shows that the genes, qacE, qacΔE1 are widespread among Pseudomonas aeruginosa, they are higher in MDR strains than non MDR strains.

Rapid Serologic and Molecular Diagnosis of Scrub Typhus among Suspected Febrile Patients Visiting Mymensingh Medical College Hospital.

Scrub typhus, caused by the bacterium- Orientia tsutsugamushi is one of the leading causes of undifferentiated treatable febrile illness in Asia pacific region. It is grossly under diagnosed in many tropical countries of South Asia including Bangladesh, due to wide range of non-specific clinical presentations, low index of suspicion among clinicians, limited awareness and lack of accurate diagnostic facilities. This cross-sectional descriptive study was conducted at Department of Microbiology, Mymensingh Medical College to diagnose scrub typhus by rapid Immunochromatographic test (ICT) as well as molecular detection of O. tsutsugamushi by Nested PCR and automated nucleotide sequencing among suspected febrile patients in Mymensingh, Bangladesh during 2019-20. Blood samples were collected from 402 febrile patients of suspected Rickettsial illness, referred from inpatient and outpatient departments of Medicine and Pediatrics, Mymensingh Medical College Hospital (MMCH). Among the enrolled 402 patients, 89 samples (22.13%) were seropositive by Immunochromatographic test (ICT) and 65 samples (16.16%) were positive for O. tsutsugamushi DNA by Nested PCR, targeting 47KDa gene. Therefore, 113/402 (28.10%) samples were positive for scrub typhus by PCR and/ or ICT. Highest number of patients was detected positive by nested PCR during the first 5-10 days of fever but only 2 cases were positive after 20 days. In case of ICT, highest positivity for only IgM (8.13%) and both antibodies (2.43%) were documented in first 5-10 days of fever, but IgG positivity was highest (41.66) in >20 days of fever. From 65 PCR positive samples, automated nucleotide sequencing was performed on 20 randomly selected samples and all were genetically confirmed to be O. tsutsugamushi.

Early and Rapid Detection of Typhoid Fever by Nested PCR in Blood.

Typhoid fever caused by Salmonella typhi is one of the major health problems in developing countries including Bangladesh. Still now blood culture is gold standard method for diagnosing typhoid fever, but this method is laborious, requires several days and detection rate is low. Failure of early laboratory diagnosis often leads to increased morbidity and mortality. This study was intended to apply a nested PCR in blood for early diagnosis of typhoid fever. In this cross sectional study blood samples were collected from 200 suspected typhoid fever patients attending Mymensingh Medical College Hospital, Bangladesh. Nested Polymerase Chain Reaction (n PCR) of flagellin gene was done in all the blood samples. At the same time all blood samples were subjected to culture by lytic centrifugation method. Culture positive isolates were identified as S. typhi by biochemical tests. Among the 200 blood samples, 57 (28.5%) were positive for S. typhi on nested PCR where as blood culture was positive for S. typhi in 16 (8%) samples. Among the 57 PCR positive samples, only 15 (26.3%) samples were culture positive for S. typhi and rest 42 (73.7%) were culture negative. So, in culture negative cases PCR can be used as a rapid diagnostic test for diagnosing typhoid fever. Considering time requirement, PCR takes one day, whereas blood culture takes 3 or more days to confirm diagnosis.

Prevalence of ESBL Encoding Genes in Acinetobacter baumannii Strains Isolated from Various Samples of a Tertiary Care Hospital in Mymensingh.

The aim of this study was to find the prevalence of ESBL genes among A. baumannii isolates. In this cross sectional study, 49 Acinetobacter spp. were isolated from various clinical samples from March 2019 to February 2020 conducted in the department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh. Clinical samples including endotracheal aspirates, wound swab/pus, urine and blood. A total of 380 samples were analyzed. Growth was obtained in 34.21% of the samples yielding 130 organisms. Out of 130 organisms, 49(37.69%) were Acinetobacter spp. Among 49 Acinetobacter spp, 39(79.59%) were Acinetobacter baumannii which was identified by PCR targeting OXA-51 like gene. Amplification of the ESBL encoding genes, namely CTX-M, TEM, SHV done by molecular technique PCR. The most antibacterial resistance was against ceftriaxone (79.48%) and lower resistance only showed in colistin (12.82%). All the isolates were sensitive to tigecycline. The distribution of ESBLs genes such as TEM 20(51.28%), CTX-M 16(41.02%) and SHV 0(0%). The high resistance to most of the antibiotics among the studied strains and also a high prevalence of TEM gene in A. baumannii strains found in our study gives alarming sign towards the treatment complexity of these strains.

Extensive genetic diversity with novel mutations in spike glycoprotein of severe acute respiratory syndrome coronavirus 2, Bangladesh in late 2020.

In Bangladesh, coronavirus disease 2019 (COVID-19) has been highly prevalent during late 2020, with nearly 500 000 confirmed cases. In the present study, the spike (S) protein of severe acute respiratory coronavirus 2 (SARS-CoV-2) circulating in Bangladesh was genetically investigated to elucidate the diversity of mutations and their prevalence. The nucleotide sequence of the S protein gene was determined for 15 SARS-CoV-2 samples collected from eight divisions in Bangladesh, and analysed for mutations compared with the reference strain (hCoV-19/Wuhan/WIV04/2019). All the SARS-CoV-2 S genes were assigned to B.1 lineage in G clade, and individual S proteins had 1-25 mutations causing amino acid substitution/deletion. A total of 133 mutations were detected in 15 samples, with D614G being present in all the samples; 53 were novel mutations as of January 2021. On the receptor-binding domain, 21 substitutions including ten novel mutations were identified. Other novel mutations were located on the N-terminal domain (S1 subunit) and dispersed sites in the S2 subunit, including two substitutions that remove potential N-glycosylation sites. A P681R substitution adjacent to the furin cleavage site was detected in one sample. All the mutations detected were located on positions that are functionally linked to host transition, antigenic drift, host surface receptor binding or antibody recognition sites, and viral oligomerization interfaces, which presumably related to viral transmission and pathogenic capacity.

Detection of Antimicrobial Resistance Pattern and ESBL Production among Clinical Isolates of Salmonella Species in Mymensingh, Bangladesh.

The occurrence of antimicrobial resistance in Salmonella enterica serovars (both typhoidal and non-typhoidal Salmonellae) is a major public health problem especially in developing countries, which have been associated with treatment failures. Therefore, the study was undertaken to determine the current antimicrobial resistance pattern and extended spectrum ß-lactamase (ESBL) production among clinical isolates of Salmonella spp. during 2019-2020 in Mymensingh, Bangladesh. In this cross sectional study, 36 Salmonella enterica isolates were obtained from blood and stool culture of suspected 200 enteric fever and 100 gastroenteritis patients attending at Mymensingh Medical College Hospital, Mymensingh, Bangladesh. Isolated Salmonella species were identified by biochemical tests and Polymerase Chain Reaction (PCR). Disk diffusion test was performed by modified Kirby Bauer method. Minimum Inhibitory Concentration (MIC) of ceftriaxone was detected by agar dilution method. Double disk synergy test was used as a screening test for ESBL production. PCR was done for detection of blaTEM, blaSHV and blaCTX-MU genes. The isolates showed 25% resistance to Ceftriaxone and 58.3% to Azithromycin. The highest sensitivity rates were 88.9% to Meropenem and 83.3% to Amikacin. Whereas 6(16.7%) isolates were Multi Drug Resistant (MDR). Eight (8) isolates were confirmed as ESBL producer by DDST. The marked increase in MIC was observed between 8->512µg/ml to ceftriaxone. blaTEM, blaSHV and blaCTX-MU genes were detected in 3, 5 and 8 isolates respectively. In conclusion, the current study observed, higher level of resistance to ceftriaxone and azithromycin. At the same times 22.2% isolates showed ESBL production, which is a cause for concern as it may lead to treatment failure. On the other hand the study also showed the re-emergence of chloramphenicol and Sulfamethoxazole-Trimethoprim sensitivity.

Quasifree Neutron Knockout Reaction Reveals a Small s-Orbital Component in the Borromean Nucleus

A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ^{17}B. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo.

Clonal diversity of Acinetobacter baumannii clinical isolates in Myanmar: identification of novel ST1407 harbouring blaNDM-1.

Recent Acinetobacter baumannii clinical isolates in a teaching hospital in Myanmar comprised three major sequence types (ST2, ST16 and ST23) and two sporadic STs, showing a high resistance rate to carbapenem associated with blaOXA-23 . The NDM-1 encoding gene was identified in only one isolate exhibiting novel ST1407 (a triple-locus variant of ST16).