Papers by Muhammad Morshed
To investigate the involvement of urease in Helicobacter pylori colonization in the nude mouse st... more To investigate the involvement of urease in Helicobacter pylori colonization in the nude mouse stomach by using a genetically defined urease-negative mutant. Through electroporation-mediated gene replacement, one of the urease genes of an H. pylori strain, CYP3401, was disrupted by insertion of a kanamycin-resistance determinant to construct a stable urease-negative mutant, HPT73. Southern analysis confirmed that gene replacement was achieved. The two isogenic strains were introduced into the stomachs of nude mice, and the number of H. pylori and the histological changes in the stomachs were investigated 1 or 4 weeks after the challenge. Gastritis was present in the CPY3401-challenged stomach, from which bacteria indistinguishable from CPY3401 were successfully recovered. In contrast, no gastritis was found in the HPT73-challenged stomach, and H. pylori was not recovered from these stomachs. H. pylori urease is essential for colonization of the nude mouse stomach.
Journal of Medical Entomology, Mar 1, 2004
The Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt, and Brenne... more The Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt, and Brenner, was discovered in blacklegged ticks, Ixodes scapularis Say at Turkey Point, Ontario, Canada. We report the Þrst isolation of B. burgdorferi from a vertebrate animal collected on mainland Ontario. During this 2-yr study, spirochetes were isolated from the white-footed mouse, Peromyscus leucopus RaÞnesque, and attached I. scapularis larvae. Similarly, isolates of B. burgdorferi were cultured from blacklegged tick adults, and conÞrmed positive with polymerase chain reaction by targeting OspA and rrf (5S)-rrl (23S) genes. Moreover, all isolates of B. burgdorferi from this area had complementary genetic structure, and the second primer set amplicons conÞrmed the Þrst primer set ampliÞcation products. These Þndings show an epicenter endemic for B. burgdorferi within an established population of I. scapularis at Turkey Point.
Journal of Epidemiology, 1997
Epidemiological reports reveal that H. pylon is distributed among all population in the world. Th... more Epidemiological reports reveal that H. pylon is distributed among all population in the world. The present cross-sectional study was undertaken to see the H. pylon seroprevalence rates among the asymptomatic adults, as yet reportedly no such data available in Bangladesh. Serum samples were collected from 181 consecutive subjects who attended at the health checkup centre of Bangladesh Institute of Diabetis, Endocrine and Metabolic Disorders (BIRDEM), Dhaka, during the period of August to November 1995 for medical check up. The mean age of these subjects was 30.33 years (range 20-44 yrs). Incidentally all were male and belonged to average socioeconomic class. H. pylori specific IgG antibody level was assayed by an enzyme immunoassay kit ElAgen (Clone system). Among the 181 subjects, 166 (92%) had H. pylori specific antibodies and 15 (8%) were seronegative. No significant difference (p<0.90) in seroprevalence rates was observed among different age groups. However, the results of higher seroprevalance rates of H. pylori infection in these asymptomatic adult population of Bangladesh are consistent with that of Africa and India.
Journal of Clinical Microbiology
Relevé des maladies transmissibles au Canada
Contexte : La maladie de Lyme est une zoonose émergente à transmission vectorielle d'importance c... more Contexte : La maladie de Lyme est une zoonose émergente à transmission vectorielle d'importance croissante au Canada en termes de santé publique. Dans le cadre de son mandat, le Canadian Lyme Disease Research Network (CLyDRN) a mis en place en 2019 une initiative de surveillance sentinelle au niveau pancanadien, le Réseau sentinelle canadien de la surveillance de la maladie de Lyme (ReSCaL). Objectifs : La création d'un réseau de surveillance sentinelle national permettant d'évaluer l'évolution du risque environnemental de la maladie de Lyme en temps réel dans chaque province. Méthodes : Une approche d'analyse décisionnelle multicritère (ADMC) a été utilisée pour la sélection des régions sentinelles. Dans chaque région sentinelle, un protocole d'échantillonnage systématique par méthode de la flanelle a été réalisé dans des sites d'échantillonnage sélectionnés. Les tiques collectées au cours de ces visites de surveillance active ont été identifiées par espèce, et seulement les tiques Ixodes spp. ont été testées pour détecter des agents pathogènes tels que Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, Babesia microti et le virus Powassan. Résultats : En 2019, un total de 567 tiques Ixodes spp. (I. scapularis [n = 550] I. pacificus [n = 10]; et I. angustus [n = 7]) ont été collectées dans sept provinces : en
Viruses
Background: Investigating antibody titers in individuals who have been both naturally infected wi... more Background: Investigating antibody titers in individuals who have been both naturally infected with SARS-CoV-2 and vaccinated can provide insight into antibody dynamics and correlates of protection over time. Methods: Human coronavirus (HCoV) IgG antibodies were measured longitudinally in a prospective cohort of qPCR-confirmed, COVID-19 recovered individuals (k = 57) in British Columbia pre- and post-vaccination. SARS-CoV-2 and endemic HCoV antibodies were measured in serum collected between Nov. 2020 and Sept. 2021 (n = 341). Primary analysis used a linear mixed-effects model to understand the effect of single dose vaccination on antibody concentrations adjusting for biological sex, age, time from infection and vaccination. Secondary analysis investigated the cumulative incidence of high SARS-CoV-2 anti-spike IgG seroreactivity equal to or greater than 5.5 log10 AU/mL up to 105 days post-vaccination. No re-infections were detected in vaccinated participants, post-vaccination by qPC...
Communications Medicine
Background Lyme disease is a tick-borne illness that causes an estimated 476,000 infections annua... more Background Lyme disease is a tick-borne illness that causes an estimated 476,000 infections annually in the United States. New diagnostic tests are urgently needed, as existing antibody-based assays lack sufficient sensitivity and specificity. Methods Here we perform transcriptome profiling by RNA sequencing (RNA-Seq), targeted RNA-Seq, and/or machine learning-based classification of 263 peripheral blood mononuclear cell samples from 218 subjects, including 94 early Lyme disease patients, 48 uninfected control subjects, and 57 patients with other infections (influenza, bacteremia, or tuberculosis). Differentially expressed genes among the 25,278 in the reference database are selected based on ≥1.5-fold change, ≤0.05 p value, and ≤0.001 false-discovery rate cutoffs. After gene selection using a k-nearest neighbor algorithm, the comparative performance of ten different classifier models is evaluated using machine learning. Results We identify a 31-gene Lyme disease classifier (LDC) pa...
Emerging Infectious Diseases
BC, Canada) after 3 days of chills, headache, nausea, weakness, and urinary frequency. Her medica... more BC, Canada) after 3 days of chills, headache, nausea, weakness, and urinary frequency. Her medical history included psoriasis and psoriatic arthritis; her medications included ixekizumab. Her vital signs were within reference limits. Initial blood test results were within reference ranges, apart from a mild increase in the monocyte level (0.9 × 10 9 cells/L, reference range 0.1-0.8 × 10 9 cells/L) and a high level of C-reactive protein (14.5 mg/L, reference value <7.5 mg/L). Chest radiograph showed no acute fi ndings. The patient, believed to have a urinary tract infection, was discharged and given a 7-day course of oral cefi xime. Four BacT/Alert blood culture bottles (bioMérieux, https://www.biomerieux-usa.com) (3 aerobic and 1 anaerobic) were collected in the emergency department. One aerobic blood culture bottle showed a positive result for Brucella sp. after 3.5 days of incubation. A laboratory technologist prepared a slide for Gram staining and subcultured a sample into medium in a biosafety
Supplemental material, Johnston_SupplementaryAppendix for Effectiveness of Latent TB Screening an... more Supplemental material, Johnston_SupplementaryAppendix for Effectiveness of Latent TB Screening and Treatment in People Initiating Dialysis in British Columbia, Canada by Kamila Romanowski, Caren Rose, Victoria J. Cook, Inna Sekirov, Muhammad Morshed, Ognjenka Djurdjev, Adeera Levin and James C. Johnston in Canadian Journal of Kidney Health and Disease
Journal of Veterinary Medical and One Health Research, 2020
Background: Anthrax is one of the most important endemic zoonotic diseases due to its negative im... more Background: Anthrax is one of the most important endemic zoonotic diseases due to its negative impact on the smallholder farmers associated with mortality in livestock and disease in humans in Bangladesh. Objective: The main objective of this investigation was to assess the extent of knowledge, awareness, attitude and practices addressing anthrax in animals and humans in the communities of Bangladesh Materials and Methods: A descriptive cross-sectional survey was conducted in the ‘anthrax belt’ Sirajgonj district where several anthrax outbreaks have been reported in both the livestock and humans. A total of 26 household were selected randomly for sampling from each of four villages during the period from August to December 2013. A total of 104 adult respondents participated in the questionnaire survey and the data were calculated by using the formula 4 pq/d2 and Chi-square test using software. Results: Result shows that 55.8% of the community respondents had knowledge of anthrax, wh...
doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by pee... more doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.
Microbiology Spectrum, 2021
SARS-CoV-2, the causal agent of COVID-19, has infected over 150 million people and led to 3.8 mil... more SARS-CoV-2, the causal agent of COVID-19, has infected over 150 million people and led to 3.8 million deaths worldwide. With the approval of several efficacious COVID-19 vaccines, methods to evaluate protective immune responses will be crucial for the understanding of long-term immunity in the rapidly growing vaccinated population.
Diseases of Aquatic Organisms, 2021
Cryptococcus gattii is a fungal pathogen that primarily affects the respiratory and nervous syste... more Cryptococcus gattii is a fungal pathogen that primarily affects the respiratory and nervous systems of humans and other animals. C. gattii emerged in temperate North America in 1999 as a multispecies outbreak of cryptococcosis in British Columbia (Canada) and Washington State and Oregon (USA), affecting humans, domestic animals, and wildlife. Here we describe the C. gattii epizootic in odontocetes. Cases of C. gattii were identified in 42 odontocetes in Washington and British Columbia between 1997 and 2016. Species affected included harbor porpoises Phocoena phocoena (n = 26), Dall’s porpoises Phocoenoides dalli (n = 14), and Pacific white-sided dolphins Lagenorhynchus obliquidens (n = 2). The probable index case was identified in an adult male Dall’s porpoise in 1997, 2 yr prior to the initial terrestrial outbreak. The spatiotemporal extent of the C. gattii epizootic was defined, and cases in odontocetes were found to be clustered around terrestrial C. gattii hotspots. Case-control...
Frontiers in Immunology, 2021
To date there is limited data on the immune profile and outcomes of solid organ transplant recipi... more To date there is limited data on the immune profile and outcomes of solid organ transplant recipients who encounter COVID-19 infection early post-transplant. Here we present a unique case where the kidney recipient’s transplant surgery coincided with a positive SARS-CoV-2 test and the patient subsequently developed symptomatic COVID-19 perioperatively. We performed comprehensive immunological monitoring of cellular, proteomic, and serological changes during the first 4 critical months post-infection. We showed that continuation of basiliximab induction and maintenance of triple immunosuppression did not significantly impair the host’s ability to mount a robust immune response against symptomatic COVID-19 infection diagnosed within the first week post-transplant.
Canadian Journal of Kidney Health and Disease, 2020
Background: People undergoing chronic dialysis are at an increased risk of active tuberculosis (T... more Background: People undergoing chronic dialysis are at an increased risk of active tuberculosis (TB). In 2012, the Canadian province of British Columbia began systematically screening people initiating dialysis for latent TB using interferon-gamma release assay (IGRA), and treating when appropriate. Objective: The objective of this study was to compare active TB rate in people who initiated dialysis and were screened using an IGRA compared with those not screened during the same period. Design: Retrospective cohort study. Setting: British Columbia (BC), a Canadian province of 5.0 million people with an active TB incidence of 5.1 per 100 000 population. Participants: All people in BC who initiated at least 90 days of dialysis between January 2012 and May 2017 were included in the study. People were excluded if they were <18 years of age or had a prior history of active TB diagnosis or treatment for latent TB. Methods: A retrospective cohort was created of British Columbians who ini...
Infection Control & Hospital Epidemiology, 2020
To the Editor-Hemodialysis units are challenging environments to implement infection prevention a... more To the Editor-Hemodialysis units are challenging environments to implement infection prevention and control (IPAC) recommendations for coronavirus disease 2019 (COVID-19). 1 The Centers for Diseases Control and Prevention (CDC) recommends airborne and contact precautions for patients with suspected or confirmed cases of COVID-19. 2 In contrast, the Public Health Agency of Canada has recommended droplet and contact precautions, only recommending airborne precautions for aerosol-generating medical procedures (AGMPs). 3 Both recommendations are difficult to implement in hemodialysis facilities, which are predominantly open, pod-based units with limited or no single rooms, but recommendations have been developed specifically for dialysis facilities to prevent severe acute respiratory coronavirus virus 2 (SARS-CoV-2) transmission. 4 We describe our experience following an exposure to a nocturnal hemodialysis cohort as a result of an AGMP in a patient subsequently confirmed to have coronavirus disease 2019 (COVID-19). Methods The study was conducted at a tertiary-care hospital in Vancouver, Canada. Nocturnal hemodialysis patients are routinely dialyzed in the same pod, which accommodates 12 patients. Laboratory testing for SARS-CoV-2 was conducted on the cobas 6800 (Roche Molecular Diagnostics, Pleasanton, CA), targeting the Orf-1a and envelope (E) genes. COVID-19 point-of-care serology testing (COVID-19 IgM/IgG antibody test, Artron, Burnaby, Canada) was performed at the provincial reference laboratory. According to institutional infection prevention and control policies, patients with symptoms consistent with COVID-19 are tested for SARS-CoV-2 with a nasopharyngeal swab. In our hemodialysis unit, patients' temperatures are assessed on arrival and discharge, and any patients with a temperature of ≥37°C are tested.
Prehospital and Disaster Medicine, 2000
Journal of Sol-Gel Science and Technology, 2017
Hybrid sol-gel materials have been extensively studied as viable alternatives to toxic chromate (... more Hybrid sol-gel materials have been extensively studied as viable alternatives to toxic chromate (VI)-based coatings for the corrosion protection of AA2024-T3 in the aerospace industry, due to the wide range of available chemistries they offer and the tremendous development potential of innovative functional coatings. However, so far, little work has been performed in identifying the effect of the employed chemistries on the structure and anticorrosion properties of the coatings. This work proposes to contribute to a better understanding of the relationship existing between the structure, morphology and anticorrosion properties of hybrid sol-gel coatings deposited on AA2024-T3 aluminium surfaces, the most widely used alloy in the aerospace industry. The sol-gels are prepared employing two hybrid precursors; an organosilane, 3-trimethoxysilylpropylmethacrylate, and a zirconium complex prepared from the chelation of zirconium n-propoxide, and methacrylic acid. The structure of the hybrid sol-gel formulation is modified by altering the concentration of the transition metal complex. The structure and morphology of the coatings are characterised by dynamic light scattering, fourier transform infrared spectroscopy, silicon nuclear magnetic resonance spectroscopy, differential scanning calorimetry, scanning electron microscopy, atomic-force microscopy and the anticorrosion barrier properties characterised by electrochemical impedance spectroscopy and neutral salt-spray. It is found that the transition metal concentration affected the morphology and structure, as well as the anticorrosion performances of the hybrid sol-gel coatings. A direct correlation between the morphology of the coatings and their final anticorrosion barrier properties is demonstrated, and the optimum material amongst this series is determined to be comprised of a concentration of between 20 and 30% of transition metal.
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Papers by Muhammad Morshed