Tomasz A. Łęski

United States Naval Research Laboratory

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David A. Stenger

Archer Daniels Midland (United States)

Chris R. Taitt

United States Naval Research Laboratory

Rashid Ansumana

Njala University

Umaru Bangura

Njala University

Gary J. Vora

Naval Research Laboratory Center for Bio/Molecular Science and Engineering

Kathryn H. Jacobsen

University of Richmond

Baochuan Lin

Naval Research Laboratory Center for Bio/Molecular Science and Engineering

Joseph M. Lamin

Njala University

Anthony P. Malanoski

United States Naval Research Laboratory

Joseph Lahai

United States Naval Research Laboratory

Cooperative Institutions

United States Naval Research Laboratory

Naval Medical Research Unit Six

Naval Medical Research Command

Naval Research Laboratory Center for Bio/Molecular Science and Engineering

Njala University

CHI Health Mercy Council Bluffs

Cooper Green Mercy Hospital

Walter Reed Army Institute of Research

Johns Hopkins University

Naval Health Research Center

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Gronkowce oporne na mupirocyne: epidemiologia i molekularne mechanizmy opornosci

Postępy Mikrobiologii - Advancements of Microbiology (1998)

Tomasz A. Łęski

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Citations (2)

Detection of qnrVC and rmtB genes from a multidrug-resistant Ralstonia pickettii wound infection isolate in Cambodia

International Journal of Antimicrobial Agents (2014)

Vireak Heang Boren Hout Michael G. Prouty Chonthida Supraprom Gavin W. Ford

Amplicon

Nick translation

Klenow fragment

Primer (cosmetics)

10.1016/j.ijantimicag.2014.04.003

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Citations (5)

Seroprevalence of hepatitis B surface antigen (HBsAg) in Bo, Sierra Leone, 2012–2013

BMC Research Notes (2018)

Rashid Ansumana Donald F. Dariano Kathryn H. Jacobsen Tomasz A. Łęski Joseph M. Lamin

The aim of this study was to determine the prevalence of hepatitis B surface antigen (HBsAg) among febrile individuals tested at Mercy Hospital Research Laboratory (MHRL) in Bo, Sierra Leone.A total of 860 febrile individuals ages 5 years and older were tested by MHRL between July 2012 and June 2013 with a Standard Diagnostics Bioline HBsAg rapid diagnostic test. The overall HBsAg prevalence rate was 13.7%, including a rate of 15.5% among males and 12.6% among females. The HBsAg rate did not differ by child or adult age group (p > 0.5). The prevalence rate in Bo was similar to the 11-15% HBsAg prevalence rates reported in the past decade from other studies across West Africa. Scaling up the infant hepatitis B vaccination program in Sierra Leone will be important for reducing the future burden of disease and premature death attributable to chronic viral hepatitis B disease.

Seroprevalence

Hepatitis B

10.1186/s13104-018-3218-8

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Sequence Variability and Geographic Distribution of Lassa Virus, Sierra Leone

Emerging infectious diseases (2015)

Tomasz A. Łęski Michael Stockelman Lina Moses Matthew Park David A. Stenger

Lassa virus (LASV) is endemic to parts of West Africa and causes highly fatal hemorrhagic fever. The multimammate rat (Mastomys natalensis) is the only known reservoir of LASV. Most human infections result from zoonotic transmission. The very diverse LASV genome has 4 major lineages associated with different geographic locations. We used reverse transcription PCR and resequencing microarrays to detect LASV in 41 of 214 samples from rodents captured at 8 locations in Sierra Leone. Phylogenetic analysis of partial sequences of nucleoprotein (NP), glycoprotein precursor (GPC), and polymerase (L) genes showed 5 separate clades within lineage IV of LASV in this country. The sequence diversity was higher than previously observed; mean diversity was 7.01% for nucleoprotein gene at the nucleotide level. These results may have major implications for designing diagnostic tests and therapeutic agents for LASV infections in Sierra Leone.

Lassa virus

Lassa fever

Nucleoprotein

Lineage (genetic)

Mastomys

Subtyping

10.3201/eid2104.141469

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Citations (49)

Rapid design and fielding of four diagnostic technologies in Sierra Leone, Thailand, Peru, and Australia: Successes and challenges faced introducing these biosensors

Sensing and Bio-Sensing Research (2018)

Shawn P. Mulvaney Lisa A. Fitzgerald Leila J. Hamdan Bradley R. Ringeisen Emily R. Petersen

Febrile illnesses are among the most common reasons for visits to hospitals and clinics worldwide. Since fevers can arise from a wide range of diseases, identifying the causative pathogen is essential not only for effective personal treatment but also for early detection of outbreaks. The Defense Threat Reduction Agency (DTRA) tasked a coalition of commercial, academic, and government researchers with moving diagnostic technology concepts from ideation to field use as rapidly as possible using scientifically sound evaluations. DTRA's 24 Month Challenge program examined >30 technologies before fielding four technologies on four continents. >10,000 in field test results were recorded. Here we discuss our tiered evaluation system to assess candidate technologies developed by commercial partners and the process of field testing those technologies at various front-line clinics in Sierra Leone, Thailand, Peru, and Australia. We discuss successes and challenges for introducing two multiplexed lateral flow immunoassay (LFI) tests that detect malaria, dengue fever, melioidosis, and the plague. Additionally we discuss the use of a LFI reader that assisted the interpretation of the assay, communicated results to a data cloud, and greatly facilitated reach-back support. Lastly, we discuss the concurrent field testing of a multiplexed PCR assay on the FilmArray platform, which had an assay pouch specially designed for the 24 Month Challenge. Either standard-of-care or gold-standard testing were run alongside our fielded technologies to benchmark their performance.

10.1016/j.sbsr.2018.06.003

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Citations (9)

Optical chromatography for biological separations

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2004)

Sean J. Hart Alex Terray Katherine L. Kuhn Jonathan Arnold Tomasz A. Łęski

Laser trapping has been used for the manipulation of a wide variety of microscopic inorganic, metallic, polymeric, and biological particles, including cells, bacteria, and viruses. A more recently developed technique, optical chromatography, uses a lightly focused laser beam introduced into a counter-propagating fluid containing the particles to be trapped. Particle trapping and separation occurs through a balance of fluid drag forces and optical forces. The optical pressure that the laser exerts on a particle depends in part on its size, shape, and refractive index (chemical composition). Particles with a larger refractive index experience greater optical pressure and hence move farther upstream. Particles move against the fluid flow until reaching an equilibrium position where the fluid and optical forces are balanced. This position in relation to the focal point is termed the retention distance. Several important samples of biological origin have been separated and studied, including bacterial cells, spores, and pollens. The utility and prospects for optical chromatography are greatly expanded and the stage is set for many other optical characterization applications.

Optical force

Particle (ecology)

Radiation Pressure

Pressure-gradient force

10.1117/12.557363

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Citations (9)

POINT-OF-NEED DIAGNOSTICS: BIOSURVEILLANCE WITH A DEVICE2CLOUD CAPABILITY IN SIERRA LEONE

BMJ Global Health (2017)

Rashid Ansumana Chris R. Taitt Joseph M. Lamin Kathryn H. Jacobsen Shawn P. Mulvaney

Background Infectious diseases contribute to a high burden of diseases globally. Surveillance using low-cost technology, combined with cutting edge platforms offers a path for understanding the disease ecology of locations of interest in resource-poor countries. Our goal was to pilot a bio surveillance system comprising of rapid lateral flow immunoassays, rapid PCR and a cloud database. Methods The study was carried out in Bo, Sierra Leone at the Mercy Hospital. We recruited 1570 subjects over a period of two years. Inclusion criteria for the study were being febrile, being at least five years of age, living within the city of Bo or its neighbouring villages and agreeing to participate in the study. The assays used included a DPP multiplex lateral flow assay for dengue, Burkholderia pseudomallei , Yersinia pestis , malaria Pf/Pan, a Film Array PCR platform with multiplex Biothreat and SASFI panels that together detect over 30 pathogen targets. We used a Deki Reader to upload lateral flow images to the cloud database. The Deki reader quantitates test results, such that scores at ≥1.75 are considered positive. A special computer program was designed to upload pdf images of PCR results to the cloud database. The cloud database was designed for automated quality assessment and remote monitoring. Results Preliminary results show that out of 1570 samples processed by DPP, 30(1.9%) were positive for Burkholderia, 41(2.6%) were positive for Dengue NS1 antigen, 22(1.4%) were positive for Yesinia pestis fraction 1 antigen, and 340(21.7%) were positive for malaria. When a cross-section of results obtained by eye was compared with results automatically detected by the D2C platform, there was 95.2% concordance between results obtained by eye and those obtained automatically by the Deki reader to the cloud database. Conclusions Active disease surveillance and the ability to remotely monitor activities in peripheral health units are critical needs in many poor countries. Our results provide additional perspectives on the twin problem of surveillance and remote quality assessment.

Yersinia pestis

Multiplex

Upload

10.1136/bmjgh-2016-000260.28

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Citations (2)

Clonal Structure of the Methicillin-ResistantStaphylococcus aureus(MRSA) Population in Poland: Revision and Update

Microbial Drug Resistance (2005)

Jolanta Krzysztoń-Russjan Joanna Empel Tomasz A. Łęski Marek Gniadkowski Waleria Hryniewicz

The clonal structure of the methicilin-resistant Staphylococcus aureus (MRSA) population in Poland has been analyzed in several reports since the mid-1990s. The present study was performed on 253 MRSA isolates (146 archival and 107 new isolates) recovered in 26 hospitals between 1990 and 2001. Whereas all isolates were typed by pulsed-field gel electrophoresis (PFGE) and the analysis of the ClaI::mecA and ClaI::Tn554 RFLP polymorphism, selected isolates were also subjected to multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) comparisons. Based on the PFGE data, 15 MRSA clones were discerned, seven of which were observed in multiple hospitals. Five of these were related to the pandemic Hungarian (MLST clonal complex, CC8), Iberian (CC8), Pediatric (CC5), Mexican (CC30), and Brazilian clones (CC8). MLST confirmed the earlier reports on the similarity of the Hungarian and Brazilian clones, and it revealed that one of the two remaining epidemic clones was related to the Hungarian/Brazilian, and the other— to the Berlin clones. A local strain from the Northeastern part of the country was found to be similar to a minor Greek clone. The MRSA clonal structure and the increasing complexity of the relationships between the genetic and phenotypic traits of this micro-organism in Poland has now been firmly established.

Multilocus sequence typing

SCCmec

Molecular Epidemiology

clone (Java method)

10.1089/mdr.2005.11.127

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Citations (18)

Zbiorowiska grzybów ektomykoryzowych modrzewia europejskiego na powierzchni proweniencyjnej w LZD Krynica w Beskidzie Sądeckim

Tomasz A. Łęski Maria Rudawska

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Tracking Antimicrobial Resistance Determinants in Diarrheal Pathogens: A Cross-Institutional Pilot Study

International Journal of Molecular Sciences (2020)

Chris R. Taitt Tomasz A. Łęski Michael G. Prouty Gavin W. Ford Vireak Heang

Infectious diarrhea affects over four billion individuals annually and causes over a million deaths each year. Though not typically prescribed for treatment of uncomplicated diarrheal disease, antimicrobials serve as a critical part of the armamentarium used to treat severe or persistent cases. Due to widespread over- and misuse of antimicrobials, there has been an alarming increase in global resistance, for which a standardized methodology for geographic surveillance would be highly beneficial. To demonstrate that a standardized methodology could be used to provide molecular surveillance of antimicrobial resistance (AMR) genes, we initiated a pilot study to test 130 diarrheal pathogens (Campylobacter spp., Escherichia coli, Salmonella, and Shigella spp.) from the USA, Peru, Egypt, Cambodia, and Kenya for the presence/absence of over 200 AMR determinants. We detected a total of 55 different determinants conferring resistance to ten different categories of antimicrobials: genes detected in ≥ 25 samples included blaTEM, tet(A), tet(B), mac(A), mac(B), aadA1/A2, strA, strB, sul1, sul2, qacEΔ1, cmr, and dfrA1. The number of determinants per strain ranged from none (several Campylobacter spp. strains) to sixteen, with isolates from Egypt harboring a wider variety and greater number of genes per isolate than other sites. Two samples harbored carbapenemase genes, blaOXA-48 or blaNDM. Genes conferring resistance to azithromycin (ere(A), mph(A)/mph(K), erm(B)), a first-line therapeutic for severe diarrhea, were detected in over 10% of all Enterobacteriaceae tested: these included >25% of the Enterobacteriaceae from Egypt and Kenya. Forty-six percent of the Egyptian Enterobacteriaceae harbored genes encoding CTX-M-1 or CTX-M-9 families of extended-spectrum β-lactamases. Overall, the data provide cross-comparable resistome information to establish regional trends in support of international surveillance activities and potentially guide geospatially informed medical care.

Diarrheal diseases

Resistome

Enterotoxigenic Escherichia coli

10.3390/ijms21165928

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Citations (10)