Thomas Denagamage

Prof. Thomas Denagamage

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 April 2022 in Journal of Global Antimicrobial Resistance
Verified
Journal Article
Open access
MDMackenzie Dorr
Mackenzie Dorr
ASAryeh Silver
Aryeh Silver
DSDylan Smurlick
Dylan Smurlick
AAAnanta Arukha
Ananta Arukha
SKSubhashinie Kariyawasam
Subhashinie Kariyawasam
TDThomas Denagamage
Thomas Denagamage
This study aimed to sequence, assemble, and annotate three plasmids (two IncN and one IncI1) carrying the blaCTX-M-1 gene and assess their transferability rates between homologous and heterologous serovars and/or species of bacteria. First, the plasmids were sequenced, assembled, and annotated. They were then transferred from three donor strains (Escherichia coli/IncN, S. Heidelberg/IncN, and S. Heidelberg/IncI1) into nine recipient strains (S. Enteritidis, S. Heidelberg, S. Saintpaul, S. Cero, S. Infantis, S. Braenderup, E. coli 50, and E. coli 2010). The blaCTX-M-1 gene polymerase chain reaction (PCR), plasmid isolation, and antimicrobial susceptibility testing were used on the transconjugants to confirm the successful transfer of extended-spectrum beta lactamase (EBSL) plasmids into the recipient strains. Both IncN plasmids were 42,407 bp in size and showed >99.4% similarity to the S. Bredeney pET1.2-IncN (GenBank accession CP043224.1), whereas the IncI1 plasmid was 107,635 bp in size and demonstrated >99.9% similarity to the E. coli pCOV33 plasmid (GenBank accession MG649046.1). Successful plasmid transfer was observed between donor ​E. coli (IncN) and all recipient strains except for E. coli 50 and between donor S. Heidelberg (IncN) and all recipient strains. Successful plasmid transfer was also observed between S. Heidelberg (IncI1) and E. coli 50. Transfer of the blaCTX-M-1 encoding IncN and IncI1 plasmids via conjugation is possible and yet occurs at different frequencies depending on the donor strain of bacteria, with S. Heidelberg (IncN) having the highest donor-dependent transfer frequency, followed by E. coli 9079 (IncN) and S. Heidelberg (IncI1).

13 September 2022 in Frontiers in Veterinary Science
Verified
Journal Article
Open access
SGSimone D. Guerios
Simone D. Guerios
TPTenley R. Porcher
Tenley R. Porcher
GCGina Clemmer
Gina Clemmer
TDThomas Denagamage
Thomas Denagamage
Julie K. LevyJulie K. Levy
Julie K. Levy
The rise in subsidized spay-neuter access helped drive the euthanasia of shelter pets in the US from an estimated 13. 5 million in 1973 to 1.5 million in 2019. When the arrival of the COVID-19 pandemic triggered lockdowns beginning in March 2020, many veterinary providers suspended nonessential services such as routine spay-neuter surgeries. The purpose of this study was to determine the impact of the COVID-19 pandemic on the volume of spay-neuter procedures performed by spay-neuter clinics. A retrospective study of patient data from 212 spay-neuter clinics using Clinic HQ practice management software was conducted from January 2019 through December 2021. The clinics collectively performed 1,217,240 surgeries in the pre-COVID baseline year of 2019. A sharp decline in surgeries began in March 2020 (−22%) and reached a nadir in April 2020 (−80%). Surgeries began to increase in May 2020 (−39%), before plateauing in July 2020 (−6%) and remaining slightly below the 2019 baseline in most months through the end of 2021. Compared to 2019, total surgeries decreased 13% to 1,059,388 in 2020 and decreased 3% to 1,184,274 in 2021. In 2020, when clinic disruptions were highest, the impact of the surgery cutbacks varied by geographic region, species, age, and source of animals. Compared with 2019, in 2020 surgeries decreased 17% in the Midwest region, 15% in the Northeast and West, and 11% in the South. Surgeries were reduced 19% in dogs and 10% in cats. When grouped by age, surgeries were reduced by 18% in geriatrics, 14% in adults, and 11% in juveniles. Reductions were similar for females (−14%) and males (−12%) and similar for unowned/organization-owned animals (−14%) and privately owned animals (−12%). In total, 190,818 fewer surgeries were performed by the 212 studied clinics in the 24 months from January 2020 through December 2021 than would be expected had 2019 levels been maintained. If a similar pattern was experienced by other spay/neuter providers in the US, it would suggest there is a deficit of more than 2.7 million spay/neuter surgeries that animal welfare organizations have yet to address.

20 June 2017 in Avian Diseases
Verified
Journal Article
Closed access
TDThomas Denagamage
Thomas Denagamage
BJBhushan M. Jayarao
Bhushan M. Jayarao
EWEva Wallner-Pendleton
Eva Wallner-Pendleton
PPPaul H. Patterson
Paul H. Patterson
SKSubhashinie Kariyawasam
Subhashinie Kariyawasam
SUMMARY Consumption of shell eggs has been associated with Salmonella Enteritidis (SE) infections in humans in the United States. Because of this, the Pennsylvania Egg Quality Assurance Program (PEQAP) was developed and implemented in 1994. The PEQAP involves periodic flock testing and management practices to minimize SE contamination of shell eggs. Subsequently, the U.S. Food and Drug Administration (FDA) introduced a mandatory federal program in 2010 and 2012 for shell egg producers modeled closely after PEQAP to reduce the incidence and prevalence of SE during production, storage, and transport nationwide. In this study, a retrospective epidemiologic analysis was conducted by characterizing SE isolated from commercial layer environment samples and shell eggs submitted to the Animal Diagnostic Laboratory at The Pennsylvania State University using phage typing and pulsed-field gel electrophoresis (PFGE). The objective of this study was to determine the relatedness of SE isolates from hen house environmen... RESUMEN Estudio retrospectivo de Salmonella Enteritidis aislada de parvadas de aves de postura comerciales. El consumo de huevo se ha asociado con infecciones por Salmonella Enteritidis (SE) en seres humanos en los Estados Unidos. El Programa de Aseguramiento de la Calidad del huevo de Pensilvania (PEQAP) fue desarrollado e implementado en el año 1994. El PEQAP involucra pruebas periódicas de parvadas y prácticas de manejo para minimizar la contaminación por S. Enteritidis en el huevo. Posteriormente, la Administración de Alimentos y Fármacos de los Estados Unidos (FDA, por sus siglas en inglés) introdujo un programa federal obligatorio en 2010 y 2012 para los productores de huevo diseñado de manera muy similar al PEQAP para reducir la incidencia y prevalencia de S. Enteritidis durante la producción, almacenamiento y transporte a nivel nacional. En este estudio, se realizó un análisis epidemiológico retrospectivo mediante la caracterización de S. Enteritidis aisladas de muestras de ambiente de aves de pos...

25 October 2024 in Journal of Global Antimicrobial Resistance
Verified
Journal Article
Open access
YKYasir R. Khan
Yasir R. Khan
JHJorge A. Hernandez
Jorge A. Hernandez
SKSubhashinie Kariyawasam
Subhashinie Kariyawasam
GBGary David Butcher
Gary David Butcher
Daniel CzyzDaniel Czyz
Daniel Czyz
TDThomas Denagamage
Thomas Denagamage
This systematic review aimed to (i) determine the risk of antimicrobial resistance (AMR) development associated with antimicrobial use (AMU) and other exposure factors in broilers, and (ii) identify best management practices to mitigate preharvest AMR development of enteric bacteria alongside broiler production. Study selection criteria comprised the population, exposure or intervention, comparator, and outcome framework and included broiler (population), AMU or other management practices (exposure or intervention), organic or antibiotic-free production (comparator), and the presence of AMR-enteric bacteria/genes (outcome). Peer-reviewed primary research studies were searched in PubMed on 19 December 2022, and AGRICOLA, Embase, Scopus, and Web of Science on 10 February 2023. The risk of bias in studies was assessed using the modified ROBIS-E risk of bias assessment tool. The results were synthesised and presented narratively according to PRISMA 2020 guidelines. In total, 205/2699 studies were subjected to full-text review, with 15 included in the final synthesis. Enteric bacteria Escherichia coli, Salmonella, and Campylobacter exhibited AMR and multidrug resistance against several critically important antimicrobials (aminoglycoside, cephalosporin, chloramphenicol, macrolide, penicillin, quinolone, tetracycline, and sulfonamide) for human health. The risk of AMR development in bacteria was shown to be potentially higher with AMU in broiler production. Substandard farm management practices, poor biosecurity measures, and conventional production systems have also been associated with the dissemination of AMR in bacteria. Our findings indicate that AMU exposure is associated with considerably higher risk of AMR development in enteric bacteria. Antimicrobial stewardship, organic/antibiotic-free broiler production, good farm management practices, and high-level biosecurity measures are able to substantially mitigate preharvest AMR development in enteric bacteria. However, most of studies were cross-sectional, and therefore causal inference cannot be established.

7 January 2025 in Equine Veterinary Journal
Verified
Journal Article
Closed access
SCSierra Chanutin
Sierra Chanutin
ABAnje G. Bauck
Anje G. Bauck
JRJohn F. Roberts
John F. Roberts
TDThomas Denagamage
Thomas Denagamage
DFDavid E. Freeman
David E. Freeman

10 August 2023 in Toxics
Verified
Journal Article
Open access
PDF file
Adam W SternAdam W Stern
Adam W Stern
DRDaliana Roig
Daliana Roig
CVCourtney Valerio
Courtney Valerio
TDThomas Denagamage
Thomas Denagamage
Analysis of vitreous urea nitrogen (VUN) and creatinine (CREA) has been shown to be a useful indicator of azotemia in human postmortem examinations. Previous studies in cats, dogs, horses, and cattle have shown a good correlation between serum and postmortem ocular fluid for urea and creatinine. The aim of this study was to evaluate differences in VUN, CREA, and magnesium (MG) concentrations in vitreous humor collected postmortem from cats that presented with renal or post-renal disease and cats without renal or post-renal disease. Nine cats with renal or post-renal disease and twenty cats without renal or post-renal disease that underwent autopsy were used in this study. Collection of postmortem vitreous humor was performed, and vitreous samples were frozen at −80 °C for a minimum of 24 h prior to analysis using an in-clinic dry chemistry analyzer. Overall, there were statistically significant differences for VUN, CREA, and MG between cats with renal or post-renal disease and cats without renal or post-renal disease. Analysis of vitreous humor from cats suspected to have renal or post-renal disease can provide useful diagnostic information pertaining to renal function and issues in the urethra and urinary bladder. Future studies exploring postmortem vitreous chemistry in cats are warranted.