Biology Commons^™

Targeting Tgf-Β During Epithelial-To-Mesenchymal Progression As An Effective Therapy Against Colorectal Cancer, Joyce Fan

Undergraduate Research

Colorectal cancer is one of the most common cancers worldwide. Understanding the mechanisms of colorectal cancer progression is crucial for the development of effective therapeutics. Epithelial-to-mesenchymal transition is a hallmark feature of cancer and is defined as the loss of epithelial cell features, such as apical-basal polarity and high expression of cell adhesion molecules, and the development of mesenchymal features, such as lack of polarity and increased cell mobility. Epithelial-to-mesenchymal is essential for cell migration, proliferation, and tumor growth. Both the TGF-β and SMAD pathway are associated with colorectal cancer progression. TGF-β is crucial to the cellular mechanism of cell …

Old Vs. New: An Experiment On The Efficacy Of Complexity-Focused Reproductive Biology Lectures For Undergraduate Biology Students, Ive N. Muse, Shraddha Patel, Linda Fuselier

Undergraduate Research Events

Undergraduate reproductive biology courses are traditionally taught in a reductive manner, prioritizing a binary understanding of sex which oversimplifies reproductive behaviors and reproductive system development across diverse taxa. Although this binary approach to lessons on reproduction is intended to benefit students in learning foundational human reproductive concepts, it does not teach the most recent research in reproductive biology, which identifies reproductive variation as the norm. We designed and implemented a lesson on reproductive biology informed by the most current and accurate research and compared it to a traditionally taught biology lecture for first year majors. Students who received the experimental …

Advances In Methods For Trna Sequencing And Quantification, Nigam H. Padhiar, Upendra Katneni, Anton A. Komar, Yuri Motorin, Chava Kimchi-Sarfaty

Biological, Geological, and Environmental Faculty Publications

In the past decade tRNA sequencing (tRNA-seq) has attracted considerable attention as an important tool for the development of novel approaches to quantify highly modified tRNA species and to propel tRNA research aimed at understanding the cellular physiology and disease and development of tRNA-based therapeutics. Many methods are available to quantify tRNA abundance while accounting for modifications and tRNA charging/acylation. Advances in both library preparation methods and bioinformatic workflows have enabled developments in next-generation sequencing (NGS) workflows. Other approaches forgo NGS applications in favor of hybridization-based approaches. In this review we provide a brief comparative overview of various tRNA quantification …

Kif3a Tail Domain Phosphorylation Is Not Required For Ciliogenesis In Mouse Embryonic Fibroblasts, Ayoola Fasawe, Jessica M. Adams, Martin Engelke

Faculty Publications – Biological Sciences

Primary cilia are essential signaling organelles that protrude from most cells in the body. Heterodimeric kinesin-2 (KIF3A/KIF3B/KAP3) powers several intracellular transport processes, including intraflagellar transport (IFT), essential for ciliogenesis. A long-standing question is how a motor protein is differentially regulated for specific cargos. Since phosphorylation of the KIF3A tail domain was suggested to regulate the activity of kinesin-2 for ciliogenesis, similarly as for the cytosolic cargo N-Cadherin, we set out to map the phosphosites involved in this regulation. Using well-characterized Kif3a−/−; Kif3b−/− mouse embryonic fibroblasts, we performed ciliogenesis rescue assays with a library of phosphomimetic mutants comprising all …

Consequences Of Spatial Structure In Soil–Geomorphic Data On The Results Of Machine Learning Models, Daehyun Kim, Insang Song, Lorrayne Miralha, Daniel R. Hirmas, Ryan W. Mcewan, Tom G. Mueller, Pavel Samonil

Biology Faculty Publications

In this paper, we examined the degree to which inherent spatial structure in soil properties influences the outcomes of machine learning (ML) approaches to predicting soil spatial variability. We compared the performances of four ML algorithms (support vector machine, artificial neural network, random forest, and random forest for spatial data) against two non-ML algorithms (ordinary least squares regression and spatial filtering regression). None of the ML algorithms produced residuals that had lower mean values or were less autocorrelated over space compared with the non-ML approaches. We recommend the use of random forest when a soil variable of interest is weakly …

Meiosis In Budding Yeast, G. Valentin Borner, Andreas Hochwagen, Amy J. Macqueen

Biological, Geological, and Environmental Faculty Publications

Meiosis is a specialized cell division program that is essential for sexual reproduction. The two meiotic divisions reduce chromosome number by half, typically generating haploid genomes that are packaged into gametes. To achieve this ploidy reduction, meiosis relies on highly unusual chromosomal processes including the pairing of homologous chromosomes, assembly of the synaptonemal complex, programmed formation of DNA breaks followed by their processing into crossovers, and the segregation of homologous chromosomes during the first meiotic division. These processes are embedded in a carefully orchestrated cell differentiation program with multiple interdependencies between DNA metabolism, chromosome morphogenesis, and waves of gene expression …

Identification Of The Functional Domain Of The Dense Core Vesicle Biogenesis Factor Hid-1, Blake H. Hummer, Theodore Carter, Breanna L. Sellers, Jenna D. Triplett, Cedric S. Asensio

Biological Sciences: Faculty Scholarship

Large dense core vesicles (LDCVs) mediate the regulated release of neuropeptides and peptide hormones. HID-1 is a trans-Golgi network (TGN) localized peripheral membrane protein contributing to LDCV formation. There is no information about HID-1 structure or domain architecture, and thus it remains unknown how HID-1 binds to the TGN and performs its function. We report that the N-terminus of HID-1 mediates membrane binding through a myristoyl group with a polybasic amino acid patch but lacks specificity for the TGN. In addition, we show that the C-terminus serves as the functional domain. Indeed, this isolated domain, when tethered to the TGN, …

Transcriptional Pausing Factor M1bp Regulates Cellular Homeostasis By Suppressing Autophagy And Apoptosis In Drosophila Eye, Anuradha Venkatakrishnan Chimata, Hannah Darnell, Akanksha Raj, Madhuri Kango-Singh

Biology Faculty Publications

During organogenesis cellular homeostasis plays a crucial role in patterning and growth. The role of promoter proximal pausing of RNA polymerase II, which regulates transcription of several developmental genes by GAGA factor or Motif 1 Binding Protein (M1BP), has not been fully understood in cellular homeostasis. Earlier, we reported that M1BP, a functional homolog of ZKSCAN3, regulates wingless (wg) and caspase-dependent cell death (apoptosis) in the Drosophila eye. Further, blocking apoptosis does not fully rescue the M1BP^RNAi phenotype of reduced eye. Therefore, we looked for other possible mechanism(s). In a forward genetic screen, members of the Jun-amino-terminal-(NH2)-Kinase (JNK) pathway …

N-Acetyltransferase 9 Ameliorates Aβ42-Mediated Neurodegeneration In The Drosophila Eye, Prajakta Deshpande, Anuradha Venkatakrishnan Chimata, Emily E. Snider, Aditi Singh, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

Alzheimer’s disease (AD), a progressive neurodegenerative disorder, manifests as accumulation of amyloid-beta-42 (Aβ42) plaques and intracellular accumulation of neurofibrillary tangles (NFTs) that results in microtubule destabilization. Targeted expression of human Aβ42 (GMR > Aβ42) in developing Drosophila eye retinal neurons results in Aβ42 plaque(s) and mimics AD-like extensive neurodegeneration. However, there remains a gap in our understanding of the underlying mechanism(s) for Aβ42-mediated neurodegeneration. To address this gap in information, we conducted a forward genetic screen, and identified N-acetyltransferase 9 (Mnat9) as a genetic modifier of GMR > Aβ42 neurodegenerative phenotype. Mnat9 is known to stabilize microtubules by inhibiting c-Jun-N- …

The Art Of A Slugslayer: An Exploration Of The Process Of Extracting Radulae From Lehmannia Valentiana For The Purpose Of Viewing In The Scanning Electron Microscope, Elizabeth Gannon

Mahurin Honors College Capstone Experience/Thesis Projects

A radula is an anatomical structure found exclusively in mollusks that acts as both tongue and teeth in feeding. Its structure has been studied for more than a century, yet published methods for identifying, dissecting, and cleaning radulae for microscopy are almost unintelligible to anyone not already familiar with molluscan anatomy. The purpose of this project was to identify the best method of garden slug radula isolation and present it in a manner that anyone could understand and successfully use.

After identifying the location of the radula in the slug, the easiest means of removal proved to be simply regurgitating …

Effects Of Withania Somnifera On Zebrafish, Diyari Bekhtyar

Student Works

Withania somnifera (commonly known as Ashwagandha), is a plant in which its root powder is sold as a dietary supplement. It is being commonly used as an anti-anxiety supplement to combat stress. While the sale of Withania somnifera is widely accessible and available throughout the U.S., it is concerning that a number of teens and young adults are taking this supplement without consulting a physician. Previous studies and claims conclude that Withania somnifera has both neuroprotective and antiinflammatory properties in human neuronal cells. We have chosen to test Withania somnifera’s effects on early embryonic development using Danio rerio, zebrafish, as …

Surveillance And Stewardship: Where Infection Prevention And Antimicrobial Stewardship Intersect, Fred C. Tenover, Debra A. Goff

Biology Faculty Publications

Colonization with multidrug-resistant organisms (MDROs) is a risk factor for subsequent infection. Surveillance for MDROs, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, extended-spectrum beta-lactamase-producing Enterobacterales, and carbapenemase-producing organisms, is commonly conducted in hospitals to prevent spread of MDROs, in part to reduce the potential for additional infections. Although colonization is a risk factor for infection, data on colonization with various MDROs are often not considered when selecting anti-infective therapy. There are conflicting data on the strength of the positive and negative predictive values of the colonization test results to guide therapeutic strategies. Defining therapeutic strategies for patients with complicated or …

Thymic Stromal Lymphopoietin Participates In The Host Response To Intra-Amniotic Inflammation Leading To Preterm Labor And Birth, Tomi Kanninen, Li Tao, Roberto Romero, Yi Xu, Marcia Arenas-Hernandez, Jose Galaz, Zhenjie Liu, Derek Miller, Dustyn Levenson, Jonathan M. Greenberg, Jonathan Panzer, Justin Padron, Kevin Theis, Nardhy Gomez-Lopez Phd

Medical Student Research Symposium

Objective: To determine if bacteria (Ureaplasma parvum and Sneathia spp.) associated with intra-amniotic infection can trigger the induction of cytokine Thymic stromal lymphopoietin (TSLP) in human amnion epithelial cells (hAECs) in vitro.

Material or subjects: Amniotic fluid and chorioamniotic membrane (CAM) were collected from women with sPTL who delivered at term (n=30) or preterm without intra-amniotic inflammation (n=34), with sterile intra-amniotic inflammation (SIAI, n=27), or with intra-amniotic infection (IAI, n=17). Amnion epithelial cells (AECs), Ureaplasma parvum, and Sneathia spp. were also utilized.

Methods: The expression of TSLP, TSLPR, and IL-7Rα was evaluated in amniotic fluid or CAM by …

Myo19 Tethers Mitochondria To Endoplasmic Reticulum-Associated Actin To Promote Mitochondrial Fission, Stephen M. Coscia, Cameron P. Thompson, Qing Tang, Elana E. Baltrusaitis, Joseph A. Rhodenhiser, Omar A. Quintero, E. Michael Ostap, Melike Lakadamyali, Erika L. Holzbaur

Biology Faculty Publications

Mitochondrial homeostasis requires a dynamic balance of fission and fusion. The actin cytoskeleton promotes fission, and we found that the mitochondrially localized myosin, myosin 19 (Myo19), is integral to this process. Myo19 knockdown induced mitochondrial elongation, whereas Myo19 overexpression induced fragmentation. This mitochondrial fragmentation was blocked by a Myo19 mutation predicted to inhibit ATPase activity and strong actin binding but not by mutations predicted to affect the working stroke of the motor that preserve ATPase activity. Super-resolution imaging indicated a dispersed localization of Myo19 on mitochondria, which we found to be dependent on metaxins. These observations suggest that Myo19 acts …

Directed Carbapenemase Testing Is No Longer Just For Enterobacterales: Cost, Labor, And Workflow Assessment Of Expanding Carbapenemase Testing To Carbapenem-Resistant P. Aeruginosa, Fred C. Tenover, Christian M. Gill, Poonam Rajkotia, Amity L. Roberts, David P. Nicolau

Biology Faculty Publications

Molecular carbapenem-resistance testing, such as for the presence of carbapenemases genes, is commonly implemented for the detection of carbapenemase-producing Enterobacterales. Carbapenemase-producing P. aeruginosa is also associated with significant morbidity and mortality, although; prevalence may be underappreciated in the United States due to a lack of carbapenemase testing. The present study sought to compare hands-on time, cost and workflow implementation of carbapenemase gene testing in Enterobacterales and P. aeruginosa isolates versus sending out isolates to a public health laboratory (PHL) for testing to assess if in-house can provide actionable results. The time to carbapenemase gene results were compared. Differences in cost …

Methylene Blue Inhibits Cromakalim-Activated K+ Currents In Follicle-Enclosed Oocytes, Dmytro Isaev, Keun-Hang Susan Yang, Georg Petroianu, Dietrich Ernst Lorke, Murat Oz

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The effects of methylene blue (MB) on cromakalim-induced K⁺ currents were investigated in follicle-enclosed Xenopus oocytes. In concentrations ranging from 3–300 μM, MB inhibited K⁺ currents (IC₅₀: 22.4 μM) activated by cromakalim, which activates K_ATP channels. MB inhibited cromakalim-activated K⁺ currents in a noncompetitive and voltage-independent manner. The respective EC₅₀ and slope values for cromakalim-activation of K⁺ currents were 194 ± 21 µM and 0.91 for controls, and 206 ± 24 µM and 0.87 in the presence of 30 μM MB. The inhibition of cromakalim-induced K⁺ currents by MB was not …

Molecular Regulation Of The Salicylic Acid Hormone Pathway In Plants Under Changing Environmental Conditions, Christina A. M. Rossi, Eric J. R. Marchetta, Jong Hum Kim, Christian Castroverde

Biology Faculty Publications

Salicylic acid (SA) is a central plant hormone mediating immunity, growth, and development. Recently, studies have highlighted the sensitivity of the SA pathway to changing climatic factors and the plant microbiome. Here we summarize organizing principles and themes in the regulation of SA biosynthesis, signaling, and metabolism by changing abiotic/biotic environments, focusing on molecular nodes governing SA pathway vulnerability or resilience. We especially highlight advances in the thermosensitive mechanisms underpinning SA-mediated immunity, including differential regulation of key transcription factors (e.g., CAMTAs, CBP60g, SARD1, bHLH059), selective protein–protein interactions of the SA receptor NPR1, and dynamic phase separation of the recently identified …

Testing Ssa4:Ade3 Reporters For Mcs Screening, Karah Edmonds, Rebecca Adams

Science University Research Symposium (SURS)

In eukaryotic cells, after transcription, mRNA is escorted from the nucleus to the cytoplasm to be translated. This process, called mRNA export, is essential for gene expression. However, when the cell exists in stressful conditions, mRNA export becomes regulated, and only select transcripts, including the stress-responsive SSA4 mRNA, can be exported. This project aims to uncover the mechanism of selective SSA4 mRNA export by generating a reporter that enables phenotypically visible expression under stressful conditions. Specifically, the ADE3 ORF was placed under the regulatory sequence of SSA4, which was anticipated to induce a red color for colonies only following stress. …

A Pooling Strategy For Detecting Carbapenem Resistance Genes By The Xpert Carba-R Test In Rectal Swab Specimens, Fred C. Tenover, Peng Zhang, Qi Wang, Chaoe Zhou, Feifei Zhang, Xinghui Gao, Yi-Wei Tang, Hui Wang

Biology Faculty Publications

Rapid and accurate detection of carriers of carbapenemase-producing organisms (CPO) in hospitalized patients is critical for infection control and prevention. This study aimed to evaluate a pooling strategy for the detection of carbapenem resistance genes (CRG) in multiple specimens using the Xpert Carba-R test. Two rectal swabs each were collected from 415 unique patients. One swab was tested by Carba-R on the five specimen-pooled strategy. The other swab was tested individually by culture followed by DNA sequence analysis for CRG as the reference. At the first 5:1 pooling testing, 22 of 83 pools were positive, which yielded 34 positives from …

The Trichloroethylene Metabolite S-(1,2-Dichlorovinyl)-L-Cysteine Inhibits Lipopolysaccharide-Induced Inflammation Transcriptomic Pathways And Cytokine Secretion In A Macrophage Cell Model, Sean M. Harris, Kelly M. Bakulski, John Dou, Ethan Houskamp, Eleanor Scheeres, Emily Schellenboom, Olivia Harlow, Rita Loch-Caruso, Erica Boldenow

University Faculty Publications and Creative Works

Studies have shown that the trichloroethylene metabolite S-(1,2-dichlorovinyl)-l-cysteine (DCVC) inhibits cytokine secretion in pathogen stimulated fetal membrane tissue but little is known about the mechanism for these effects, including which cell types or transcriptomic pathways are impacted. Macrophages play a critical role in fetal membrane immune responses during infection. We tested the hypothesis that DCVC inhibits lipopolysaccharide (LPS) stimulated inflammation pathways in macrophage-like THP-1 cells. We treated THP-1 cells for 24 h then treated with 1, 5, or 10 μM DCVC for 24 h. After a 4 h incubation with lipopolysaccharide (LPS), we collected RNA and cell media. We performed …

Leaf Phenology And Freeze Tolerance Of The Invasive Tree Pyrus Calleryana (Roseaceae) And Potential Native Competitors, Margaret E. Maloney, Abby Hay, Eric B. Borth, Ryan W. Mcewan

Biology Faculty Publications

Pyrus calleryana is one of the most problematic invasive species in the eastern United States. The mechanisms that enable Py. calleryana to establish and outcompete native plants are not fully understood but likely include a profile of advantageous traits. Extended leaf phenology is a characteristic noted in many woody invasive plants. Leaf phenology of Py. calleryana and two native woody species, Populus deltoides and Platanus occidentalis, was observed in natural areas near Dayton, OH from December 2019 to November 2020. A frost event in May also gave us the serendipitous opportunity to assess frost tolerance of these species. We …

Mechanisms Of Carbapenemase-Mediated Resistance Among High-Risk Pseudomonas Aeruginosa Lineages In Peru, Isabella A. Tickler, Juan Carlos Gomez De La Torre, Luis Alvarado, Anne E. Obradovich, Fred C. Tenover

Biology Faculty Publications

Objectives: Pseudomonas aeruginosa is one of the leading causes of healthcare-associated infections globally. High-risk carbapenemase-encoding P. aeruginosa clones are disseminating in many regions. The aim of this study was to learn more about the lineages and mechanisms of resistance of P. aeruginosa circulating in Peru.

Methods: A total of 141 carbapenemase-producing isolates recovered from hospitalized and ambulatory patients in Lima were sequenced and analyzed to infer their lineages through whole-genome sequence typing (wgST) and to identify their antimicrobial resistance genes.

Results: wgST identified nine sequence types (STs); ST111 and ST357 were the most frequently encountered (44.0% and 38.3%, respectively), followed …

Increasing The Resilience Of Plant Immunity To A Warming Climate, Jong Hum Kim, Christian Castroverde, Shuai Huang, Chao Li, Richard Hilleary, Adam Seroka, Reza Sohrabi, Diana Medina-Yerena, Bethany Huot, Jie Wang, Sharon Marr, Mary Wildermuth, Tao Chen, John Macmicking, Sheng Yang He

Biology Faculty Publications

Extreme weather conditions associated with climate change affect many aspects of plant and animal life, including the response to infectious diseases. Production of salicylic acid (SA), a central plant defence hormone, is particularly vulnerable to suppression by short periods of hot weather above the normal plant growth temperature range via an unknown mechanism. Here we show that suppression of SA production in Arabidopsis thaliana at 28 °C is independent of PHYTOCHROME B (phyB) and EARLY FLOWERING 3 (ELF3), which regulate thermo-responsive plant growth and development. Instead, we found that formation of GUANYLATE BINDING PROTEIN-LIKE 3 (GBPL3) defence-activated biomolecular condensates (GDACs) …

Ciliate Endosymbiont Imaging Methodology, Aidan Boving, Roxanne Beinart

Senior Honors Projects

Ciliates, a phylum of diverse microbial eukaryotes, are found in a wide range of environments, including anoxia. Anaerobic ciliates host intracellular methanogenic archaea – a unique type of symbiosis. Despite their importance, anaerobic ciliates and their symbiotic relationships remain understudied. Included in this is the ability to image and quantify the intracellular methanogenic symbionts in a precise, timely and replicable procedure. This project aimed to improve the current fluorescence microscopy methodology used for endosymbiont quantification. The proposed method is intended for use with the Opera Phenix, a high throughput spinning disk confocal microscope which can count large amounts of individual …

The Central Dogma: Gene Expression, Ayisha Sookdeo

Open Educational Resources

In this lesson plan, students will learn the basic structure and function of DNA and RNA. They will also learn the process of gene expression. Finally, students will learn about the scientific contributor, Ernest Everest Just, and his contributions to the field of Biology.

Developing An Electroporation Method For Transforming Streptomyces Nymphaeiformis, Heather Knott, Stephen Baron

Honors Projects

Streptomyces species are notoriously difficult to transform. Streptomyces nymphaeiformis is no different, so a method of electroporation was used to attempt to transform the cells. Multiple growth stages were used in order to alter the degree of development of the cell wall. The procedure did not kill the cells, but the cells were not transformed. Due to the lack of transformation with S. nymphaeiformis, transformation was attempted on two other Streptomyces strains, S. lividans and S. coelicolor. Neither was successfully transformed to thiostrepton (tsr) resistance, nor did they grow on a plate lacking thiostrepton. One possibility for the …

The Sglt2 Inhibitor Canagliflozin Reduces Androgen Receptor Expression And Nuclear Localization Of Beta-Catenin In Human Prostate Cancer Cells, Kalkidan Bekele, Tunde Smith, Lamonica Stewart

Student Research

Drugs that inhibit the protein sodium-glucose cotransporter-2 (SGLT2) are commonly used in the United States to treat type 2 diabetes. Recent studies suggest that SGLT2 inhibitors reduce growth of lung, liver, and breast cancer cells in vitro. Therefore, administration of SGLT2 inhibitors may also limit the growth of malignant tumors. Previous work from our laboratory has shown that one SGLT2 inhibitor, canagliflozin, reduces the proliferation of C4-2B cells, a castration-resistant human prostate cancer cell line. Concentrations of canagliflozin that reduce proliferation also lower levels of the androgen receptor (AR), a protein known to promote growth of prostate cancers. The goal …

Characterization Of SccMec Instability In Methicillin-Resistant Staphylococcus Aureus Affecting Adjacent Chromosomal Regions, Including The Gene For Staphylococcal Protein A (Spa), Isabella A. Tickler, Fred C. Tenover, C. R. Scharn, R. V. Goering

Biology Faculty Publications

Staphylococcal cassette chromosome mec (SCCmec) represents a sequence of clear clinical and diagnostic importance in staphylococci. At a minimum the chromosomal cassette contains the mecA gene encoding PBP2a but frequently also includes additional antibiotic resistance genes (e.g., ermA and aadC; macrolide and aminoglycoside resistance, respectively). Certain regions within SCCmec elements are hot spots for sequence instability due to cassette-specific recombinases and a variety of internal mobile elements. SCCmec changes may affect not only cassette stability but the integrity of adjacent chromosomal sequences (e.g., the staphylococcal protein A gene; spa). We investigated SCCmec stability …

Salicylic Acid And N-Hydroxypipecolic Acid At The Fulcrum Of The Plant Immunity-Growth Equilibrium, Alyssa Shields, Vanessa Shivnauth, Christian Danve M. Castroverde

Biology Faculty Publications

Salicylic acid (SA) and N-hydroxypipecolic acid (NHP) are two central plant immune signals involved in both resistance at local sites of pathogen infection (basal resistance) and at distal uninfected sites after primary infection (systemic acquired resistance). Major discoveries and advances have led to deeper understanding of their biosynthesis and signaling during plant defense responses. In addition to their well-defined roles in immunity, recent research is emerging on their direct mechanistic impacts on plant growth and development. In this review, we will first provide an overview of how SA and NHP regulate local and systemic immune responses in plants. We …

Carbapenemase-Producing Pseudomonas Aeruginosa – An Emerging Challenge, Fred C. Tenover, David P. Nicolau, Christian M. Gill

Biology Faculty Publications

Carbapenem-resistant Pseudomonas aeruginosa (CR-PA) is a major healthcare-associated pathogen worldwide. In the United States, 10–30% of P. aeruginosa isolates are carbapenem-resistant, while globally the percentage varies considerably. A subset of carbapenem-resistant P. aeruginosa isolates harbour carbapenemases, although due in part to limited screening for these enzymes in clinical laboratories, the actual percentage is unknown. Carbapenemase-mediated carbapenem resistance in P. aeruginosa is a significant concern as it greatly limits the choice of anti-infective strategies, although detecting carbapenemase-producing P. aeruginosa in the clinical laboratory can be challenging. Such organisms also have been associated with nosocomial spread requiring infection prevention interventions. The carbapenemases …