Browsing by Author "Rao, Jayasimha"

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    An evaluation of a new rapid qPCR test for the detection of 2019-novel coronavirus nucleocapsid (N1) gene in wastewater in Roanoke and Salem VA sewersheds
    Lehrer, Lia W.; Lewis, Anna; Tolliver, Susan A.; Degen, Marcia; Singh, Rekha; Houser, Sara R.; Rao, Jayasimha (IWA Publishing, 2024-08)
    The COVID-19 pandemic initiated public interest in wastewater-based epidemiology (WBE). Public and private entities responded to the need to produce timely and accurate data. LuminUltra and Hach partnered to provide a rapid, field-based quantitative polymerase chain reaction (qPCR) test for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater. This study evaluates the Hach GeneCount SARS-CoV-2 Wastewater RT-qPCR Assay Kit and LuminUltra GeneCount® Q-16 RT-PCR instrument. The Hach LuminUltra methods were compared to the Promega Wizard® Enviro Total Nucleic Acid kit and Bio-Rad CFX Opus 96 Real-time PCR Detection System. Over a 12-week period, wastewater samples were collected weekly from seven locations in the Roanoke/Salem, VA sewersheds. Concentration and extraction of the viral RNA were followed by qPCR analysis. The target gene for detection was the nucleocapsid gene (N1) of the SARS-CoV-2 virus. Costs, ease of use, time to produce results, sample preparation, and data comparisons were considered. The comparison determined that the Hach LuminUltra method and instrument were more affordable, consumed less time, and required less technical expertise. While the new method was specific, it had low sensitivity. This evaluation suggests the Hach LuminUltra method should be reserved for limited situations requiring onsite field analysis where data accuracy is not essential.
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    Catheter-based Medical Device Biofilm Ablation Using Histotripsy: A Parameter Study
    Morse, Ryan; Childers, Christopher; Nowak, Elizabeth; Rao, Jayasimha; Vlaisavljevich, Eli (Elsevier, 2023-07-01)
    OBJECTIVE: Biofilm formation in medical catheters is a major source of hospital-acquired infections which can produce increased morbidity and mortality for patients. Histotripsy is a non-invasive, non-thermal focused ultrasound therapy and recently has been found to be effective at removal of biofilm from medical catheters. Previously established histotripsy methods for biofilm removal, however, would require several hours of use to effectively treat a full-length medical catheter. Here, we investigate the potential to increase the speed and efficiency with which biofilms can be ablated from catheters using histotripsy. METHODS: Pseudomonas aeruginosa (PA14) biofilms were cultured in in vitro Tygon catheter mimics and treated with histotripsy using a 1 MHz histotripsy transducer and a variety of histotripsy pulsing rates and scanning methods. The improved parameters identified in these studies were then used to explore the bactericidal effect of histotripsy on planktonic PA14 suspended in a catheter mimic. RESULTS: Histotripsy can be used to remove biofilm and kill bacteria at substantially increased speeds compared with previously established methods. Near-complete biofilm removal was achieved at treatment speeds up to 1 cm/s, while a 4.241 log reduction in planktonic bacteria was achieved with 2.4 cm/min treatment. CONCLUSION: These results represent a 500-fold increase in biofilm removal speeds and a 6.2-fold increase in bacterial killing speeds compared with previously published methods. These findings indicate that histotripsy shows promise for the treatment of catheter-associated biofilms and planktonic bacteria in a clinically relevant time frame.
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    Complete Genome Sequence of Providencia stuartii CMC-4104, Isolated from a Human Splenic Abscess, Containing Multiple Copies of NDM-1 and PER-1 Carbapenem Resistance Genes
    Rao, Jayasimha; Stornelli, Nicholas K.; Everson, Nathan A.; McDaniel, Lauren F.; Gomez De La Espriella, Mariana; Faulhaber, Jason R.; Todd, S. Michelle; Lahmers, Kevin K.; Jensen, Roderick V. (American Society for Microbiology, 2022-08-04)
    We report the complete genome sequence of a clinical isolate of Providencia stuartii strain CMC-4104, isolated from a splenic abscess. Oxford Nanopore Technologies (ONT) and Illumina sequencing reads were assembled using Geneious to generate a 4,504,925-bp circular chromosome containing multiple copies of the NDM-1 and PER-1 genes in a genomic resistance island.
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    Complete Genome Sequence of Pseudomonas aeruginosa CMC-097, Isolated from a Ventilator-Associated Pneumonia Patient, Containing a Novel Carbapenem Resistance Class 1 Integron
    Rao, Jayasimha; Adenikinju, Adenike; Kerkering, Thomas M.; Garner, Dorothy C.; Jensen, Roderick, V (2021-09)
    We report the complete genome of a clinical strain of Pseudomonas aeruginosa CMC-097, which was isolated from a ventilator-associated pneumonia patient with a chronic infection. Illumina sequence reads were assembled using Geneious to yield a 7,044,064-bp circular chromosome containing a carbapenem resistance integron, In2020.
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    Complete Genome Sequence of Pseudomonas aeruginosa CMC-115, a Clinical Strain from an Acute Ventilator-Associated Pneumonia Patient
    Adenikinju, Adenike; Jensen, Roderick V.; Kerkering, Thomas M.; Garner, Dorothy C.; Rao, Jayasimha (2020-07)
    We report the complete genome of clinical strain Pseudomonas aeruginosa CMC-115, which was isolated from an acute ventilator-associated pneumonia patient. Illumina sequencing reads were assembled using Geneious to yield a 6,375,262-bp circular chromosome that exhibited an unusual ferrichrome receptor in the pyoverdine synthesis locus and the absence of type 3 secretion system genes.
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    Focused Ultrasound Biofilm Ablation: Investigation of Histotripsy for the Treatment of Catheter-Associated Urinary Tract Infections (CAUTIs)
    Childers, Christopher; Edsall, Connor; Gannon, Jessica; Whittington, Abby R.; Muelenaer, Andre A.; Rao, Jayasimha; Vlaisavljevich, Eli (IEEE, 2021-09-01)
    Urinary catheters often become contaminated with biofilms, resulting in catheter-associated urinary tract infections (CAUTIs) that adversely affect patient outcomes. Histotripsy is a non-invasive focused ultrasound therapy previously developed for the non-invasive ablation of cancerous tumors and soft tissues. Histotripsy has also previously shown the ability to treat biofilms on glass slides and surgical meshes. Here, we investigate the potential of histotripsy for the treatment of CAUTIs for the first time in vitro. Clinically relevant catheter materials (Tygon, Silicone, and latex catheter mimics) and commonly used clinical catheters were tested to determine the feasibility of producing luminal histotripsy bubble clouds. A Pseudomonas aeruginosa (strain PA14) biofilm model was developed and tested to produce luminal biofilms in an in vitro Tygon catheter mimic. This model was treated with histotripsy to determine the ability to remove a luminal biofilm. Finally, the bactericidal effects of histotripsy were tested by treating PA14 suspended inside the Tygon catheter mimic. Results showed that histotripsy produced precise luminal cavitation within all tested catheter mimics and clinical catheters. Histotripsy treatment of a PA14 biofilm with histotripsy reduced luminal biofilm OD590 signal down to background levels. Further, the treatment of suspended PA14 in LB showed a 3.45±0.11 log10 reduction in CFU/mL after 6 histotripsy scans across the catheter mimics. Overall, the results of this study demonstrate the potential of histotripsy to provide a new modality for removing bacterial biofilms from catheter-based medical devices and suggest that additional work is warranted to investigate histotripsy for the treatment of CAUTIs and other biomaterial-associated infections.
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    Particle-mediated Histotripsy for the Targeted Treatment of Intraluminal Biofilms in Catheter-based Medical Devices
    Childers, Christopher; Edsall, Connor; Mehochko, Isabelle; Mustafa, Waleed; Yuksel Durmaz, Yasemin; Klibanov, Alexander L.; Rao, Jayasimha; Vlaisavljevich, Eli (American Association for the Advancement of Science (AAAS), 2022-08-09)
    Objective: This paper is an initial work towards developing particle-mediated histotripsy (PMH) as a novel method of treating catheter-based medical device (CBMD) intraluminal biofilms. Impact Statement: CBMDs commonly become infected with bacterial biofilms leading to medical device failure, infection, and adverse patient outcomes. Introduction: Histotripsy is a noninvasive focused ultrasound ablation method that was recently proposed as a novel method to remove intraluminal biofilms. Here, we explore the potential of combining histotripsy with acoustically active particles to develop a PMH approach that can noninvasively remove biofilms without the need for high acoustic pressures or real-time image guidance for targeting. Methods: Histotripsy cavitation thresholds in catheters containing either gas-filled microbubbles (MBs) or fluid-filled nanocones (NCs) were determined. The ability of these particles to sustain cavitation over multiple ultrasound pulses was tested after a series of histotripsy exposures. Next, the ability of PMH to generate selective intraluminal cavitation without generating extraluminal cavitation was tested. Finally, the biofilm ablation and bactericidal capabilities of PMH were tested using both MBs and NCs. Results: PMH significantly reduced the histotripsy cavitation threshold, allowing for selective luminal cavitation for both MBs and NCs. Results further showed PMH successfully removed intraluminal biofilms in Tygon catheters. Finally, results from bactericidal experiments showed minimal reduction in bacteria viability. Conclusion: The results of this study demonstrate the potential for PMH to provide a new modality for removing bacterial biofilms from CBMDs and suggest that additional work is warranted to develop histotripsy and PMH for treatment of CBMD intraluminal biofilms.
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    The absence of nosemosis in eastern bumblebees (Bombus impatiens Cresson) from regions of Roanoke and New River Valley
    Samarasinghe, Binuk; Ausburne, Thomas; Blankenship, Christopher; Lin, Kaung; Linsenman, Kathleen; Rao, Jayasimha; Bhatta, Chet (2023-12-01)
    In a study of 220 eastern bumblebee specimens collected from the Roanoke and New River Valley areas, PCR analysis of the gut lumen revealed the absence of Nosema spp. infections, challenging prevailing assumptions about their prevalence in bumblebee populations. The outcome underscores the need for further research to determine the factors contributing to this absence, including the unique ecological context of the study area. These findings highlight the significance of host susceptibility and survivability, emphasizing the complexity associated with parasite-host interactions within bumblebees.