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1883 citation(s) found for "Yu, Melissa".

Commentary on Hiding in Plain Sight: Protein Electrophoresis Profile Inconsistent with Patient’s Diagnosis
Snyder, Melissa R.

Clinical Chemistry | February 3, 2025 | Volume: 71 | Issue: 2 | Pages: 253-253

10.1093/clinchem/hvae162 | PMID 39899478 Get It

Risk Factors for Ectropion After Lower Eyelid and Cheek Reconstruction Following Mohs Micrographic Surgery
Rames, Jess D. , Rames, Melissa M. , Yu, Caroline , Figueroa, Nicole Sanchez, Akpala, C.O., Hussein, Sara , Demer, Addison M. , Figueroa, Nicole Gabriela Sanchez , Yu, Caroline Y, Sanchez Figueroa, Nicole, Akpala, Christeebela O, Sharaf, Basel A, Sanchez Figueroa, Nicole Gabriela , Akpala, Christeebela O., Sharaf, Basel , Wagner, Lilly H.

Plastic and Reconstructive Surgery - Global Open | February 3, 2025 | Volume: 13 | Issue: 2 | Pages: e6498

10.1097/gox.0000000000006498 | PMID 39906344 Get It

Background: Development of ectropion is a frequently reported complication after reconstruction of infraorbital Mohs defects. This study aimed to characterize preoperative and surgical factors contributing to ectropion development in patients undergoing reconstruction after Mohs micrographic surgery. Methods: We conducted a retrospective single-center case-control study on patients undergoing reconstruction of Mohs micrographic surgery defects involving the nonmarginal lower eyelid and upper cheek from 2011 to 2023. Pre- and postoperative photographs were reviewed to confirm defect location and postreconstructive eyelid malposition. Ectropion risk factors were determined with uni- and multivariate odds ratio analyses. Results: A total of 202 patients were included, 45 cases in the ectropion group and 157 in the control group. Negative orbital vector (P = 0.02), recurrent disease (P = 0.01), and greater defects size (P = 0.007) were associated with postreconstructive ectropion. Ectropion was more likely after multidisciplinary reconstruction (13.3% versus 1.4%, P < 0.001) and reconstruction with cervicofacial flaps (28.9% versus 4.2%, P < 0.0005); and less likely after primary closure (8.9% versus 28.5%, P < 0.001). Multivariate assessment (odds ratio [95% confidence interval], P value) revealed that combined cheek and eyelid defect involvement (4.32 [1.36–13.6], P = 0.01), larger size (1.07 [1.03–1.13], P < 0.001), and negative orbital vector (12.11 [2.65–65.42], P = 0.002) were independent risk factors for ectropion development. Conclusions: Combined cheek/lower eyelid defects and negative orbital vector increase the risk of postreconstructive ectropion. These findings can be used to optimize surgical technique and counsel patients on increased likelihood of this complication with possible need for revision surgery.
Abstract A012: Divergent impacts of DNMT3A and TET2 mutant clonal hematopoiesis on COVID-19 related outcomes
Lasho, Terra, Geyer, Susan M. , Finke, Christy M. , Mangaonkar, Abhishek A. , Simon, Vernadette, Rohakthar, Fariborz Rakhshan, Munankarmy, Amik, Harrington, Jonathan J. , Snyder, Melissa R. , Patnaik, Mrinal M. , Fernandez, Jenna , Ismail, Wazim Mohammed , Binder, Moritz , Mazzone, Amelia , Lee, Jeong‐Heon , Wang, Liguo , Munankarmy, Amik , Robertson, Keith D. , Gaspar‐Maia, Alexandre

Cancer Research | February 1, 2025 | Volume: 85 | Issue: 3_Supplement | Pages: A012-A012

10.1158/1538-7445.dnamethylation-a012 Get It

Abstract Background: DNMT3A and TET2 are epigenetic regulator genes commonly mutated in age-related clonal hematopoiesis (CH). Despite having opposed epigenetic functions, these mutations are associated with increased all-cause mortality and a low risk for hematological neoplasms. In this study, we make use of a natural inflammatory response occurring during COVID-19 to define the impact of these mutations on inflammation and outcomes. Methods: A cohort of 243 community-based patients (Olmsted County, MN) with COVID-19 were identified. CH status was determined on PBMC using error corrected sequencing (lower detection limit 0.5% VAF). In a subset of patients, we use multi-omics interrogation of the genome, transcriptome, and epigenome at single cell (sc) resolution along with DNA methylation, in PBMC, from patients with COVID-19 and CH. Results: We detected 97 CH mutations in 72 (29.6%) of 243 patients with COVID-19. The most frequent being DNMT3A (n=30, 30%) and TET2 (n=26, 28%). The presence of CH negatively impacted overall survival when restricted to TET2 and DNMT3A mutations. However, only DNMT3Amt CH retained age and comorbidity independent prognostication (HR 2.84, p = 0.022). We then assessed for changes in DNA methylation using Illumina MethylationEPIC array on patients with COVID-19 and DNMT3A (n=3) or TET2mt (n=4) CH. Site specific DNA methylation changes revealed significant loss of methylation in DNMT3Amt CH in comparison to TET2mt patients, with 10,944 hypomethylated and 1,160 hypermethylated sites. We found that actively transcribed states (Tx, TxWk) were more commonly hypomethylated in DNMT3Amt CH while enhancers (Enh) and promoters (TssA, TssAFlnk) were more commonly hypomethylated in TET2mt CH. We then conducted scDNA-seq in DNMT3Amt (n=3) and TET2mt (n=1) CH in COVID-19 and observed that while in TET2mt CH, mutations were largely restricted to classical and intermediate monocytes, in DNMT3Amt CH, mutations were seen in myeloid and lymphoid lineage cells. We performed scRNA-seq on patients with COVID-19 and DNMT3A (n=3) or TET2mt (n=6) CH. Differential gene expression analysis identified 1,569 upregulated genes in DNMT3Amt patients and 205 downregulated. Pathway analysis demonstrated an upregulation of genes involved in T cell survival, function, and inflammation in DNMT3Amt patients compared to TET2mt patients with a significant overexpression of GIMAP1, GIMAP4, IRF2, IL32 in multiple cell types. We correlated transcriptomic changes with chromatin accessibility using the 10X Genomics Multiome platform to profile both gene expression and open chromatin from the same samples. Analysis of global distribution of cut sites and differentially accessible peaks showed increased chromatin accessibility in DNMT3Amt CH, especially CD4+ T lymphocytes and NK cells. Conclusion: We demonstrate an age, sex, and comorbidity-independent adverse impact on mortality associated with DNMT3Amt CH in the context of COVID-19 and highlight transcriptomic and epigenetic differences between DNMT3A and TET2mt CH, with single cell resolution. Citation Format: Jenna A Fernandez, Wazim Mohammed Ismail, Moritz Binder, Terra Lasho, Susan M. Geyer, Amelia Mazzone, Christy M. Finke, Abhishek Mangaonkar, Jeong-Heon Lee, Liguo Wang, Vernadette A. Simon, Fariborz Rakhshan Rohakthar, Amik Munankarmy, Jonathan J. Harrington, Melissa R. Snyder, Keith D. Robertson, Alexandre Gaspar-Maia, Mrinal Patnaik. Divergent impacts of DNMT3A and TET2 mutant clonal hematopoiesis on COVID-19 related outcomes [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Methylation, Clonal Hematopoiesis, and Cancer; 2025 Feb 1-4; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2025;85(3 Suppl):Abstract nr A012.
195: UNEXPECTED TWIST: INTESTINAL ISCHEMIA IN AN LVAD RECIPIENT
Yadav, Bipin Kumar , Chaudhary, Ashlesha , Lyle, Melissa , Chaudhary, Sanjay, Yadav, Bipin, Guru, Pramod

Critical Care Medicine | January 31, 2025 | Volume: 53 | Issue: 1 | Pages: No page available

10.1097/01.ccm.0001099444.55205.f4 Get It

159: IMPACT OF A REHABILITATION PROGRAM IN PATIENTS WITH IMPELLA WAITING FOR A HEART TRANSPLANT
Jena, Anek , Pareek, Aayushi , Jonna, Sadhana , Olaizola, Gustavo , Raavi, Lekhya , Khanijo, Aditya , Siassi, Zara, Balasubramanian, Prasanth , Lyle, Melissa , Leoni, Juan , Sura, Lydia, Davis, Olivia , Birst, Jennifer, Wasowicz, Greg, Patel, Parag, Sanghavi, Devang , Huespe, Iván , Siassi, Zara, Isha, Shahin , Leoni, Juan Carlos , Franco, Pablo Moreno

Critical Care Medicine | January 31, 2025 | Volume: 53 | Issue: 1 | Pages: No page available

10.1097/01.ccm.0001099300.65000.19 Get It

Characterization of Factors Associated With Death in Deceased Patients With Mitochondrial Disorders
Ivaniuk, Alina , Anselm, Irina , Bowen, Aaron B. , Cohen, Bruce H. , Eminoğlu, Fatma Tuba , Estrella, Jane , Gallagher, Renata C. , Gannon, Jennifer , Gorman, Gráinne S. , Greene, Carol L. , Haas, Richard , Kapoor, Seema , Karaa, Amel , Koenig, Mary Kay , Kornblum, Cornelia , Lichter‐Konecki, Uta , Lopriore, Piervito , McFarland, Robert , Moe, Aye , Ng, Yi Shiau , Saneto, Russell P. , Scaglia, Fernando , Tarnopolsky, Mark A. , Walker, Melissa , Group, as the Hong Kong Mitochondrial Diseases Interest, Fung, Cheuk Wing , Wong, Tsz-sum, Belaramani, Kiran , Chan, Chun-kong , Chan, Wing-ki, Chan, Wai-lun Larry, Cheung, H. M. E., Cheung, Ka-yin, Chang, Richard Shek‐kwan , Cheung, Sing-ngai, Cheung, Tsz-Fung, Cheung, Yuk-fai, Chong, Shuk-ching Josephine, Chow, Chi-kwan Jasmine , Fan, Florence , Fok, Wai-ming Joshua , Fung, Tsui-hang Sharon , Hui, Kwok-fai, Hui, Ting-hin, Ko, Chun Hung, Kwan, Min-chung, Kwok, Anne Mei Kwun , Kwok, Sung-shing Jeffrey, Lai, Moon-sing, Lam, Yau-on, Lam, Ching‐Wan , Lau, Ming-chung, Law, Hiu-Fung, Lee, Wing‐Cheong , Leung, Kin-hang, Leung, Kit-yan, Li, Siu-hung, Ling, Tsz-ki, Liu, Kam Tim , Lui, Colin H. T., Luk, Ching-on, Luk, Ho‐Ming , Ma, Che-Kwan, Ma, Karen , Ma, Kam-hung , Mew, Yuen-ni, Mo, Alex, Hg, Sui-Fun, Poon, Grace Wing-kit , Sheng, Bun , Szeto, Cheuk-ling Charing, Tai, Shuk‐Mui, Tang, Jing-Liang, Tse, Choi-ting Alan , Tsung, Li-yan Lilian, Wong, Ho-ming June, Wong, Wing-yin Winnie, Wong, Kwok-kui, Wong, Suet-na Sheila , Wong, Chun-nei Virginia, Wong, Wai-shan Sammy, Wong, Chi-kin Felix, Wu, Shun-Ping, Wu, Hiu-fung Jerome , Yau, Man-Mut, Yau, Eric Kin Cheong , Yeung, Wai Lan , Yeung, Hon‐Ming Jonas , Yip, Kin-keung Edwin, Young, Pui-hong Terence, Yuan, Gao , Yuen, Yuet‐Ping , Yuen, Chi-lap, Anselm, Irina A , Bowen, Aaron , Ganetzky, Rebecca D , Gannon, Jennifer , Gorman, Grainne S , Greene, Carol , Gropman, Andrea L , Haas, Richard H , Hirano, Michio , Kapoor, Seema , Karaa, Amel , Koenig, Mary Kay , Kornblum, Cornelia , Kose, Engin , Larson, Austin A , Lichter-Konecki, Uta , Lopriore, Piervito , Mancuso, Michelangelo , McFarland, Robert , Moe, Aye Myat , Ng, Yi Shiau , Saneto, Russell P , Scaglia, Fernando , Sue, Carolyn M , Tarnopolsky, Mark , Walker, Melissa A , Parikh, Sumit , Cheuk-Wing, Fung , Wong, Tsz-Sum , Belaramani, Kiran , Chan, Chun-Kong , Chan, Wing-Ki , Chan, Wai-Lun Larry , Cheung, Hon-Wing , Cheung, Ka-Yin , Chang, Shek-Kwan , Cheung, Sing-Ngai , Cheung, Tsz-Fung , Cheung, Yuk-Fai , Chow, Chi-Kwan Jasmine , Chung, Hon-Yin B , Fan, Sin-Ying Florence , Fok, Wai-Ming Joshua , Fung, Tsui-Hang Sharon , Hui, Kwok-Fai , Hui, Ting-Hin , Hui, Joannie , Ko, Chun Hung , Kwan, Min-Chung , Kwok, Mei-Kwan Anne , Kwok, Sung-Shing Jeffrey , Lai, Moon-Sing , Lam, Yau-On , Lam, Ching-Wan , Lau, Ming-Chung , Law, Chun-Yiu Eric , Law, Hiu-Fung , Lee, Wing-Cheong , Leung, Kin-Hang , Leung, Kit-Yan , Li, Siu-Hung , Liu, Kam-Tim Timothy , Lo, Fai-Man , Lui, Colin , Luk, Ho-Ming , Ma, Che-Kwan , Ma, Karen , Ma, Kam-Hung , Mo, Alex , Hg, Sui-Fun , Poon, Wing-Kit Grace , Sheng, Bun , Tse, Choi-Ting Alan , Wong, Ho-Ming June , Wong, Wing-Yin Winnie , Wong, Kwok-Kui , Wong, Suet-Na Sheila , Wong, Chun-Nei Virginia , Wong, Wai-Shan Sammy , Wu, Hiu-Fung Jerome , Yau, Kin-Cheong Eric , Yeung, Wai-Lan , Yeung, Hon-Ming Jonas , Yip, Kin-Keung Edwin , Young, Pui-Hong Terence , Yuan, Gao , Yuen, Yuet-Ping Liz , Ivaniuk, Alina , Cohen, Bruce H , Ganetzky, Rebecca , Larson, Austin , Morava, Éva , Sue, Carolyn M. , Parikh, Sumit , Group, as the Hong Kong Mitochondrial Diseases Interest, Fong, Ka-Wing, Lee, Han‐Chih Hencher , Tang, Jing-Liang, Wu, Hui-Jun

Neurology | January 30, 2025 | Volume: 104 | Issue: 4 | Pages: No page available

10.1212/wnl.0000000000209779 | PMID 39883904 Get It

Abstract TP246: Transcranial Doppler (TCD) Parameters in Predicting Outcomes Following Successful Mechanical Thrombectomy of Large Vessel Occlusions in Anterior Circulation: A Systematic Review and Meta-Analysis
Ravi, Vikas , Pirahanchi, Yasaman , Penagos, Julian Carrion, Bowers, Jeffrey, Hailey, Lovella, Mortin, Melissa, Modir, Royya , Agrawal, Kunal , Hemmen, Thomas , Meyer, Brett C. , Meyer, Dawn , Jazayeri, Seyed Behnam , Sabayan, Behnam , Bowers, Jeffrey, Agrawal, Kunal, Shahripour, Reza Bavarsad

Stroke | January 30, 2025 | Volume: 56 | Issue: Suppl_1 | Pages: No page available

10.1161/str.56.suppl_1.tp246 Get It

Introduction: Mechanical thrombectomy (MT) is a primary treatment for acute ischemic stroke due to large vessel occlusions. While effective, 20-40% of patients experience hemorrhagic transformation (HT), and around 50% fail to achieve favorable functional outcomes. Transcranial Doppler (TCD) is a non-invasive and cost-effective method for real-time monitoring of hemodynamic status following MT. However, the prognostic value of TCD parameters in predicting HT and poor functional outcome is unclear. We performed a systematic review and meta-analysis of 4 TCD parameters (mean flow velocity (MFV), MFV index, peak systolic velocity (PSV), and pulsatility index (PI) in patients with and without HT and favorable vs poor functional recovery (modified Rankin Scale (mRS) 0-2 vs 3-6). Methods: PubMed, Embase, and Scopus were searched on July 25, 2024 to identify observational studies in which TCD parameters were measured within 48 hours from successful MT (Thrombolysis in Cerebral Infarction 2b–3) of anterior circulation. Risk of bias assessment was performed using a standardized tool tailored for TCD studies. The standardized mean difference (Hedges’ g) with 95% CI and risk ratios (RRs) with 95% CI were calculated using random-effects models. The review was prospectively registered on PROSPERO (registration number CRD42024575381). Results: Eleven studies met inclusion criteria. No study had high risk of bias. MFV and MFV index were higher in patients with HT+ compared with HT- (Hedges' g = 0.42 and 0.54, p = 0.015 and 0.005, respectively). Patients with MFV index ≥1.3 showed a higher risk of all HT (RR = 2.01, 95% CI = 1.27–3.17, p = 0.003), symptomatic HT (RR, 4.68; 95% CI,1.49–14.65, p=0.008), and poor functional recovery at 90 days (RR, 1.66; 95% CI,1.32–2.08, p<0.001), respectively. There was no difference in mean PSV (p=0.1) and PI (p=0.3) among groups with and without HT. Conclusion: Our study highlights the prognostic value of TCD parameters, particularly MFV index, in predicting HT, symptomatic HT, and poor functional recovery after successful MT in the anterior circulation. Our findings were limited by low number of studies. Large-scale and multi-center studies are needed to confirm these findings and validate the MFV index as a reliable predictor to improve post-thrombectomy care.
Abstract WP283: Comparative Accuracy of Transcranial Doppler, Transthoracic Echocardiography, Transesophageal Echocardiography, and Cardiac CT in Detecting Right-to-Left Shunt in Embolic Stroke of Undetermined Source
Ravi, Vikas , Pirahanchi, Yasaman , Penagos, Julian Carrion, Bowers, Jeffrey, Meyer, Brett C. , Agrawal, Kunal , Modir, Royya , Hemmen, Thomas , Meyer, Dawn , Hailey, Lovella, Mortin, Melissa, Jazayeri, Seyed Behnam , Bowers, Jeffrey, Agrawal, Kunal, Shahripour, Reza Bavarsad

Stroke | January 30, 2025 | Volume: 56 | Issue: Suppl_1 | Pages: No page available

10.1161/str.56.suppl_1.wp283 Get It

Introduction: Embolic Stroke of Undetermined Source (ESUS) represents about 25% of ischemic strokes, with patent foramen ovale (PFO) involved in roughly 25% of those cases. Recent studies (REDUCE, CLOSE, RESPECT) indicate that PFO closure may benefit select patients. Accurate PFO diagnosis is crucial for treatment decisions but current methods, such as transcranial Doppler (TCD) with bubble study, transthoracic echocardiography with bubble study (TTE), transesophageal echocardiography (TEE), and cardiac computed tomography (CT), vary in accuracy. This study aims to assess the diagnostic performance of TCD compared to TTE, TEE, and cardiac CT, to determine the most reliable modality for detecting PFO in patients with ESUS. Methods: We conducted a retrospective analysis of ESUS patients aged 18 and older referred to our vascular lab between July 2023 and September 2024. Each patient underwent at least two PFO detection methods: TCD with bubble study, TTE with bubble study, TEE, and cardiac CT. PFO presence was confirmed if identified by at least two detection methods. Patients with extracardiac shunts were excluded. Sensitivity, specificity, and overall test performance were evaluated using the Area Under the Curve (AUC) of a Receiver Operating Characteristic (ROC) curve, with higher AUC values indicating better performance. Differences in AUCs were assessed using DeLong’s test. Statistical analysis was performed using Analyse-it for Microsoft Excel (version 2.30). Results: Of 187 enrolled patients, 63 (33.7%) had evidence of right-to-left shunt. The mean age of the cohort was 63 ± 18 years, with 51% being male. PFO was confirmed in 36 patients. Sensitivity was highest for TCD (93.1%), followed by TTE (87.1%), TEE (86.7%), and cardiac CT (42.9%). Specificity was highest for cardiac CT (87.5%), followed by TTE (84%), TCD (59.1%), and TEE (47.1%). The AUC was highest for TTE (AUC: 0.85, 95% CI: 0.76–0.95), followed by TCD (AUC: 0.75, 95% CI: 0.64–0.87), TEE (AUC: 0.66, 95% CI: 0.50–0.81), and cardiac CT (AUC: 0.65, 95% CI: 0.42–0.88). No statistically significant differences in diagnostic performance across pairwise comparisons were found (p > 0.05). Conclusion: TCD with bubble study is highly sensitive for screening right-to-left shunt, while cardiac CT is highly specific for detecting PFO in ESUS patients. Further studies with larger sample sizes are needed to confirm these findings and refine diagnostic strategies.
P-1498. Contezolid is Active against Methicillin-Resistant Staphylococcus aureus in Experimental Rat Foreign Body Osteomyelitis
Karau, Melissa J. , Koscianski, Christina, Greenwood‐Quaintance, Kerryl E. , Mandrekar, Jay , Herren, Sebastian , Patel, Robin

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.1667 Get It

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of orthopedic implant-associated infection, where S. aureus can survive intracellularly and form biofilms. Vancomycin has poor activity against staphyloccoccal biofilms. Although rifampin is effective against staphylococcoal biofilms and has intracellular activity, resistance may develop when it is used as a single agent. Contezolid is a novel oxazolidinone with reported activity against S. aureus in vitro and in vivo in both murine systemic and thigh infection models. Here, we assessed the in vivo activity of contezolid, with and without rifampin, in a rat model of foreign body osteomyelitis. Figure 1. Quantities of MRSA IDRL-6169 recovered from A. tibia B. K-wire. Circles represent values from individual animals; horizontal lines represent mean values. Compared to no treatment: *p=0.0186 **p&lt;0.0002 Methods The left tibia of 60 male Wister rats were inoculated with arachidonic acid (sclerosing agent) and 106 cfu MRSA IDRL-6169 and a K-wire implanted. After four weeks, rats received either no treatment, contezolid (50 mg/kg orally, every 12 h), rifampin (10 mg/kg intraperitoneally every 12 h), rifampin plus contezolid, or vancomycin (75 mg/kg intraperitoneally, every 12 h) plus rifampin for 21 days. Following treatment, tibiae were harvested and cyropulverized. Tibiae and K-wires were cultured separately, and results reported as log10 cfu/gram of bone or K-wire (limit of detect 0.1 log10), respectively. Wilcoxon rank-sum test and false discovery rates were performed and p&lt; 0.05 considered significant. Results Results are shown in Figure 1. MRSA was recovered from tibiae and K-wires of all untreated animals, at means of 5.1 log10 cfu/bone and 3.0 log10 cfu/K-wire, respectively. There was a 1.0 log10 cfu/g mean reduction in MRSA recovered from the tibiae of contezolid-treated rats compared to untreated rats (p=0.0186), and a 0.2 log10 reduction on K-wires. No MRSA was recovered from the tibiae or K-wires in animals receiving rifampin, whether alone or in combination with contezolid or vancomycin. Conclusion Contezolid was active against MRSA in a rat model of foreign body osteomyelitis, reducing bacterial loads in bone, albeit not on K-wires, unless co-administered with rifampin. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria
P-2225. Interactions between phage and host bacteria in immunized rabbit serum
Karau, Melissa J. , Koscianski, Christina, Christensen, Trace , Herren, Sebastian , Patel, Robin

Open Forum Infectious Diseases | January 29, 2025 | Volume: 12 | Issue: Supplement_1 | Pages: No page available

10.1093/ofid/ofae631.2379 Get It

Abstract Background Phage therapy is being evaluated to treat bacterial infections. Host-related factors that might abrogate phage efficacy remain incompletely characterized. Phage aggregation has been hypothesized to protect phages in harsh environments. Herein, effects of immunized rabbit sera on phage aggregation were assessed. Methods Three New Zealand rabbits were immunized weekly for 3 weeks by intramuscular injection of phage K. Serum samples were collected weekly at times 0, 7, 14, 21 and 28. Development of an antibody response was confirmed by ELISA. Phage K was exposed to immunized serum with or without heat-inactivated host bacterium (Staphylococcus aureus ATCC 19685) as follows. 45 µl of phage K (1010±1 plaque forming units/mL [pfu/ml]) was mixed with 5 µl immunized serum diluted 1:1000 with or without heat-inactivated bacterial host in phosphate buffered saline (PBS). After incubation, exposed phage was visualized using transmission electron microscopy (TEM, JEOL) at 80kV. Results Phage K immunization elicited a strong IgG response. Exposure to immunized serum led to a decrease in viable phage over time, abrogated by adding heat-inactivated bacteria (Fig 1). TEM imaging showed phage clustering with exposure to immunized serum (Fig 2A); clusters appeared disorganized with concomitant exposure to heat-inactivated host bacteria (Fig 2B). Exposure of phage to heat-inactivated bacteria without serum yielded evenly distributed phage, with minimal clustering (Fig 2C). Conclusion Phage K exposure elicited a neutralizing immune response associated with decreased phage survival in immunized serum, prolonged by adding heat-inactivated host bacteria. TEM imaging showed phage K clustering in different ways depending on the microenvironment encountered. Biological relevance and mechanistic underpinnings of these phenomena need further characterization. Disclosures Robin Patel, MD, a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, a: See above|MicuRx Pharmaceuticals and BIOFIRE: Grant/Research Support|PhAST, Day Zero Diagnostics, Abbott Laboratories, Sysmex, DEEPULL DIAGNOSTICS, S.L., Netflix, Oxford Nanopore Technologies and CARB-X: Advisor/Consultant|Up-to-Date and the Infectious Diseases Board Review Course.: Honoraria