Publications by authors named "Juliana Sobczyk"

3 Publications

  • Page 1 of 1

Efficient and effective single-step screening of individual samples for SARS-CoV-2 RNA using multi-dimensional pooling and Bayesian inference.

J R Soc Interface 2021 06 16;18(179):20210155. Epub 2021 Jun 16.

Department of Chemistry, University of Utah, Salt Lake City, UT, USA.

Rapid and widespread implementation of infectious disease surveillance is a critical component in the response to novel health threats. Molecular assays are the preferred method to detect a broad range of viral pathogens with high sensitivity and specificity. The implementation of molecular assay testing in a rapidly evolving public health emergency, such as the ongoing COVID-19 pandemic, can be hindered by resource availability or technical constraints. We present a screening strategy that is easily scaled up to support a sustained large volume of testing over long periods of time. This non-adaptive pooled-sample screening protocol employs Bayesian inference to yield a reportable outcome for each individual sample in a single testing step (no confirmation of positive results required). The proposed method is validated using clinical specimens tested using a real-time reverse transcription polymerase chain reaction test for SARS-CoV-2. This screening protocol has substantial advantages for its implementation, including higher sample throughput, faster time to results, no need to retrieve previously screened samples from storage to undergo retesting, and excellent performance of the algorithm's sensitivity and specificity compared with the individual test's metrics.
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http://dx.doi.org/10.1098/rsif.2021.0155DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8205536PMC
June 2021

Comparison of Multiplex Gastrointestinal Pathogen Panel and Conventional Stool Testing for Evaluation of Patients With HIV Infection.

Open Forum Infect Dis 2020 Jan 6;7(1):ofz547. Epub 2020 Jan 6.

Department of Pathology, University of California, San Diego, La Jolla, California, USA.

Background: Gastrointestinal pathogen panels (GPPs) are increasingly used to identify stool pathogens, but their impact in people with HIV (PWH) is unknown. We performed a retrospective cohort study comparing GPP and conventional stool evaluation in PWH.

Methods: We included all PWH who underwent GPP (Biofire Diagnostics; implemented September 15, 2015) or conventional testing, including stool culture, polymerase chain reaction testing, fluorescent smears for or and ova and parasite exams (O&P) from 2013 to 2017. A total of 1941 specimens were tested, with 169 positive specimens detected in 144 patients. We compared result turnaround time, pathogen co-infection, antibiotic treatment, and treatment outcomes between positive specimens detected by conventional testing vs GPP.

Results: Overall, 124 patient samples tested positive by GPP, compared with 45 patient specimens by conventional testing. The GPP group demonstrated a higher co-infection rate (48.4% vs 13.3%;  < .001) and quicker turnaround time (23.4 vs 71.4 hours;  < .001). The GPP identified 29 potential viral infections that were undetectable by conventional stool tests. Unnecessary anti-infective therapy was avoided in 9 of 11 exclusively viral infections. Exclusively nonpathogenic parasites (n = 13) were detected by conventional stool tests, the majority of which were treated with metronidazole. There were no significant differences in clinical outcomes between groups.

Conclusions: In PWH, GPP implementation improved antibiotic stewardship through shorter turnaround times and detection of enteric viral pathogens.
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http://dx.doi.org/10.1093/ofid/ofz547DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6970129PMC
January 2020

Factors influencing transfusion-associated HLA sensitization in patients bridged to heart transplantation using ventricular assist device.

Clin Transplant 2020 01 31;34(1):e13772. Epub 2019 Dec 31.

Department of Pathology, University of California, San Diego, La Jolla, CA, USA.

Background: Bridging heart failure patients with mechanical ventricular assist devices (VAD) enables access to transplantation. However, VAD is associated with increased risk for anti-HLA antibodies associated with rejection of subsequent allografts. Factors determining alloantibody formation in these patients remain undefined.

Methods: We performed a single-center retrospective cohort study of 164 patients undergoing heart transplantation from 2014 to 2017. Medical records including use of VAD, transfused blood products, anti-HLA antibody testing, crossmatch, and time to transplant were evaluated.

Results: Patients received an average of 13.8 red blood cell and 1.9 single-donor platelet units associated with VAD. There was a 28.7% increase in the incidence of anti-HLA antibodies after VAD. Development of anti-HLA antibodies did not correlate with volume or type of blood products, but with pre-VAD HLA sensitization status; relative risk of new alloantibodies in patients with pre-VAD antibodies was 3.5-fold higher than those without prior antibodies (P = .008). Development of new anti-HLA antibodies was associated with an increased time to transplant (169 vs 330 days, P = .013).

Conclusions: Our findings indicate that the presence of anti-HLA antibodies pre-VAD was the most significant risk factor for developing additional antibodies post-VAD, suggesting that a subset of patients may be predisposed to alloantibody formation.
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http://dx.doi.org/10.1111/ctr.13772DOI Listing
January 2020
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