Nucleic Amplification Tests Research Articles

Multi-omics analysis reveals COVID-19 vaccine induced attenuation of inflammatory responses during breakthrough disease

The immune mechanisms mediating COVID-19 vaccine attenuation of COVID-19 remain undescribed. We conducted comprehensive analyses detailing immune responses to SARS-CoV-2 virus in blood post-vaccination with ChAdOx1 nCoV-19 or a placebo. Samples from randomised placebo-controlled trials (NCT04324606 and NCT04400838) were taken at baseline, onset of COVID-19-like symptoms, and 7 days later, confirming COVID-19 using nucleic amplification test (NAAT test) via real-time PCR (RT-PCR). Serum cytokines were measured with multiplexed immunoassays. The transcriptome was analysed with long, short and small RNA sequencing. We found attenuation of RNA inflammatory signatures in ChAdOx1 nCoV-19 compared with placebo vaccinees and reduced levels of serum proteins associated with COVID-19 severity. KREMEN1, a putative alternative SARS-CoV-2 receptor, was downregulated in placebo compared with ChAdOx1 nCoV-19 vaccinees. Vaccination ameliorates reductions in cell counts across leukocyte populations and platelets noted at COVID-19 onset, without inducing potentially deleterious Th2-skewed immune responses. Multi-omics integration links a global reduction in miRNA expression at COVID-19 onset to increased pro-inflammatory responses at the mRNA level. This study reveals insights into the role of COVID-19 vaccines in mitigating disease severity by abrogating pro-inflammatory responses associated with severe COVID-19, affirming vaccine-mediated benefit in breakthrough infection, and highlighting the importance of clinically relevant endpoints in vaccine evaluation.

The impact of non-disclosure of HIV status and antiretroviral therapy on HIV recency testing and incidence algorithms.

Accurate HIV incidence estimates among blood donors are necessary to assess the effectiveness of programs aimed at limiting transfusion-transmitted HIV. We assessed the impact of undisclosed HIV status and antiretroviral (ARV) use on HIV recency and incidence estimates using increasingly comprehensive recent infection testing algorithms. Using 2017 donation data from first-time and lapsed donors, we populated four HIV recency algorithms: (1) serology and limiting-antigen avidity testing, (2) with individual donation nucleic amplification testing (ID-NAT) added to Algorithm 1, (3) with viral load added to Algorithm 2 and (4) with ARV testing added to Algorithm 3. Algorithm-specific mean durations of recent infection (MDRI) and false recency rates (FRR) were calculated and used to derive and compare incidence estimates. Compared with Algorithm 4, progressive algorithms misclassified fewer donors as recent: Algorithm 1: 61 (12.1%); Algorithm 2: 14 (2.8%) and Algorithm 3: 3 (0.6%). Algorithm-specific MDRI and FRR values resulted in marginally lower incidence estimates: Algorithm 1: 0.19% per annum (p.a.) (95% confidence interval [CI]: 0.13%-0.26%); Algorithm 2: 0.18% p.a. (95% CI: 0.13%-0.22%); Algorithm 3: 0.17% p.a. (95% CI: 0.13%-0.22%) and Algorithm 4: 0.17% p.a. (95% CI: 0.13%-0.21%). We confirmed significant misclassification of recent HIV cases when not including viral load and ARV testing. Context-specific MDRI and FRR resulted in progressively lower incidence estimates but did not fully account for the context-specific variability in incidence modelling. The inclusion of ARV testing, in addition to viral load and ID-NAT testing, did not have a significant impact on incidence estimates.

Clinico-epidemiological profile of 75 cases of TB meningitis in children and adoloscents

BackgroundNeurological involvement is one of the deadliest forms of tuberculosis especially in pediatric population. AimTo study the clinico-epidemiological profile of 75 cases of pediatric TB meningitis and its co-relation with CBNAAT/TRUENAT positivity. Study designProspective study in children and adolescents less than 18 years in Tertiary Health care centre in New Delhi. Subjects and methods75 Children and adolescents less than 18 years with Probable TBM as per NTEP guidelines were enrolled. Clinical, Radiological and CSF analysis were carried out in all the patients. Results75 children were enrolled out of which 61% were females. The most common symptom at presentation was fever followed by loss of appetite and weight loss. Neck rigidity was present in 66% cases followed by posturing in 25% cases. 46% patients presented in Stage 2. Tuberculin skin test was positive in 16% cases and 20% patients had evidence of pulmonary TB on chest Xray. Hydrocephalous was the most common finding in neuroimaging present in 61% cases. In majority of the cases, CSF analysis revealed pleocytosis with lymphocyte predominance, low glucose and high protein values. Nucleic amplification tests (CBNAAT/TRUENAT) were positive in 33% cases and 4 out of 75 were detected to have rifampicin resistance. There was no co-relation identified between Stage at presentation, tuberculin positivity and CSF analysis with CBNAAT/TRUENAT positivity. Six patients expired within 2 weeks of presentation. ConclusionThe diagnosis of TBM is a composite of clinical, radiological and CSF analysis parameters. Being a paucibacillary sample, the yield of TB bacilli in NAAT studies remains moderately low. Moreover, detection of TB bacilli in CBNAAT/TRUENAT is independent of the CSF cytological and biochemical profile, and is also independent of the Stage of TBM.

Truenat: Can it be A Game Changer in Extrapulmonary Tuberculosis?

Tuberculosis is a leading health problem worldwide, with India accounting for the majority of cases. Owing to the diverse clinical presentation and paucibacillary nature of extrapulmonary tuberculosis, it is tough to diagnosis by routine microbiological methods. Newer chip/cartridge based nucleic amplification tests (NAATs) like Truenat and Xpert have proved to be game changer in diagnosis of pulmonary tuberculosis. However, role of Truenat in extrapulmonary tuberculosis is still to be evaluated. This study was undertaken to evaluate the diagnostic yield of truant in various extrapulmonary tuberculosis. The study was conducted during 01 June 2021 to 31 July 2022. Of the total 1481 samples received during study, 761 (52%) were extrapulmonary samples. The highest yield of 36% was found in pus aspirate, followed by a 12% yield in pleural fluid. Overall yield of 12% in various extrapulmonary samples is encouraging. Further studies are required for evaluating Truenat role in rapid diagnosis of EPTB and rifampicin resistance detection for better patient care.

673. Sniffing Out Adherence: Evaluation of a Clostridioides difficile guideline at a Tertiary Academic Medical Center

Abstract Background Tufts Medical Center’s (TMC) Antimicrobial Stewardship Team (AMT) in collaboration with gastroenterology (GI) developed an institutional treatment algorithm to guide appropriate inpatient management of Clostridioides difficile infection (CDI). The CD treatment algorithm was revised in April 2022 to reflect updated national clinical practice guidelines and disseminated to TMC providers. Our study aimed to assess provider compliance to TMC’s CD treatment algorithm. Methods A retrospective study of adult patients hospitalized from April 15, 2022 to October 31, 2022 and tested for CD was conducted. We collected patient demographics, white blood cell count, serum creatinine (SC), length of stay, CD treatment, Infectious Diseases (ID) & GI consult, occurence of severe CDI (defined as white blood cell > 15 K/uL or SC > 1.5 mg/dL), occurrence of recurrent CDI, and immunocompromised status (defined by having had organ or bone marrow transplant, receiving immunomodulatory therapy or chronic steroids). A 2-step Clostridioides difficile (CD) testing algorithm was used. For CD toxin A/B & glutamate dehydrogenase antigen (GDH) indeterminate results, reflex to nucleic amplification test (NAAT) was performed only with AMT approval. Results A total of 111 inpatients had CD toxin/GDH stool testing; 70 (63%) positive and 41 (37%) indeterminate. Of patients who had an indeterminate CD toxin/GDH, none had subsequent CD NAAT testing, and none receive CDI treatment. Of the others, 81 (73%), 23 (21%), and 7 (6%) were diagnosed with non-severe, severe, and fulminant CDI, respectively. The overall adherence to the institutional CD treatment algorithm was 58% (figure 1). More patients were appropriately treated with oral vancomycin (11, 65%) compared to those who were appropriately treated with fidaxomicin (9, 24%). Guidance adherence was (3) 38% among patients who had one or more recurrent episodes of CD, and none received suggested ID or GI consultation for additional CDI treatment consideration. Conclusion Adherence to institutional CD treatment algorithm was low. This study highlights opportunities to improve prescription of first line CDI therapy, especially among patients who are at higher risk for recurrence. Disclosures Maureen Campion, PharmD, BCIDP, Shinoigi: Speaker

The temporal dynamics of Plasmodium species infection after artemisinin-based combination therapy (ACT) among asymptomatic children in the Hohoe municipality, Ghana

BackgroundThe routine surveillance of asymptomatic malaria using nucleic acid-based amplification tests is essential in obtaining reliable data that would inform malaria policy formulation and the implementation of appropriate control measures.MethodsIn this study, the prevalence rate and the dynamics of Plasmodium species among asymptomatic children (n = 1697) under 5 years from 30 communities within the Hohoe municipality in Ghana were determined.Results and discussionThe observed prevalence of Plasmodium parasite infection by polymerase chain reaction (PCR) was 33.6% (571/1697), which was significantly higher compared to that obtained by microscopy [26.6% (451/1697)] (P < 0.0001). Based on species-specific analysis by nested PCR, Plasmodium falciparum infection [33.6% (570/1697)] was dominant, with Plasmodium malariae, Plasmodium ovale and Plasmodium vivax infections accounting for 0.1% (1/1697), 0.0% (0/1697), and 0.0% (0/1697), respectively. The prevalence of P. falciparum infection among the 30 communities ranged from 0.0 to 82.5%. Following artesunate-amodiaquine (AS + AQ, 25 mg/kg) treatment of a sub-population of the participants (n = 184), there was a substantial reduction in Plasmodium parasite prevalence by 100% and 79.2% on day 7 based on microscopy and nested PCR analysis, respectively. However, there was an increase in parasite prevalence from day 14 to day 42, with a subsequent decline on day 70 by both microscopy and nested PCR. For parasite clearance rate analysis, we found a significant proportion of the participants harbouring residual Plasmodium parasites or parasite genomic DNA on day 1 [65.0% (13/20)], day 2 [65.0% (13/20)] and day 3 [60.0% (12/20)] after initiating treatment. Of note, gametocyte carriage among participants was low before and after treatment.ConclusionTaken together, the results indicate that a significant number of individuals could harbour residual Plasmodium parasites or parasite genomic DNA after treatment. The study demonstrates the importance of routine surveillance of asymptomatic malaria using sensitive nucleic acid-based amplification techniques.

One biomarker does not fit all: tailoring anti-infective therapy through utilization of procalcitonin and other specific biomarkers

ABSTRACT Introduction Considering the ongoing increase in antibiotic resistance, the importance of judicious use of antibiotics through reduction of exposure is crucial. Adding procalcitonin (PCT) and other biomarkers to pathogen-specific tests may help to further improve antibiotic therapy algorithms and advance antibiotic stewardship programs to achieve these goals. Areas covered In recent years, several trials have investigated the inclusion of biomarkers such as PCT into clinical decision-making algorithms. For adult patients, findings demonstrated improvements in the individualization of antibiotic treatment, particularly for patients with respiratory tract infections and sepsis. While most trials were performed in hospitals with central laboratories, point-of-care testing might further advance the field by providing a cost-effective and rapid diagnostic tool in upcoming years. Furthermore, novel biomarkers including CD-64, presepsin, Pancreatic stone and sTREM-1, have all shown promising results for increased accuracy of sepsis diagnosis. Availability of these markers however is currently still limited and there is insufficient evidence for their routine use in clinical care. Expert opinion In addition to new host-response markers, combining such biomarkers with pathogen-directed diagnostics present a promising strategy to increase algorithm accuracy in differentiating between bacterial and viral infections. Recent advances in microbiologic testing using PCR or nucleic amplification tests may further improve the diagnostic yield and promote more targeted pathogen-specific antibiotic therapy.

210.7: Undetectable Recipient COVID-19 Plasma PCR Following COVID-19 Positive Donor Kidney Transplant: Proof of Concept Analysis

Introduction: With one-third of the United States still not fully vaccinated for COVID-19 and almost one-half unvaccinated in Arkansas, it is common to see patients presenting with non-survivable diagnosis, incidentally testing COVID-19+ or with recent history of mild COVID-19 infection. In the absence of COVID-19, such patients could become organ donors. Limited case series have demonstrated no COVID-19 syndrome following transplantation from such donors. However, hematogenous asymptomatic transmission of the COVID-19 virus following transplant remains unclear. Aim of this study was to assess COVID-19 virus presence in the recipient’s bloodstream at the early post-transplant period following COVID-19+ organ transplantation. Methods: An institutional protocol was drafted for the use of COVID-19+ donor organs. Eligible donors included those test COVID-19+, however with cause of death not related to COVID-19, and no evidence of moderate to severe COVID-19. Eligible recipients included those who tested negative for COVID-19 at the time of transplant, had been fully vaccinated against COVID-19, and consented to receive such organs. A protocol deviation occurred when a COVID-19+ organ was transplanted into a non-vaccinated recipient with recent history of resolved COVID-19 infection. Plasma was drawn to test for COVID-19 polymerase chain reaction (PCR) prior to hospital discharge post-transplant. All recipients received tixagevimab-cilgavimab (Evusheld) after plasma COVID-19 PCR testing. Results: Six recipients underwent kidney transplantation from COVID-19+ donors. One donor had reported mild symptoms of COVID-19 prior to hospitalization. Two donors tested Hepatitis C positive by nucleic amplification testing. 83.3% (N=5) of recipients were fully vaccinated prior to transplant (Table 1). An additional recipient had not been vaccinated but had history of recent COVID-19 infection. None of the recipients developed COVID-19 symptoms post-transplant. All had undetectable serum plasma COVID-19 PCR prior to discharge (testing range post-operative day 2 to 5). Post-transplant median length of stay was 3 days. Median follow-up was 39 days (33, 62). Two recipients had delayed renal allograft function. One patient developed antibody-mediated rejection diagnosed on post-operative day 30. No recipients required post-transplant testing for suspected COVID-19 symptoms. There was no mortality (Table 2). Discussion: This case series provides proof of concept that there is no evidence of hematogenous transfer of COVID-19 from donor positive organs to recipients immune to the virus. Therefore, otherwise transplantable organs from donors incidentally diagnosed with COVID-19 at the time of donation, with no indication of severe COVID-19 disease at the time of donation, should be considered for non-thoracic organ transplantation to suitable recipients, after appropriate consenting.

Current status of rapid bacterial detection methods for platelet components: A 20-year review by the ISBT Transfusion-Transmitted Infectious Diseases Working Party Subgroup on Bacteria.

Bacterial contamination of platelet components (PCs) poses a safety challenge for transfusion patients. Despite mitigation interventions, the residual risk of transfusion-transmitted bacterial infections remains predominant. PC safety can be improved either by pathogen reduction or by implementation of bacterial detection methods. Detection methodologies include culture methods and rapid detection methods. The current review focuses on currently available rapid detection methods. We reviewed published manuscripts since 2000 on rapid bacterial detection methods used for PC screening with result determination within 4 h. Methods meeting this criterion included Verax PGDprime, BacTx and nucleic amplification testing. The analytical and diagnostic sensitivity and specificity of these systems were assessed. The analytical sensitivity between the different detection methods ranged between 50 and 100,000 CFU/ml. The sample volume used by these testing systems varies between 0.5 and 1.0ml of PCs. A delay of at least 48 h before sampling enhances detectability. All rapid detection methods generate results in a timely manner, allowing testing to be performed before transfusion with optimal sensitivity. Rapid detection methods improve PC safety regarding bacterial contamination. The assays are optimal for rapidly growing bacteria, which are more likely to cause septic transfusion reactions in patients. Because of the reduced diagnostic sensitivity, the sample collection should be late in shelf-life and ideally just before transfusion. The major benefit of these methods is that the test result can be obtained before releasing PCs for transfusion or to be used in combination with other screening methods applied early during PC storage.

Cardiac Allograft Vasculopathy in Heart Transplant Recipients from Hepatitis C Viremic Donors, Data from Two Large Academic Transplant Centers

<h3>Purpose</h3> Heart transplantation from Hepatitis C (HCV) viremic donors is an increasingly utilized strategy, though long-term outcomes with respect to cardiac allograft vasculopathy (CAV) are unknown. HCV is implicated as a potent trigger of the inflammatory cascade and may be associated with CAV. We report the incidence of CAV and subclinical disease in recipients of HCV-viremic donors (nucleic amplification test positive: NAT+) vs non-viremic donors (nucleic amplification test negative: NAT-) <h3>Methods</h3> We retrospectively reviewed coronary angiograms with intravascular ultrasound (IVUS) of patients who received NAT+ and NAT- hearts between January 2014 and July 2020 at two large academic institutions. Donor-derived acute HCV infection was treated with a direct-acting antiviral agent per site protocol. CAV was graded according to ISHLT guidelines. Maximal intimal thickness (MIT) of the left main and left anterior descending artery was measured by IVUS. MIT ≥ 0.5mm was considered significant subclinical disease. Two-sample t tests were performed for continuous variables. Chi-square or Fisher's exact test were used for categorical variables. <h3>Results</h3> Among 178 patients, 65 received NAT+ donor hearts. Average recipient age was 58 and 55 years in the NAT+ and NAT- groups respectively and 15% vs 27% were female. NAT- donors were older (42 vs 36 years), but with no significant difference in cardiac risk factors including tobacco use, hypertension, and diabetes. CAV ≥ grade 1 was present in 9.1% of the NAT+ vs 18.8% of the NAT- group at 1 year (p=0.16), and 19.4% vs 21.0% at 2 years (p=1). Rates of significant IVUS disease were 53.7% in NAT+ vs 70.5% in NAT- at 1 year (p=0.068), and 72.2% vs 78.3% at 2 years (p=0.3). <h3>Conclusion</h3> Among heart transplant recipients from HCV viremic donors our data show no difference in rates of angiographic CAV or subclinical disease by IVUS at 1 or 2 years. While these results are encouraging, longer follow up is needed to assess CAV risk in this population.

Performance of Abbott ID-Now rapid nucleic amplification test for laboratory identification of COVID-19 in asymptomatic emergency department patients.

ObjectiveWe sought to evaluate the test characteristics of Abbott ID‐Now as a screening tool compared to polymerase chain reaction (PCR) testing for identification of COVID in an asymptomatic emergency department population.MethodsWe performed a prospective study enrolling a convenience sample of asymptomatic patients presenting to a single academic emergency department (ED) who received simultaneous testing with ID‐Now and PCR per standardized ED protocols. Sensitivity, specificity, and positive and negative predictive value (PPV, NPV) of ID‐Now were calculated compared to PCR. Stratified analysis by cycle threshold (Ct) values was also performed, defined as high viral load (Ct < 33) and low viral load (Ct ≥ 33).ResultsA total of 3121 patients were enrolled, of whom 2895 had valid results for ID‐Now and PCR. COVID prevalence was 2.6%. ID‐Now had a sensitivity of 85.1% (95% CI 75.9% to 92.7%) and a specificity of 99.7% (99.5% to 99.9%). PPV and NPV were high at 87.5% (83.1% to 96.1%) and 99.6% (99.3% to 99.8%). Stratified analysis by low and high Ct values demonstrated reduction in sensitivity in patients with low viral loads: 91.7% (81.6% to 97.2%) in low Ct value patients versus 58.3% (27.7% to 84.8%) in high Ct value patients.ConclusionsID‐Now had excellent performance in asymptomatic ED patients with a low rate of false positives. Cycle threshold analysis suggests a relationship between viral load and ID‐Now sensitivity. Given its speed and performance in this population, ID‐Now should be considered an excellent tool to support clinical decision‐making in ED populations.

Detection of Treponema pallidum DNA in Oropharyngeal Swabs and Whole Blood for Syphilis Diagnosis.

Syphilis diagnosis relies on serological tests, which may be falsely nonreactive or may be reactive but not reflect current syphilis. Polymerase chain reaction for detection of T. pallidum DNA was performed on 123 oropharyngeal swabs, 120 whole bloods, and 46 lesion exudate swabs from 123 untreated individuals with syphilis (cases); oropharyngeal swabs from 148 at-risk controls without syphilis; and 73 oropharyngeal swabs and 36 whole bloods from 73 individuals recently treated for syphilis. Most (90.2%) cases had early syphilis. T. pallidum DNA was detected in 33 (26.8%) of 123 oropharyngeal swabs, 32 (26.7%) of 120 bloods, and 30 (65.2%) of 46 lesion exudate swabs. T. pallidum DNA was detected in 49 (40.8%) of 120 individuals in whom both oropharyngeal swabs and blood were tested. T. pallidum was more likely to be amplified from oropharyngeal swabs when it was amplified from blood than when it was not (15 of 32 [46.9%] vs. 17 of 88 [19.3%], P = 0.003). For each 2-fold increase in serum rapid plasma reagin titer, the odds of detection of T. pallidum DNA in oropharyngeal swabs increased by 1.44 (95% confidence interval, 1.14-1.82, P = 0.003). T. pallidum DNA was not detected in oropharyngeal samples from controls, but it was detected in 3 (8.3%) of 36 bloods from individuals recently treated for syphilis: 2 at 1 day and 1 at 5 days after initiation of syphilis treatment. Nucleic amplification tests can identify recent T. pallidum infection and may be particularly useful for diagnosis of very early or asymptomatic syphilis.

Cardiac Allograft Vasculopathy in Heart Transplant Recipients from Hepatitis C Viremic Donors

Heart transplantation from Hepatitis C (HCV) viremic donors is becoming increasingly used due to advent of direct acting antiviral drugs with almost 100% cure. There are limited data about its impact on cardiac allograft vasculopathy (CAV). We report the incidence of CAV in heart transplant recipients from HCV viremic donors (nucleic amplification test positive; NAT+) compared to non-HCV infected donors (NAT-). We retrospectively reviewed coronary angiograms with intravascular ultrasound (IVUS) of heart transplant recipients at our institution from January 5, 2018 to September 17, 2019. The presence of CAV was graded according to ISHLT guidelines. IVUS was performed as per our lab protocol on the left main and left anterior descending arteries. Maximal intimal thickness (MIT) was measured with advanced quantification software as per protocol. MIT ≥ 5mm was considered significant for future adverse outcomes. LHC and IVUS was performed on 24 heart transplant recipients (mean age 56; 70% male) at 1- year post transplant. Eleven of these patients were transplanted from NAT+ donors. Thirteen patients received a NAT- donor heart. Two recipients (18.7%) of NAT+ donors had CAV grade ≥ 1 compared to 2 (16.7%) from NAT- donors (p=1). MIT ≥ 5mm was seen in 88.9% of NAT+ vs 50% of NAT- recipients (p=0.14) (Figure). The mean MIT was 76mm and 65mm for NAT+ and NAT- group, respectively. Both NAT+ and NAT- donor recipients exhibit mostly eccentric (84.2%) and few (15.7%) demonstrated concentric plaques. There was no heterogeneity in the data after adjusting for risk factors for CAD and donor LHC. Our data show no difference in the presence of (CAV ≥ grade 1) or subclinical atherosclerosis at 1 year among NAT+ donor recipients. HCV viremia is a known risk factor for accelerated atherosclerosis and the consequence of prolonged donor viremia on the recipient is not known. A larger cohort and further longitudinal follow-up is needed to assess the validity of this trend and its prognostic implications.

Incidence of Acute Cellular Rejection in Heart Transplant Recipients from Hepatitis C Viremic Donors – One-Year Follow-Up

Passive transmission of hepatitis C (HCV) viremia from actively infected donors to uninfected recipients at the time of heart transplantation may modulate response to alloantigens and risk of allograft rejection. We evaluated the one-year incidence of acute cellular rejection (ACR) in patients transplanted from nucleic amplification testing positive (NAT+) HCV donors compared to those from NAT negative (NAT-) donors. Since January 2018, 25 patients completed one-year follow-up. All recipients underwent right ventricular endomyocardial biopsy (EMB) per our institution protocol. ACR was graded according to both the 1990 and the revised 2004 International Society for Heart and Lung Transplantation (ISHLT) criteria. All NAT+ donor recipients developed viremia detected by RT-PCR. Mixed models were used to assess the association between donor HCV NAT status, recipient viremia, tacrolimus levels and ACR in the first year post-transplant. Twelve NAT+ recipients (mean age 60, 67% male) and 13 NAT- recipients (mean age 54, 77% male) completed one-year follow-up; 182 and 191 EMB were performed, respectively. NAT+ recipients were associated with higher grade rejection compared with NAT- recipients (p=0.041). At least one episode of high grade rejection (2R/3A) occurred in 4 NAT+ recipients (33%) compared with 2 NAT- recipients (15%). At least one episode of low grade rejection (1R/1B or 1R/2) occurred in 11 NAT+ recipients (92%) compared with 7 NAT- recipients (54%). These findings were independent of the presence and magnitude of viremia and tacrolimus levels. No episodes of ACR 3R or antibody mediated rejection were detected during one-year follow-up in either group. There was no allograft dysfunction or mortality related to ACR in either group. One year data from our institution demonstrate increased ACR in heart transplant recipients from NAT+ donors. Most of the rejection episodes in the NAT+ group were low grade and did not translate into any adverse outcomes through one-year follow-up.

1299. Cluster of False-Positive “Fifth-Generation” HIV Test Results During Implementation of a Routine HIV Screening Program in an Emergency Department

BackgroundIn November 2014, the University of Illinois Hospital (UI Health) introduced an electronic medical record (EMR)-driven HIV screening program in the emergency department (ED). In October 2016, our hospital laboratory introduced “Fifth-generation” HIV testing using the Bio-Rad BioPlex 2200 HIV Antigen/Antibody diagnostic assay. Fifth-generation HIV testing has the advantage of separately detecting and reporting HIV antibody and HIV-1 p24 antigen. Although the literature and manufacturer report high sensitivity and specificity of this test, we encountered higher than expected rates of false-positive tests during the introduction of this test.MethodsWe retrospectively reviewed the results of our ED HIV screening program from October 2016 to March 2019 to describe the outcomes of HIV testing, determine the rates of false-positive HIV tests and determine if false-positive rates were temporally clustered. We also investigated various potential causes of higher than expected false positives including pre-analytical and analytical error. We defined a false-positive test as a repeatedly reactive initial HIV antigen and/or HIV-1 antibody result with a subsequent negative or indeterminate HIV-1/2 antibody differentiation immunoassay and negative HIV-1 nucleic amplification test.ResultsDuring the review period, out of a total of 17,385 HIV tests which were performed, 85 tests were confirmed positive and 27 were false positives. This represents an HIV prevalence of 0.5%. Eighteen of the 27 false positives occurred during an 8 month period between October 2016 and April 2017 (see Figure 1). During our investigation of potential causes of the false-positive tests, we discovered that a reagent lot for the test was changed in June 2017 which resulted in a significant decrease in the false-positive rate (0.33% to 0.07%).ConclusionWe provide data which suggests that a reagent lot may have been the cause of higher than expected false-positive tests for HIV testing. Monitoring of testing outcomes during implementation of a routine HIV testing program can help identify potential root causes of false-positive tests. Disclosures All authors: No reported disclosures.

Does the Sex Risk Quiz Predict Mycoplasma genitalium Infection in Urban Adolescents and Young Adult Women?

Mycoplasma genitalium (MG) is a common sexually transmitted infection (STI), but there are limited strategies to identify individuals at risk of MG. Previously, a sex risk quiz was used to predict STIs including Chlamydia trachomatis, Neisseria gonorrhoeae, and/or Trichomonas vaginalis. The original quiz categorized individuals 25 years or younger as at risk of STIs, but the Centers for Disease Control and Prevention identifies females younger than 25 years as at risk of STIs. In this study, the quiz was changed to categorize females younger than 25 years as high risk. The objective was to determine if the age-modified risk quiz predicted MG infection. A cross-sectional analysis of a prospective longitudinal study was performed including female adolescents and young adults (AYAs) evaluated in multiple outpatient clinics. Participants completed an age-modified risk quiz about sexual practices. Scores ranged from 0 to 10 and were categorized as low risk (0-3), medium risk (4-7), and high risk (8-10) based on the STI prevalence for each score. Vaginal and/or endocervical and/or urine specimens were tested for MG, T. vaginalis, C. trachomatis, and N. gonorrhoeae using the Aptima Gen-Probe nucleic amplification test. There were 693 participants. Most participants reported having 0 to 1 sexual partners in the last 90 days (91%) and inconsistent condom use (84%). Multivariable logistic regression analysis controlling for race, education, and symptom status demonstrated that a medium-risk score predicted MG infection among AYAs younger than 25 years (adjusted odds ratio, 2.56 [95% confidence interval, 1.06-6.18]). A risk quiz may be useful during clinical encounters to identify AYA at risk of MG.

Diagnosis and treatment of histoplasmosis in solid organ transplant patients.

Unlike immunocompetent hosts, solid organ transplant (SOT) recipients with posttransplant histoplasmosis (PTH) often present with disseminated disease and have an attributable mortality of approximately 10%. In this review, we discuss currently available diagnostic tests and treatment strategies in PTH. None of the available tests have a 100% diagnostic accuracy. Histoplasma antigen assays are the most sensitive commercially available tests. However, crossreactivity of histoplasma antigen with aspergillus galactomannan and false positive histoplasma antigen tests because of rabbit antithymocyte globulin may cause difficulty in interpreting positive test results in transplant recipients. Molecular assays such as amplification and sequencing of 'panfungal' portions of the 28S ribosomal RNA from clinical specimens appear to be promising.Lipid formulations of amphotericin B and itraconazole are the drugs of choice in the treatment of PTH. Other extended spectrum azoles also appear to be effective, but, like itraconazole, problems with drug interactions and prolongation of the QTc interval (except for isavuconazole, which shortens the QTc interval) remain. Mycophenolate therapy is associated with severe disease and should be stopped during active disease and, if feasible, calcineurin inhibitors and steroids should be reduced. A combination of various tests (culture, antigen tests, nucleic amplification tests, etc.) should be used to optimize diagnostic yield. The role of unbiased next generation sequencing for early diagnosis and newer azoles in the treatment needs to be further explored.

Laboratory Impact of Rapid Molecular Tests used for the Detection of Respiratory Pathogens

With outbreaks of new respiratory viruses such as the severe acute respiratory syndrome coronavirus and swine-origin influenza A/H1N1, the nucleic acid-based amplification test was introduced to identify causative agents. Multiplex PCR, which can simultaneously detect various respiratory pathogens, is currently used worldwide. Recently, a new type of multiplexed molecular test using a fully automated workflow system was developed, which was also adapted to our laboratory. In this study, we assessed improvements in laboratory practice brought about by the implementation of the rapid test for the detection of respiratory viruses. We investigated the number of routine and rapid tests conducted as well as the change in monthly test frequency of the routine test. We also analyzed the waiting time, turnaround time, and lead time for the routine and rapid tests. The Anyplex II RV16 detection kit (Seegene, Seoul, Korea) and Filmarray Respiratory Panel (BioFire Diagnostics, Inc., Salt Lake City, UT, USA) were used for the routine and rapid tests, respectively. Compared to the routine test, the rapid test significantly (p < 0.01) decreased the mean waiting time (1 hour 46 minutes), turnaround time (1 hour 45 minutes), and lead time (3 hours 32 minutes). After the implementation of the rapid test, the number of routine tests conducted was reduced over the 5-month period, from 13 times a month to 3 times a month. The implementation of the rapid test for the detection of respiratory viruses improved the diagnostic efficiency of the laboratory and greatly reduced lead time.

Immuno-diagnosis of Mycobacterium tuberculosis in sputum, and reduction of timelines for its positive cultures to within 3\xa0h by pathogen-specific thymidylate kinase expression assays

BackgroundLaboratory diagnosis of Tuberculosis (TB) is traditionally based on microscopy and or culture. Microscopy is however, only sensitive to a specified degree of bacillary load not present in HIV co-infected persons. Traditional cultures of Mycobacterium tuberculosis (M. tb), on the other hand, take weeks to read—thereby delaying the critical decision whether or not, to treat. Although nucleic acids amplification tests (NAATS) applied directly on sputum or cultures can increase the sensitivity for TB diagnosis among those with HIV co-infection as well as reduce time-lines for positive culture detection, they do not replace the need for smear microscopy and culture. We have previously proposed the M. tb DNA-synthetic enzyme thymidylate kinase (aka TMKmt) as an organism-specific growth and proliferation biomarker to reduce time-lines for detection of positive TB cultures. In this study, we explored the secretory levels of TMKmt in M. tb cultures and sputum, towards improving the overall laboratory diagnosis of TB.Methods and resultsModelling of TMKmt secretion in vitro was done by cloning, expressing and SDS-PAGE/MALDI-TOF detection of purified recombinant TMKmt in E. coli. TMKmt expression profiling in M. tb was done by qRT-PCR assay of related messenger ribonucleic acids (mRNA) and TMKmt antigen detection by Enzyme linked Immuno-absorbent Assay (EIA) among cultures of a pathogenic wild-type Ugandan strain (genotype 1) alongside the H37Rv laboratory strain. Owing to the high-load of pathogen in-culture, direct EIA on limiting dilutions of sputum were done to examine for assay sensitivity. A rise in TMKmt antigen levels was observed at 3 h post-innoculation among in vitro cultures of E. coli. The 1st of several cyclic spikes in TMKmt mRNA and antigen levels were detected at 2.5 h among in vitro cultures of the pathogenic wild-type Ugandan isolate alongside the laboratory M. tb strain. TMKmt antigen was detected up to between 1 × 10−4–1 × 10−5 (containing 10 and 1 CFUs/ml) dilutions of a microscopically designated 1+ (est. Acid Fast Bacillary load of 1 × 105) patient sample.ConclusionsDetection of TMKmt expressed mRNA and Ag offers us opportune for instant diagnosis of M. tb in sputum, and reduction of timelines for positive pathogen detection in cultures to within 3 h.

The Diagnosis of Nongonococcal Urethritis in Men: Can There Be a Universal Standard?

The Diagnosis of Nongonococcal Urethritis in Men: Can There Be a Universal Standard?