Browsing by Author "Emery, Christopher L."

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    582. Comparing Broad-range PCR Testing and The Biofire® FilmArray® Pneumonia (PN) Panel in the Diagnosis of Bacterial Pneumonia
    (Oxford University Press, 2023-11-27) Khan, Haseeba; Prabhudas-Strycker, Kirsten; Samaro, Matthew; Mellencamp, Kagan A.; Goings, Michael; Boyd, LaKeisha; Schneider, Jack; Emery, Christopher L.; Pediatrics, School of Medicine
    Background: Given the low sensitivity of conventional microbial isolation methods for identifying respiratory pathogens in bacterial pneumonia, target-specific syndromic multiplex real-time PCR panels have been used in conjunction with culture methods to improve diagnostic yield. Additionally, broad-range polymerase chain reaction (BR-PCR) targeting bacterial 16s rRNA conserved region has shown higher sensitivity with certain specimen types, so we sought to evaluate the clinical performance of BR-PCR performed on bronchoalveolar lavage (BAL) specimens in comparison to The Biofire® FilmArray® Pneumonia (PN) Panel (BioFire Diagnostics, Salt Lake City, UT, USA). Methods: A retrospective chart review was performed on all BAL specimens that had both a PN panel test and BR-PCR performed from January 2020 to May 2022 at all Indiana University affiliated hospitals. The PN panel test was performed in-house as per laboratory protocol, while BR-PCR was performed in a reference laboratory. Outcomes assessed included turn-around times (TAT), sensitivity and specificity of BR-PCR and clinical impact, if any. Results: A total of 68 BAL specimens from 53 patients were identified (83% of patients were immunocompromised). Percent positivity for the PN panel was 19% and that of BR-PCR was 18%. With the PN panel used as the gold standard, the sensitivity and specificity of BR-PCR was 85% and 98%, respectively. Only one respiratory organism was detected by BR-PCR but not by the PN panel, and it was not considered pathogenic or to have a significant clinical impact. The median TAT for the PN panel was 2.1 hours (1.8, 3.2) versus 7.8 days (6.9, 10.4) for BR-PCR. Conclusion: In our cohort of patients, BR-PCR testing was not superior to the Biofire® FilmArray® Pneumonia (PN) Panel when used to detect certain bacterial etiologies of pneumonia. Additionally, faster TAT for the panel test has the potential to enhance antimicrobial stewardship practices by enabling better antibiotic utilization. Adjunctive BR-PCR testing may be useful for clinical care when conventional testing is negative and patients are at risk for a variety of potential pathogens, including fungi.
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    Comparison of Four Commercially Available Group B Streptococcus Molecular Assays Using Remnant Rectal-Vaginal Enrichment Broths
    (Elsevier, 2018) Relich, Ryan F.; Buckner, Rebecca J.; Emery, Christopher L.; Davis, Thomas E.; Pathology and Laboratory Medicine, School of Medicine
    The incidence of neonatal Group B streptococcal (GBS) disease has significantly declined since the widespread implementation of prenatal screening of expectant mothers for urogenital and gastrointestinal tract GBS colonization. Screening methods have evolved from exclusively culture-based approaches to more rapid and highly sensitive molecular methods. We chose to evaluate the performance of four commercially available GBS molecular tests for detection of GBS colonization using 299 antepartum rectal-vaginal specimens submitted to our laboratory for routine GBS screening. In 97% of instances, there was agreement between all three systems. When testing 1, 6, and 12 samples simultaneously, all methods performed comparably, but the ARIES® GBS assay required the least total hands-on time and the illumigene® Group B Streptococcus assay required the most hands-on time.
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    Direct antimicrobial susceptibility testing of positive blood cultures: A comparison of the accelerate Pheno™ and VITEK® 2 systems
    (Elsevier, 2019) Schneider, Jack G.; Wood, James B.; Smith, Nathan W.; Emery, Christopher L.; Davis, Thomas E.; Manaloor, John J.; Bocian, Brittany; Schmitt, Bryan H.; Medicine, School of Medicine
    Objectives To compare the performance and time-to-result (TTR) for antimicrobial susceptibility testing (AST) of positive blood cultures (PBC) using the Accelerate Pheno™ system (AXDX) and both a direct VITEK® 2 card inoculation workflow (DV2) and traditional FDA-approved VITEK® 2 workflow using subcultured isolates (V2). Methods Patient samples with monomicrobial Gram-negative rod bacteremia were tested on AXDX and DV2 in tandem, and compared to V2 AST results. Categorical agreement (CA) errors were adjudicated using broth microdilution. Instrumentation times and AST TTR were compared. Results AXDX and DV2 had a CA of 91.5% and 97.4%, respectively, compared to V2. Post-adjudication, AXDX, DV2, and V2 had CA of 94.7%, 95.7% and 96.5%, respectively. Instrument run times were 6.6 h, 9.4 h, and 9.2 h, and AST TTR were 8.9 h, 12.9 h and 35.5 h, respectively. Conclusions AXDX and DV2 AST is fast and reliable, which may have significant antimicrobial stewardship implications.
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    Molecular characterization of β-lactamase genes in clinical isolates of carbapenem-resistant Acinetobacter baumannii
    (BMC, 2017-11-16) Raible, Kevin M.; Sen, Bhaswati; Law, Nancy; Bias, Tiffany E.; Emery, Christopher L.; Ehrlich, Garth D.; Joshi, Suresh G.; Pathology and Laboratory Medicine, School of Medicine
    Background Acinetobacter baumannii is a nosocomial pathogen which is establishing as a major cause of morbidity and mortality within the healthcare community. The success of this pathogen is largely due to its ability to rapidly gain resistance to antimicrobial therapies and its capability to persist in an abiotic environment through the production of a biofilm. Our tertiary-care hospital has showed high incidence of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates. Methods In this study we explore both genotypic and phenotypic properties of 26 CRAB isolates: 16 isolates were collected from January 2010 to March 2011, and 10 were collected between February and May 2015. Results We determined that all 26 CRAB isolates possessed multiple β-lactamase genes, including genes from Groups A, C, and D. Specifically, 42% of the isolates possesses the potentially plasmid-borne genes of OXA-23-like or OXA-40-like β-lactamase. The presence of mobile gene element integron cassettes and/or integrases in 88% of the isolates suggests a possible mechanism of dissemination of antibiotic resistance genes. Additionally, the location of insertion sequence (IS) ISAba1 in promotor region of of the OXA-51-like, ADC-7, and ampC genes was confirmed. Multilocus sequence typing (MLST) demonstrated that all 26 CRAB isolates were either sequence type (ST)-229 or ST-2. Interestingly, ST-2 went from being the minority CRAB strain in the 2010–2011 isolates to the predominant strain in the 2015 isolates (from 32 to 90%). We show that the ST-2 strains have an enhanced ability to produce biofilms in comparison to the ST-229 strains, and this fact has potentially led to more successful colonization of the clinical environment over time. Conclusions This study provides a longitudinal genetic and phenotypic survey of two CRAB sequence types, and suggests how their differing phenotypes may interact with the selective pressures of a hospital setting effecting strain dominance over a 5-year period. Electronic supplementary material The online version of this article (10.1186/s12941-017-0248-3) contains supplementary material, which is available to authorized users.
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    Moraxella canis induced sepsis from dog's lick
    (Elsevier, 2022-01-10) Padanilam, Mathew S.; Qasim, Muhammad; Emery, Christopher L.; Pathology and Laboratory Medicine, School of Medicine
    Moraxella canis was first identified in 1993 as normal flora of the oral cavities of dogs and cats. The species has been reported to cause localized infections in immunocompromised humans only three times. We report the first description of severe disseminated infection attributed to M. canis.
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    Multicenter Clinical Evaluation of ETEST Eravacycline for Susceptibility Testing of Enterobacteriaceae and Enterococci
    (American Society for Microbiology, 2023) Blanchard, Laurine S.; Armstrong, Thomas P.; Kresken, Michael; Emery, Christopher L.; Ying, Yun X.; Sauvonnet, Véronique; Zambardi, Gilles; Pathology and Laboratory Medicine, School of Medicine
    Eravacycline (ERV) (brand name Xerava [Tetraphase]) is a new tetracycline-class antibacterial that has been approved by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for treatment of complicated intra-abdominal infections (cIAIs). ETEST is a gradient diffusion method that represents a simple alternative to the broth microdilution (BMD) method for performing antimicrobial susceptibility testing (AST). A multicenter evaluation of the performance of the new ETEST ERV (bioMérieux) in comparison with BMD was conducted following FDA and International Standards Organization (ISO) recommendations, using FDA- and EUCAST-defined breakpoints. Clinical isolates of Enterobacteriaceae (n = 542) and Enterococcus spp. (n = 137) were included. Based on the BMD reference method, 92 Enterobacteriaceae isolates and 9 enterococcal isolates were nonsusceptible to ERV according to the FDA breakpoints, while 7 Escherichia coli isolates and 3 Enterococcus sp. isolates were classified as ERV resistant according the EUCAST breakpoints. Referring to FDA performance criteria, the ETEST ERV demonstrated 99.4% and 100.0% essential agreement (EA), 98.0% and 94.9% categorical agreement (CA), very major error (VME) rates of 5.4% and 33.33%, and major error (ME) rates of 1.3% and 3.1% with clinical and challenge isolates, respectively, of Enterobacteriaceae and Enterococcus spp. According to EUCAST breakpoints, E. coli and Enterococcus sp. isolate results also met ISO acceptance criteria for EA and CA (EA of 99.0% and 100.0%, respectively, and CA of 100.0% for both), without any VMEs or MEs. In conclusion, we report that ETEST ERV represents an accurate tool for performing ERV AST of Enterobacteriaceae and Enterococcus sp. isolates.
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    Multicenter Clinical Evaluation of ETEST Plazomicin (PLZ) for Susceptibility Testing of Enterobacterales
    (American Society for Microbiology, 2022) Blanchard, Laurine S.; Van Belkum, Alex; Dechaume, Dominique; Armstrong, Thomas P.; Emery, Christopher L.; Ying, Yun X.; Kresken, Michael; Pompilio, Marion; Halimi, Diane; Zambardi, Gilles; Pathology and Laboratory Medicine, School of Medicine
    Plazomicin (PLZ), brand name ZEMDRI (Cipla Therapeutics), is a novel aminoglycoside antibiotic approved by the U.S. Food and Drug Administration (FDA) for treatment of complicated urinary tract infections including pyelonephritis. ETEST® is a gradient diffusion method that represents an alternative to the more laborious broth micro-dilution (BMD) method for performing antimicrobial susceptibility testing (AST). A multi-center evaluation of the performance of the new ETEST PLZ (bioMérieux) was conducted in comparison with BMD following FDA and International Standards Organization (ISO) recommendations using FDA-defined breakpoints. Clinical isolates of Enterobacterales (n = 598) were included. Fifty-three isolates were resistant to PLZ according to BMD. Overall, the ETEST PLZ demonstrated 99.0% essential agreement (EA), 92.8% category agreement (CA), 1.9% very major errors (VME), 0% major errors (ME), and 7.0% minor errors (mE) with both clinical and challenge isolates of Enterobacterales. The VME was found for a single Serratia marcescens strain. Individual species demonstrated EA rates ≥ 90%. In conclusion, we report that ETEST PLZ represents an accurate tool for performing PLZ AST of Enterobacterales.
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    Standardization of SARS-CoV-2 Cycle Threshold Values: Multisite Investigation Evaluating Viral Quantitation across Multiple Commercial COVID-19 Detection Platforms
    (ASM, 2023-01) Gavina, Kenneth; Franco, Lauren C.; Robinson, Christopher M.; Hymas, Weston; Lei, Guang-Sheng; Sinclair, Will; Hall, Tara; Carlquist, John; Lavik, John-Paul; Emery, Christopher L.; Heaton, Phillip R.; Hillyard, David; Lopransi, Bert K.; Relich, Ryan F.; Pathology and Laboratory Medicine, School of Medicine
    The demand for testing during the coronavirus disease 2019 (COVID-19) pandemic has resulted in the production of several different commercial platforms and laboratory-developed assays for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This has created several challenges, including, but not limited to, the standardization of diagnostic testing, utilization of cycle threshold (CT) values for quantitation and clinical interpretation, and data harmonization. Using reference standards consisting of a linear range of SARS-CoV-2 concentrations quantitated by viral culture-based methods and droplet digital PCR, we investigated the commutability and standardization of SARS-CoV-2 quantitation across different laboratories in the United States. We assessed SARS-CoV-2 CT values generated on multiple reverse transcription-PCR (RT-PCR) platforms and analyzed PCR efficiencies, linearity, gene targets, and CT value agreement. Our results demonstrate the inappropriateness of using SARS-CoV-2 CT values without established standards for viral quantitation. Further, we emphasize the importance of using reference standards and controls validated to independent assays, to compare results across different testing platforms and move toward better harmonization of COVID-19 quantitative test results.
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    Susceptibility Provision Enhances Effective De-escalation (SPEED): utilizing rapid phenotypic susceptibility testing in Gram-negative bloodstream infections and its potential clinical impact
    (Oxford Academic, 2019-01-01) Schneider, Jack G.; Wood, James B.; Schmitt, Bryan H.; Emery, Christopher L.; Davis, Thomas E.; Smith, Nathan W.; Blevins, Sarah; Hiles, Jon; Desai, Armisha; Wrin, Justin; Bocian, Brittany; Manaloor, John J.; Medicine, School of Medicine
    Abstract Objectives We evaluated the performance and time to result for pathogen identification (ID) and antimicrobial susceptibility testing (AST) of the Accelerate Pheno™ system (AXDX) compared with standard of care (SOC) methods. We also assessed the hypothetical improvement in antibiotic utilization if AXDX had been implemented. Methods Clinical samples from patients with monomicrobial Gram-negative bacteraemia were tested and compared between AXDX and the SOC methods of the VERIGENE® and Bruker MALDI Biotyper® systems for ID and the VITEK® 2 system for AST. Additionally, charts were reviewed to calculate theoretical times to antibiotic de-escalation, escalation and active and optimal therapy Results ID mean time was 21 h for MALDI-TOF MS, 4.4 h for VERIGENE® and 3.7 h for AXDX. AST mean time was 35 h for VITEK® 2 and 9.0 h for AXDX. For ID, positive percentage agreement was 95.9% and negative percentage agreement was 99.9%. For AST, essential agreement was 94.5% and categorical agreement was 93.5%. If AXDX results had been available to inform patient care, 25% of patients could have been put on active therapy sooner, while 78% of patients who had therapy optimized during hospitalization could have had therapy optimized sooner. Additionally, AXDX could have reduced time to de-escalation (16 versus 31 h) and escalation (19 versus 31 h) compared with SOC. Conclusions By providing fast and reliable ID and AST results, AXDX has the potential to improve antimicrobial utilization and enhance antimicrobial stewardship.
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    The Brief Case: Suspicious Gram-Negative Coccobacilli-Francisella tularensis subsp. novicida Isolated from an Immunocompromised Patient
    (American Society for Microbiology, 2023) Gavina, Kenneth; Whitacre, Brynne E.; Meyer, Thomas L.; Van Benten, Kayla; Glazier, Mark; Emery, Christopher L.; Lavik, John-Paul; Relich, Ryan F.; Pathology and Laboratory Medicine, School of Medicine