Browsing by Author "Chambers, Henry F"

Filter results by typing the first few letters
Now showing 1 - 8 of 8
  • Thumbnail Image
    ItemOpen Access
    A Desirability of Outcome Ranking Analysis of a Randomized Clinical Trial Comparing Seven Versus Fourteen Days of Antibiotics for Uncomplicated Gram-Negative Bloodstream Infection.
    (Open forum infectious diseases, 2022-06) Howard-Anderson, Jessica; Dai, Weixiao; Yahav, Dafna; Hamasaki, Toshimitsu; Turjeman, Adi; Koppel, Fidi; Franceschini, Erica; Hill, Carol; Sund, Zoë; Chambers, Henry F; Fowler, Vance G; Boucher, Helen W; Evans, Scott R; Paul, Mical; Holland, Thomas L; Doernberg, Sarah B

    Background

    Although a short course (7 days) of antibiotics has been demonstrated to be noninferior to a conventional course (14 days) in terms of mortality and infectious complications for patients with a Gram-negative bacterial bloodstream infection (GNB), it is unknown whether a shorter treatment duration can provide a better overall clinical outcome.

    Methods

    We applied a bloodstream infection-specific desirability of outcome ranking (DOOR) analysis to the results of a previously completed, randomized controlled trial comparing short versus conventional course antibiotic therapy for hospitalized patients with uncomplicated GNB. We determined the probability that a randomly selected participant in the short course group would have a more desirable overall outcome than a participant in the conventional duration group. We performed (1) partial credit analyses allowing for calculated and variable weighting of DOOR ranks and (2) subgroup analyses to elucidate which patients may benefit the most from short durations of therapy.

    Results

    For the 604 patients included in the original study (306 short course, 298 conventional course), the probability of having a more desirable outcome with a short course of antibiotics compared with a conventional course was 51.1% (95% confidence interval, 46.7% to 55.4%), indicating no significant difference. Partial credit analyses indicated that the DOOR results were similar across different patient preferences. Prespecified subgroup analyses using DOOR did not reveal significant differences between short and conventional courses of therapy.

    Conclusions

    Both short and conventional durations of antibiotic therapy provide comparable clinical outcomes when using DOOR to consider benefits and risks of treatment options for GNB.
  • Thumbnail Image
    ItemOpen Access
    Analytical Evaluation of the Abbott RealTime CT/NG Assay for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Rectal and Pharyngeal Swabs.
    (The Journal of molecular diagnostics : JMD, 2020-06) Adamson, Paul C; Pandori, Mark W; Doernberg, Sarah B; Komarow, Lauren; Sund, Zoe; Tran, Thuy Tien T; Jensen, David; Tsalik, Ephraim L; Deal, Carolyn D; Chambers, Henry F; Fowler, Vance G; Evans, Scott R; Patel, Robin; Klausner, Jeffrey D; Antibacterial Resistance Leadership Group
    Chlamydia trachomatis and Neisseria gonorrhoeae infections in the rectum and pharynx are important extragenital reservoirs of infection. Few assays approved by the US Food and Drug Administration are commercially available to diagnose pharyngeal or rectal infections. The current study reports on the analytical performance of the Abbott RealTime CT/NG assay, including the limit of detection, inclusivity, and analytical specificity for C. trachomatis and N. gonorrhoeae in rectal and pharyngeal specimens. The limit of detection was performed using known concentrations of organisms, elementary bodies per milliliter (EB/mL) for C. trachomatis and colony-forming units per milliliter (CFU/mL) for N. gonorrhoeae, in clinical rectal and pharyngeal swab matrices. Inclusivity was performed against 12 serovars of C. trachomatis and seven strains of N. gonorrhoeae. The analytical specificity was performed using 28 different bacteria and viruses. The limit of detection for C. trachomatis was 2.56 EB/mL in pharyngeal specimens and 12.8 EB/mL in rectal specimens. The limit of detection for N. gonorrhoeae was 0.0256 CFU/mL for both pharyngeal and rectal specimens. The inclusivity and analytical specificity were 100% for both rectal and pharyngeal specimens. These analytical performance data demonstrate that the Abbott CT/NG RealTime assay is an accurate, sensitive, and specific assay in rectal and pharyngeal specimens, supporting the potential of the assay for detection of rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections.
  • Thumbnail Image
    ItemOpen Access
    Antibacterial Resistance Leadership Group 2.0: Back to Business.
    (Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2021-08) Chambers, Henry F; Evans, Scott R; Patel, Robin; Cross, Heather R; Harris, Anthony D; Doi, Yohei; Boucher, Helen W; van Duin, David; Tsalik, Ephraim L; Holland, Thomas L; Pettigrew, Melinda M; Tamma, Pranita D; Hodges, Kathryn R; Souli, Maria; Fowler, Vance G
    In December 2019, the Antibacterial Resistance Leadership Group (ARLG) was awarded funding for another 7-year cycle to support a clinical research network on antibacterial resistance. ARLG 2.0 has 3 overarching research priorities: infections caused by antibiotic-resistant (AR) gram-negative bacteria, infections caused by AR gram-positive bacteria, and diagnostic tests to optimize use of antibiotics. To support the next generation of AR researchers, the ARLG offers 3 mentoring opportunities: the ARLG Fellowship, Early Stage Investigator seed grants, and the Trialists in Training Program. The purpose of this article is to update the scientific community on the progress made in the original funding period and to encourage submission of clinical research that addresses 1 or more of the research priority areas of ARLG 2.0.
  • Thumbnail Image
    ItemOpen Access
    Can ceftazidime/avibactam and aztreonam overcome β-lactam resistance conferred by metallo-β-lactamases in Enterobacteriaceae?
    (Antimicrob Agents Chemother, 2017-02-06) Marshall, Steven; Hujer, Andrea M; Rojas, Laura J; Papp-Wallace, Krisztina M; Humphries, Romney M; Spellberg, Brad; Hujer, Kristine M; Marshall, Emma K; Rudin, Susan D; Perez, Federico; Wilson, Brigid M; Wasserman, Ronald B; Chikowski, Linda; Paterson, David L; Vila, Alejandro J; van Duin, David; Kreiswirth, Barry N; Chambers, Henry F; Fowler, Vance G; Jacobs, Michael R; Pulse, Mark E; Weiss, William J; Bonomo, Robert A
    Based upon knowledge of the hydrolytic profile of major β-lactamases found in Gram negative bacteria, we tested the effectiveness of the combination of ceftazidime/avibactam (CAZ/AVI) with aztreonam (ATM) against carbapenem-resistant enteric bacteria possessing metallo-β-lactamases (MBLs). Disk-diffusion and agar based antimicrobial susceptibility testing were initially performed to determine the in vitro efficacy of a unique combination of CAZ/AVI and ATM against 21 representative Enterobacteriaceae isolates with a complex molecular background that included blaIMP, blaNDM, blaOXA-48, blaCTX-M, blaAmpC, and combinations thereof. Time-kill assays were conducted, and the in vivo efficacy of this combination was assessed in a murine neutropenic thigh infection model. By disk diffusion assay, all 21 isolates were resistant to CAZ/AVI alone, and 19/21 were resistant to ATM. The in vitro activity of CAZ/AVI in combination with ATM against diverse Enterobacteriaceae possessing MBLs was demonstrated in 17/21 isolates, where the zone of inhibition was ≥ 21 mm. All isolates demonstrated a reduction in CAZ/AVI agar dilution MICs with the addition of ATM. At 2 h, time-kill assays demonstrated a ≥ 4 log10 CFU decrease for all groups that had CAZ/AVI plus ATM (8 μg/ml) added, compared to the CAZ/AVI alone group. In the murine neutropenic thigh infection model, an almost 4 log10 reduction in CFUs was noted at 24 h for CAZ/AVI (32 mg/kg q8h) plus ATM (32 mg/kg q8h) vs. CAZ/AVI (32 mg/kg q8h) alone. The data presented herein, requires us to carefully consider this new therapeutic combination to treat infections caused by MBL-producing Enterobacteriaceae.
  • Thumbnail Image
    ItemOpen Access
    Clinical outcomes and bacterial characteristics of carbapenem-resistant Klebsiella pneumoniae complex among patients from different global regions (CRACKLE-2): a prospective, multicentre, cohort study.
    (The Lancet. Infectious diseases, 2021-11-09) Wang, Minggui; Earley, Michelle; Chen, Liang; Hanson, Blake M; Yu, Yunsong; Liu, Zhengyin; Salcedo, Soraya; Cober, Eric; Li, Lanjuan; Kanj, Souha S; Gao, Hainv; Munita, Jose M; Ordoñez, Karen; Weston, Greg; Satlin, Michael J; Valderrama-Beltrán, Sandra L; Marimuthu, Kalisvar; Stryjewski, Martin E; Komarow, Lauren; Luterbach, Courtney; Marshall, Steve H; Rudin, Susan D; Manca, Claudia; Paterson, David L; Reyes, Jinnethe; Villegas, Maria V; Evans, Scott; Hill, Carol; Arias, Rebekka; Baum, Keri; Fries, Bettina C; Doi, Yohei; Patel, Robin; Kreiswirth, Barry N; Bonomo, Robert A; Chambers, Henry F; Fowler, Vance G; Arias, Cesar A; van Duin, David; Multi-Drug Resistant Organism Network Investigators

    Background

    Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a global threat. We therefore analysed the bacterial characteristics of CRKP infections and the clinical outcomes of patients with CRKP infections across different countries.

    Methods

    In this prospective, multicentre, cohort study (CRACKLE-2), hospitalised patients with cultures positive for CRKP were recruited from 71 hospitals in Argentina, Australia, Chile, China, Colombia, Lebanon, Singapore, and the USA. The first culture positive for CRKP was included for each unique patient. Clinical data on post-hospitalisation death and readmission were collected from health records, and whole genome sequencing was done on all isolates. The primary outcome was a desirability of outcome ranking at 30 days after the index culture, and, along with bacterial characteristics and 30-day all-cause mortality (a key secondary outcome), was compared between patients from China, South America, and the USA. The desirability of outcome ranking was adjusted for location before admission, Charlson comorbidity index, age at culture, Pitt bacteremia score, and anatomical culture source through inverse probability weighting; mortality was adjusted for the same confounders, plus region where relevant, through multivariable logistic regression. This study is registered at ClinicalTrials.gov, NCT03646227, and is complete.

    Findings

    Between June 13, 2017, and Nov 30, 2018, 991 patients were enrolled, of whom 502 (51%) met the criteria for CRKP infection and 489 (49%) had positive cultures that were considered colonisation. We observed little intra-country genetic variation in CRKP. Infected patients from the USA were more acutely ill than were patients from China or South America (median Pitt bacteremia score 3 [IQR 2-6] vs 2 [0-4] vs 2 [0-4]) and had more comorbidities (median Charlson comorbidity index 3 [IQR 2-5] vs 1 [0-3] vs 1 [0-2]). Adjusted desirability of outcome ranking outcomes were similar in infected patients from China (n=246), South America (n=109), and the USA (n=130); the estimates were 53% (95% CI 42-65) for China versus South America, 50% (41-61) for the USA versus China, and 53% (41-66) for the USA versus South America. In patients with CRKP infections, unadjusted 30-day mortality was lower in China (12%, 95% CI 8-16; 29 of 246) than in the USA (23%, 16-30; 30 of 130) and South America (28%, 20-37; 31 of 109). Adjusted 30-day all-cause mortality was higher in South America than in China (adjusted odds ratio [aOR] 4·82, 95% CI 2·22-10·50) and the USA (aOR 3·34, 1·50-7·47), with the mortality difference between the USA and China no longer being significant (aOR 1·44, 0·70-2·96).

    Interpretation

    Global CRKP epidemics have important regional differences in patients' baseline characteristics and clinical outcomes, and in bacterial characteristics. Research findings from one region might not be generalisable to other regions.

    Funding

    The National Institutes of Health.
  • Thumbnail Image
    ItemOpen Access
    Improving Traditional Registrational Trial End Points: Development and Application of a Desirability of Outcome Ranking End Point for Complicated Urinary Tract Infection Clinical Trials.
    (Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2023-02) Howard-Anderson, Jessica; Hamasaki, Toshimitsu; Dai, Weixiao; Collyar, Deborah; Rubin, Daniel; Nambiar, Sumathi; Kinamon, Tori; Hill, Carol; Gelone, Steven P; Mariano, David; Baba, Takamichi; Holland, Thomas L; Doernberg, Sarah B; Chambers, Henry F; Fowler, Vance G; Evans, Scott R; Boucher, Helen W

    Background

    Traditional end points used in registrational randomized, controlled trials (RCTs) often do not allow for complete interpretation of the full range of potential clinical outcomes. Desirability of outcome ranking (DOOR) is an approach to the design and analysis of clinical trials that incorporates benefits and risks of novel treatment strategies and provides a global assessment of patient experience.

    Methods

    Through a multidisciplinary committee of experts in infectious diseases, clinical trial design, drug regulation, and patient experience, we developed a DOOR end point for infectious disease syndromes and demonstrated how this could be applied to 3 registrational drug trials (ZEUS, APEKS-cUTI, and DORI-05) for complicated urinary tract infections (cUTIs). ZEUS compared fosfomycin to piperacillin/tazobactam, APEKS-cUTI compared cefiderocol to imipenem, and DORI-05 compared doripenem to levofloxacin. Using DOOR, we estimated the probability of a more desirable outcome with each investigational antibacterial drug.

    Results

    In each RCT, the DOOR distribution was similar and the probability that a patient in the investigational arm would have a more desirable outcome than a patient in the control arm had a 95% confidence interval containing 50%, indicating no significant difference between treatment arms. DOOR facilitated improved understanding of potential trade-offs between clinical efficacy and safety. Partial credit and subgroup analyses also highlight unique attributes of DOOR.

    Conclusions

    DOOR can effectively be used in registrational cUTI trials. The DOOR end point presented here can be adapted for other infectious disease syndromes and prospectively incorporated into future clinical trials.
  • Thumbnail Image
    ItemOpen Access
    Short- vs Standard-Course Outpatient Antibiotic Therapy for Community-Acquired Pneumonia in Children: The SCOUT-CAP Randomized Clinical Trial.
    (JAMA pediatrics, 2022-01-18) Williams, Derek J; Creech, C Buddy; Walter, Emmanuel B; Martin, Judith M; Gerber, Jeffrey S; Newland, Jason G; Howard, Lee; Hofto, Meghan E; Staat, Mary A; Oler, Randolph E; Tuyishimire, Bonifride; Conrad, Thomas M; Lee, Marina S; Ghazaryan, Varduhi; Pettigrew, Melinda M; Fowler, Vance G; Chambers, Henry F; Zaoutis, Theoklis E; Evans, Scott; Huskins, W Charles; The DMID 14-0079 Study Team

    Importance

    Childhood community-acquired pneumonia (CAP) is usually treated with 10 days of antibiotics. Shorter courses may be effective with fewer adverse effects and decreased potential for antibiotic resistance.

    Objective

    To compare a short (5-day) vs standard (10-day) antibiotic treatment strategy for CAP in young children.

    Design, setting, and participants

    Randomized double-blind placebo-controlled clinical trial in outpatient clinic, urgent care, or emergency settings in 8 US cities. A total of 380 healthy children aged 6 to 71 months with nonsevere CAP demonstrating early clinical improvement were enrolled from December 2, 2016, to December 16, 2019. Data were analyzed from January to September 2020.

    Intervention

    On day 6 of their originally prescribed therapy, participants were randomized 1:1 to receive 5 days of matching placebo or 5 additional days of the same antibiotic.

    Main outcomes and measures

    The primary end point was the end-of-treatment response adjusted for duration of antibiotic risk (RADAR), a composite end point that ranks each child's clinical response, resolution of symptoms, and antibiotic-associated adverse effects in an ordinal desirability of outcome ranking (DOOR). Within each DOOR rank, participants were further ranked by the number of antibiotic days, assuming that shorter antibiotic durations were more desirable. Using RADAR, the probability of a more desirable outcome was estimated for the short- vs standard-course strategy. In a subset of children, throat swabs were collected between study days 19 and 25 to quantify antibiotic resistance genes in oropharyngeal flora.

    Results

    A total of 380 children (189 randomized to short course and 191 randomized to standard course) made up the study population. The mean (SD) age was 35.7 (17.2) months, and 194 participants (51%) were male. Of the included children, 8 were Asian, 99 were Black or African American, 234 were White, 32 were multiracial, and 7 were of unknown or unreported race; 33 were Hispanic or Latino, 344 were not Hispanic or Latino, and 3 were of unknown or unreported ethnicity. There were no differences between strategies in the DOOR or its individual components. Fewer than 10% of children in either strategy had an inadequate clinical response. The short-course strategy had a 69% (95% CI, 63-75) probability of a more desirable RADAR outcome compared with the standard-course strategy. A total of 171 children were included in the resistome analysis. The median (range) number of antibiotic resistance genes per prokaryotic cell (RGPC) was significantly lower in the short-course strategy compared with the standard-course strategy for total RGPC (1.17 [0.35-2.43] vs 1.33 [0.46-11.08]; P = .01) and β-lactamase RGPC (0.55 [0.18-1.24] vs 0.60 [0.21-2.45]; P = .03).

    Conclusions and relevance

    In this study, among children responding to initial treatment for outpatient CAP, a 5-day antibiotic strategy was superior to a 10-day strategy. The shortened approach resulted in similar clinical response and antibiotic-associated adverse effects, while reducing antibiotic exposure and resistance.

    Trial registration

    ClinicalTrials.gov Identifier: NCT02891915.
  • Thumbnail Image
    ItemOpen Access
    Simultaneous Evaluation of Diagnostic Assays for Pharyngeal and Rectal Neisseria gonorrhoeae and Chlamydia trachomatis Using a Master Protocol.
    (Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2020-12) Doernberg, Sarah B; Komarow, Lauren; Tran, Thuy Tien T; Sund, Zoe; Pandori, Mark W; Jensen, David; Tsalik, Ephraim L; Deal, Carolyn D; Chambers, Henry F; Fowler, Vance G; Evans, Scott R; Patel, Robin; Klausner, Jeffrey D

    Background

    Pharyngeal and rectal Neisseria gonorrhoeae and Chlamydia trachomatis play important roles in infection and antibacterial resistance transmission, but no US Food and Drug Administration (FDA)-cleared assays for detection at these sites existed prior to this study. The objective was to estimate performance of assays to detect those infections in pharyngeal and rectal specimens to support regulatory submission.

    Methods

    We performed a cross-sectional, single-visit study of adults seeking sexually transmitted infection testing at 9 clinics in 7 states. We collected pharyngeal and rectal swabs from participants. The primary outcome was positive and negative percent agreement for detection of N. gonorrhoeae and C. trachomatis for 3 investigational assays compared to a composite reference. Secondary outcomes included positivity as well as positive and negative predictive values and likelihood ratios. Subgroup analyses included outcomes by symptom status and sex.

    Results

    A total of 2598 participants (79% male) underwent testing. We observed N. gonorrhoeae positivity of 8.1% in the pharynx and 7.9% in the rectum and C. trachomatis positivity of 2.0% in the pharynx and 8.7% in the rectum. Positive percent agreement ranged from 84.8% to 96.5% for different anatomic site infection combinations, whereas negative percent agreement was 98.8% to 99.6%.

    Conclusions

    This study utilized a Master Protocol to generate diagnostic performance data for multiple assays from different manufacturers in a single study population, which ultimately supported first-in-class FDA clearance for extragenital assays. We observed very good positive percent agreement when compared to a composite reference method for the detection of both pharyngeal and rectal N. gonorrhoeae and C. trachomatis.

    Clinical trials registration

    NCT02870101.