Publications by authors named "Robert C Kalayjian"

Article Synopsis
  • Ferroptosis, a type of cell death linked to iron levels, may play a role in HIV-related brain issues and neurocognitive impairment, showing potential variation by sex.
  • Researchers studied ferritin levels (specifically FTH1 and FTL) and lipid peroxidation markers in 324 people with HIV, discovering that higher ferritin levels were linked to better cognitive function, particularly in women.
  • The positive effects of ferritins on cognitive performance were noted to last for up to five years, indicating that they may protect against brain damage caused by ferroptosis, but larger studies are needed to validate these findings and understand the mechanisms involved.
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Background: Carbapenem-resistant Klebsiella pneumoniae (CRKp) is the most prevalent carbapenem-resistant Enterobacterales in the United States. We evaluated CRKp clustering in patients in US hospitals.

Methods: From April 2016 to August 2017, 350 patients with clonal group 258 CRKp were enrolled in the Consortium on Resistance Against Carbapenems in Klebsiella and other Enterobacteriaceae, a prospective, multicenter, cohort study.

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Antimicrobial resistance is a global threat. As "proof-of-concept," we employed a system-based approach to identify patient, bacterial, and drug variables contributing to mortality in patients with carbapenem-resistant Klebsiella pneumoniae (CR) bloodstream infections exposed to colistin (COL) and ceftazidime-avibactam (CAZ/AVI) as mono- or combination therapies. Patients ( = 49) and CR isolates ( = 22) were part of the Consortium on Resistance Against Carbapenems in Klebsiella and other Enterobacteriaceae (CRACKLE-1), a multicenter, observational, prospective study of patients with carbapenem-resistant Enterobacterales (CRE) conducted between 2011 and 2016.

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Background: The mechanisms underlying naïve CD4+ lymphopenia during chronic Hepatitis C Virus (HCV) infection are unclear. Whether direct-acting antiviral (DAA) therapy restores peripheral naïve CD4+ T cell numbers and function is unknown.

Methods: We enumerated frequencies and counts of peripheral naïve CD4+, CD4+CD31+ and CD4+CD31- T cells by flow cytometry in a cross sectional analysis comparing chronic HCV infected (n=34), DAA-treated(n=29), and age-range matched controls (n=25), as well as in a longitudinal cohort of HCV DAA treated persons (n=16).

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Background: Neurocognitive impairment (NCI) is associated with monocyte activation in people with HIV (PWH). Activated monocytes increase glycolysis, reduce oxidative phosphorylation, and accumulate citrate and succinate, tricarboxylic acid (TCA) cycle metabolites that promote inflammation-this metabolic shift may contribute to NCI and slowed gait speed in PWH.

Methods: Plasma citrate and succinate were assayed by liquid chromatography-mass spectrometry from 957 participants upon entry to a multicenter, prospective cohort of older PWH.

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Background: Predicting mortality risk in patients is important in research settings. The Pitt bacteremia score (PBS) is commonly used as a predictor of early mortality risk in patients with bloodstream infections (BSIs). We determined whether the PBS predicts 14-day inpatient mortality in nonbacteremia carbapenem-resistant Enterobacteriaceae (CRE) infections.

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Objective: To examine associations between plasma cystatin C and neurocognitive impairment (NCI) and its performance as a diagnostic marker before and during initial antiretroviral therapy (ART).

Methods: Multivariable logistic regression and generalized estimating equations examined associations with NCI, determined by neuropsychological measurements, in participants of a 48-week randomized clinical trial of initial ART. Receiver operator characteristic curves examined diagnostic models of NCI.

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In the Consortium on Resistance Against Carbapenems in and other (CRACKLE), trimethoprim-sulfamethoxazole (TMP-SMX) had a limited role in the treatment of less severe carbapenem-resistant (CRE) infections, especially urinary tract infections. Of tested CRE, only 29% were susceptible to TMP-SMX. Development of resistance further limits the use of TMP-SMX in CRE infections.

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Objective: We compared bone mineral density (BMD) changes and their correlates, between men and women participating in two randomized trials of initial [antiretroviral therapy (ART)] regimens, with or without tenofovir disoproxil fumarate (TDF).

Methods: Covariates in linear regression models of 48-week hip and spine %BMD changes, by dual energy X-ray absorptiometry, included baseline and 48-week changes in plasma viral load, CD4 cells, plasma C-terminal telopeptide, procollagen 1 N-terminal propeptide and glomerular filtration rates, and the 48-week area under the curve of fractional excretion of phosphate.

Results: Despite overall hip and spine BMD declines of 2.

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Background: Chronic hepatitis C virus (HCV) and HIV infections are associated with impaired responses to neo-antigens contained in hepatitis A virus (HAV)/hepatitis B virus (HBV) vaccines, yet responsible mechanisms are unclear.

Methods: ACTG 5232 and CFAR0910 were clinical trials where pre-vaccine levels of plasma IP10, IL-6, sCD163 and sCD14 were measured in viremic HCV- (n = 15) or HIV-infected participants (n = 24) and uninfected controls (n = 10). Accelerated dosing HAV/HBV vaccine and tetanus booster were administered and antibody response was measured at 0, 1, 3, 8, and 24 weeks.

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Background: Patients on chronic intermittent renal replacement therapy (RRT) are at risk for infection with carbapenem-resistant Enterobacteriaceae (CRE). However, the impact of RRT on outcomes after CRE infections remains to be defined. Here we perform a comparison of outcomes for CRE-infected patients with preserved renal function compared with CRE-infected patients on RRT.

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Background: This study was performed to characterize the epidemiology, management, and outcomes of skin and soft tissue infection (SSTI) and colonization due to carbapenem-resistant (CRE).

Methods: Patients from the Consortium on Resistance Against Carbapenem in and Other (CRACKLE-1) from December 24, 2011 to October 1, 2014 with wound cultures positive for CRE were included in the study. Predictors of surgical intervention were analyzed.

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Background: The efficacy of ceftazidime-avibactam-a cephalosporin-β-lactamase inhibitor combination with in vitro activity against Klebsiella pneumoniae carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CRE)-compared with colistin remains unknown.

Methods: Patients initially treated with either ceftazidime-avibactam or colistin for CRE infections were selected from the Consortium on Resistance Against Carbapenems in Klebsiella and other Enterobacteriaceae (CRACKLE), a prospective, multicenter, observational study. Efficacy, safety, and benefit-risk analyses were performed using intent-to-treat analyses with partial credit and the desirability of outcome ranking approaches.

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Background: Although statins, angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) are generally well tolerated, the impact of these therapies individually or in combination on the change in neurocognitive function in persons with human immunodeficiency virus infection is unknown.

Methods: The study included participants in the AIDS Clinical Trials Group Longitudinal Linked Randomized Trials cohort participants not receiving a statin or ACEI/ARB within 30 days of first neurologic assessment (baseline), with assessments by NPZ-3 (z score of averaged Trailmaking A and B tests and digit symbol test [DST]) from ≥2 measurements. Marginal structural models estimated the causal effect of statin or ACEI/ARB initiation on neurocognitive function; initial constant slope was assumed during the first year of treatment and a second constant slope thereafter.

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Persons living with HIV (PLWH) have accentuated risks for age-associated comorbidities. Compared to the general population, PLWH have a 2-fold higher risk of cardiovascular disease, a 3-fold increased risk of fracture, and a risk of kidney disease that is comparable to that in diabetes. Some comorbidities may present at younger ages than among the general population, suggesting the possibility of accelerated aging with HIV infection.

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The impact of antiretroviral therapy (ART) on frailty among human immunodeficiency virus (HIV)-infected adults has not been well described. HIV-infected participants aged ≥40 years with initial ART receipt through a randomized, controlled AIDS Clinical Trials Group trial completed a frailty assessment. Ordinal logistic regression models examined factors associated with frailty.

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Background: Older human immunodeficiency virus (HIV)-infected adults may experience higher rates of frailty and disability than the general population. Improved understanding of the prevalence, risk factors, and types of impairment can better inform providers and the healthcare system.

Methods: HIV-infected participants within the AIDS Clinical Trials Group A5322 HAILO study self-reported disability by the Lawton-Brody Instrumental Activities of Daily Living (IADL) Questionnaire.

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Background: Polymyxins including colistin are an important "last-line" treatment for infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKp). Increasing use of colistin has led to resistance to this cationic antimicrobial peptide.

Methods: A cohort nested within the Consortium on Resistance against Carbapenems in Klebsiella pneumoniae (CRACKLE) was constructed of patients with infection, or colonization with CRKp isolates tested for colistin susceptibility during the study period of December, 2011 to October, 2014.

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Background: Various transmission routes contribute to spread of carbapenem-resistant Klebsiella pneumoniae (CRKP) in hospitalized patients. Patients with readmissions during which CRKP is again isolated ("CRKP readmission") potentially contribute to transmission of CRKP.

Objective: To evaluate CRKP readmissions in the Consortium on Resistance against Carbapenems in K.

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Carbapenem-resistant Enterobacteriaceae (CRE) usually infect patients with significant comorbidities and health care exposures. We present a case of a pregnant woman who developed community-acquired pyelonephritis caused by KPC-producing Klebsiella pneumoniae. Despite antibiotic treatment, she experienced spontaneous prolonged rupture of membranes, with eventual delivery of a healthy infant.

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Objective: To determine the rates of and risk factors for tigecycline nonsusceptibility among carbapenem-resistant Klebsiella pneumoniae (CRKPs) isolated from hospitalized patients.

Design: Multicenter prospective observational study.

Setting: Acute care hospitals participating in the Consortium on Resistance against Carbapenems in Klebsiella pneumoniae (CRaCKle).

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Article Synopsis
  • Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a significant pathogen linked to healthcare-associated infections, particularly urinary tract infections (UTIs).
  • A study evaluated the effects of CRKP strain types and treatment methods on the outcomes of 157 patients with CRKP bacteriuria, finding that treatment with aminoglycosides led to better results compared to tigecycline.
  • The predominant strain types were ST258A and ST258B, with ST258A associated with a higher likelihood of clinical failure, indicating that both strain type and treatment choices are crucial for patient outcomes.
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It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

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Older HIV infected subjects were previously found to have significant B cell expansion during initial antiretroviral therapy in a prospective age-differentiated cohort of older and younger (≥45 vs. ≤30 years) HIV-infected subjects initiating antiretroviral therapy (ART) through the AIDS Clinical Trials Group. Here to further describe this expansion, using a subset of subjects from the same cohort, we characterized B cell phenotypes at baseline and after 192 weeks of ART in both older and younger HIV-infected groups and compared them to uninfected age-matched controls.

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